AETHER SYSTEMS LLC
S-1, 2000-02-22
COMPUTER INTEGRATED SYSTEMS DESIGN
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<PAGE>   1

   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON FEBRUARY 22, 2000.
                                                      REGISTRATION NO. 333-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549
                             ----------------------

                                    FORM S-1
                        REGISTRATION STATEMENT UNDER THE
                             SECURITIES ACT OF 1933
                             ----------------------

                              AETHER SYSTEMS, INC.
             (Exact Name of Registrant as Specified in Its Charter)

<TABLE>
<S>                                <C>                                <C>
             DELAWARE                             7373                            52-2186634
   (State or Other Jurisdiction       (Primary Standard Industrial             (I.R.S. Employer
of Incorporation or Organization)     Classification Code Number)            Identification No.)
</TABLE>

                             ----------------------

                             11460 CRONRIDGE DRIVE
                          OWINGS MILLS, MARYLAND 21117
                                 (410) 654-6400
  (Address, Including Zip Code, and Telephone Number, Including Area Code, of
                   Registrant's Principal Executive Offices)
                             ----------------------

                                 DAVID S. OROS
                CHAIRMAN, CHIEF EXECUTIVE OFFICER AND PRESIDENT
                             11460 CRONRIDGE DRIVE
                          OWINGS MILLS, MARYLAND 21117
                                 (410) 654-6400
 (Name, Address, Including Zip Code, and Telephone Number, Including Area Code,
                             of Agent for Service)
                             ----------------------

                                with copies to:

<TABLE>
<S>                                                      <C>
                  MARK A. DEWIRE, ESQ.                                     EVE N. HOWARD, ESQ.
                ROGER J. PATTERSON, ESQ.                                  HOGAN & HARTSON L.L.P.
               WILMER, CUTLER & PICKERING                                 555 13TH STREET, N.W.
                  2445 M STREET, N.W.                                     WASHINGTON, D.C. 20004
                 WASHINGTON, D.C. 20037                                       (202) 637-5600
                     (202) 663-6000
</TABLE>

                             ----------------------

    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the effective date of this Registration Statement.
    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, check the following box.  [ ]
    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  [ ]
    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  [ ]
    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [ ]
                             ----------------------

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------
                                                         PROPOSED MAXIMUM    PROPOSED MAXIMUM
         TITLE OF EACH CLASS OF           AMOUNT TO BE    OFFERING PRICE    AGGREGATE OFFERING       AMOUNT OF
      SECURITIES TO BE REGISTERED          REGISTERED      PER UNIT(1)            PRICE           REGISTRATION FEE
- ------------------------------------------------------------------------------------------------------------------
<S>                                       <C>            <C>                <C>                   <C>
Common Stock, par value $.01 per
  share.................................     3,450,000       $202.00           $696,900,000           $183,982
- ------------------------------------------------------------------------------------------------------------------
Convertible Subordinated Notes due
  2005..................................  $230,000,000       N/A               $230,000,000(2)        $ 60,720
- ------------------------------------------------------------------------------------------------------------------
Common Stock, par value $.01 per share,
  issuable upon conversion of
  Convertible Subordinated Notes due
  2005(3)...............................       --            --                   --                   --
- ------------------------------------------------------------------------------------------------------------------
  Total.................................       --            --                $926,900,000           $244,702
- ------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------
</TABLE>

(1) Estimated solely for the purpose of calculating the registration fee
    pursuant to Rule 457(c) under the Securities Act of 1933.
(2) Exclusive of accrued interest, if any. Estimated solely for the purpose of
    computing the amount of the registration fee.
(3) No additional consideration will be received for any shares of common stock
    issued upon conversion of the Convertible Subordinated Notes. Pursuant to
    Rule 416 under the Securities Act of 1933, this registration statement also
    includes an indeterminate number of shares that may be issued upon
    conversion of the convertible subordinated notes as a result of
    anti-dilution and other provisions of the notes.

    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THIS REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   2

                                EXPLANATORY NOTE

     This registration statement contains three separate prospectuses. Two
prospectuses relate to a public offering of our common stock, par value $.01 per
share. One of the common stock prospectuses will be used in connection with a
United States and Canadian offering and the other will be used in a concurrent
international offering. The two common stock prospectuses will be identical
except for the front and back cover pages and underwriting section. The form of
prospectus for the United States and Canadian common stock offering is included
in this registration statement and the form of the front and back cover pages
and underwriting section for the international common stock prospectus follows
the United States common stock prospectus. The third prospectus relates to a
concurrent United States and Canadian offering of our convertible subordinated
notes due 2005 and this prospectus follows the pages for the international
common stock prospectus.
<PAGE>   3

       THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE
       MAY NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH
       THE SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS
       NOT AN OFFER TO SELL THESE SECURITIES AND IT IS NOT SOLICITING AN OFFER
       TO BUY THESE SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT
       PERMITTED.

                             SUBJECT TO COMPLETION
                 PRELIMINARY PROSPECTUS DATED FEBRUARY 22, 2000
PROSPECTUS
- ----------

                                3,000,000 SHARES

                                 [AETHER LOGO]

                                  COMMON STOCK
                            ------------------------

        Aether Systems, Inc. is selling 2,346,219 shares and Aether stockholders
are selling 653,781 shares. The U.S. underwriters are offering 2,550,000 shares
in the U.S. and Canada and the international managers are offering 450,000
shares outside the U.S. and Canada.

        The shares are quoted on the Nasdaq National Market under the symbol
"AETH." On February 18, 2000, the last sale price of the shares as reported on
the Nasdaq National Market was $203 per share.

        Concurrent with this offering, we are offering $200,000,000 aggregate
principal amount of our   % convertible subordinated notes due 2005. The notes
will be convertible into shares of our common stock at the option of the holder.
We are offering the convertible notes through a separate prospectus. Completion
of the convertible notes offering is not a condition to the completion of this
offering.

        INVESTING IN THE COMMON STOCK INVOLVES RISKS THAT ARE DESCRIBED IN THE
"RISK FACTORS" SECTION BEGINNING ON PAGE 9 OF THIS PROSPECTUS.
                            ------------------------

<TABLE>
<CAPTION>
                                   PER SHARE    TOTAL
                                   ---------    -----
<S>                                <C>          <C>
Public offering price...........        $         $
Underwriting discount...........        $         $
Proceeds, before expenses,
  to Aether.....................        $         $
Proceeds, before expenses,
  to the selling stockholders...        $         $
</TABLE>

        The U.S. underwriters may also purchase up to an additional 135,327
shares from Aether, and up to an additional 247,173 shares from the selling
stockholders, at the public offering price, less the underwriting discount,
within 30 days from the date of this prospectus to cover over-allotments. The
international managers may similarly purchase up to an additional 23,881 shares
from Aether and up to an additional 43,619 shares from the selling stockholders.

        Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

        The shares will be ready for delivery on or about           , 2000.

                            ------------------------

MERRILL LYNCH & CO.
         ROBERTSON STEPHENS
                  DONALDSON, LUFKIN & JENRETTE
                            U.S. BANCORP PIPER JAFFRAY
                                     BEAR, STEARNS & CO. INC.
                                            FRIEDMAN BILLINGS RAMSEY
                            ------------------------

             The date of this prospectus is                , 2000.
<PAGE>   4

     DESCRIPTION OF INSIDE FRONT COVER: The inside front cover contains the
Aether Systems logo and the slogan: "Wireless solutions for a portable planet."
Above the logo and slogan is a photograph depicting a finger pointing to a
globe.
<PAGE>   5

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                PAGE
                                                                ----
<S>                                                           <C>
Prospectus Summary..........................................      4
Risk Factors................................................      9
Forward-Looking Statements..................................     19
Use of Proceeds.............................................     20
Price Range of Common Stock.................................     20
Dividend Policy.............................................     20
Concurrent Offering.........................................     21
Capitalization..............................................     22
Dilution....................................................     24
Selected Consolidated Financial Data........................     25
Management's Discussion and Analysis of Financial Condition
  and Results of Operations.................................     27
Business....................................................     37
Management..................................................     57
Transactions Between Aether and its Officers, Directors or
  Significant Stockholders..................................     68
Principal and Selling Stockholders..........................     72
Description of Capital Stock................................     76
United States Federal Tax Consequences to Non-U.S. Holders
  of Common Stock...........................................     79
Shares Eligible for Future Sale.............................     82
Underwriting................................................     84
Legal Matters...............................................     87
Experts.....................................................     87
Where You Can Find More Information.........................     87
Index to Financial Statements...............................    F-1
</TABLE>

                         ------------------------------

     You should rely only on the information contained in this prospectus. We
have not, and the underwriters have not, authorized any other person to provide
you with different information. If anyone provides you with different or
inconsistent information, you should not rely on it. We are not, and the
underwriters are not, making an offer to sell these securities in any
jurisdiction where the offer or sale is not permitted. You should assume that
the information appearing in this prospectus is accurate only as of the date on
the front cover of this prospectus. Our business, financial condition, results
of operations and prospects may have changed since that date.

                                        3
<PAGE>   6

                               PROSPECTUS SUMMARY

     This summary does not contain all the information that may be important to
you. You should read the entire prospectus carefully, including the financial
data and related notes beginning on page F-1, before making an investment
decision.

OUR COMPANY

     We provide wireless data services, systems and software enabling people to
use handheld devices for mobile data communications and real-time transactions.
We design, develop, sell and support complete wireless systems for corporations
seeking to make data available to mobile workers or consumers. Our capabilities
include our wireless data engineering and development expertise, our wireless
integration software, our customer service and network operations center and,
following our acquisition of Riverbed Technologies, Inc., our mobile data
management software.

     We seek to develop and deliver wireless data services across a variety of
industries and market segments in the United States and internationally. Our
strategy initially focused on developing services for the financial services
sector, whose participants we believe are among the earliest adopters of
wireless data services. In the financial services industry, our current services
include TradeRunner, a real-time wireless trading and financial information
service offered to the online customers of Morgan Stanley Dean Witter Online,
the Reuters MarketClip service for financial market price quotes, alerts and
information and several services that deliver financial market information using
one- and two-way pagers. We currently are developing wireless trading and
financial services for other major financial institutions, including Charles
Schwab & Co., Inc.

     While seeking to extend our service offerings in the financial services
sector, we also seek to move into other industries and market segments. Since
January 2000, we have entered into the following acquisitions, investments,
agreements and letters of intent in pursuit of this strategy:

     - We agreed to acquire Riverbed, a company that develops and licenses
       mobile data management software. This pending acquisition gives us access
       to the industries Riverbed currently serves, including healthcare,
       transportation logistics and sales force automation.

     - We acquired LocusOne Communications, Inc., which develops wireless data
       systems for companies that distribute goods and services using their own
       delivery fleets. This acquisition extends our business to the
       transportation logistics and delivery industry.

     - We entered into a non-binding letter of intent with Reuters PLC to form a
       new company to develop wireless data systems in Europe, initially
       focusing on the financial services industry.

     - We agreed to form a new company, Inciscent, Inc., to develop wireless
       e-mail, two-way wireless data and Internet access and other applications
       for the small business and home office market segments. We agreed to form
       Inciscent with paging company Metrocall, Inc., Internet service provider
       PSINet Inc., investment firm Hicks, Muse, Tate & Furst Incorporated and
       other investors. As part of the investment, we also agreed to acquire
       approximately 9.9% of the outstanding capital stock of Metrocall for
       approximately $17 million.

     - We increased our investment in OmniSky Corporation (formerly doing
       business as OpenSky), a company we formed with 3Com Corporation. With our
       engineering assistance, OmniSky is developing wireless e-mail, Internet
       access and other electronic transactions primarily for the consumer
       market, and we have the right to offer these capabilities to our business
       customers.

     We have all the resources necessary to provide our customers with complete
wireless data systems. We have a large, experienced development team with 50
engineers, and with the acquisition of Riverbed we will add 34 engineers. We
have developed our package of wireless messaging software and software
development tools known as Aether Intelligent Messaging, or AIM, which serves as
a bridge to integrate

                                        4
<PAGE>   7

diverse corporate in-house data systems with a wide variety of wireless carrier
networks and end-user devices. Through our pending acquisition of Riverbed, we
will also provide a suite of software products that extend corporate data to
mobile handheld devices. We operate our own high-security network operations
center, which connects customer and other data to wireless networks, and we
maintain our own customer service center. We established the WAP Enterprise
Center, which is comprised of engineers who develop applications for wireless
phones that use the Wireless Application Protocol (so called WAP smartphones)
and the systems to support data communication to these devices. We have also
cultivated close relationships with major wireless network carriers, including
AT&T Wireless Services, Bell Atlantic Mobile and BellSouth Wireless Data and
mobile equipment and software vendors such as 3Com, Ericsson LM, Novatel
Wireless, Inc. and Phone.com, Inc.

     We believe we can provide our corporate customers with more attractive
service offerings by coupling general wireless applications like e-mail and
Internet access with custom corporate applications. We believe our involvement
with OmniSky and Inciscent will allow us to achieve this.

     Our Strategy.  Our strategy is to be the dominant provider of wireless data
services and systems to corporations by using our engineering expertise, our
software platforms, our customer service and network operations center and our
other resources. We seek to maximize recurring revenue by developing wireless
data services for a variety of industries and market segments in the United
States and internationally. We believe our capabilities and experience have
established us as an early market leader in wireless data services, and a key
element of our strategy is to move quickly into new opportunities to extend our
leadership position. Our strategy includes the following key elements:

     - Target a variety of industries and market segments for development of
       wireless data communications and services in the United States and
       internationally.

     - Continue to develop the market for existing and new services in the
       financial services sector.

     - Offer the widest range of software products to address every aspect of
       wireless integration and mobile data management for mobile workers and
       consumers.

     - Continue to develop mass-market wireless applications like e-mail and
       Internet access and bundle them with custom corporate applications.

     - Expand our customer base and strengthen the Aether brand through enhanced
       sales and marketing efforts.

     - Maintain and strengthen our strategic relationships with suppliers and
       customers.

     - Apply the expertise we gain through engineering services and research and
       development activities to emerging business opportunities.

     Operating results.  We had revenue of $1.8 million in 1997, $1.5 million in
1998 and $6.3 million in 1999. We had net losses of $2.7 million in 1997, $4.7
million in 1998 and $30.7 million in 1999. As of December 31, 1999, we had
cumulative losses of $38.5 million. On a pro forma basis, giving effect to the
acquisition of Mobeo, Inc. in September 1999 and LocusOne in February 2000, and
our pending acquisition of Riverbed, we had revenue of $16.1 million and net
losses of $435.0 million in 1999.

     Other information.  We are a Delaware corporation. In October 1999, we
completed our initial public offering of 6,900,000 shares of our common stock at
an initial offering price of $16.00 per share, which resulted in net proceeds of
approximately $101.1 million. All references to "we," "us," "our" or "Aether" in
this prospectus mean Aether Systems, Inc. and its subsidiaries or predecessors.

     Our principal executive offices are located at 11460 Cronridge Drive,
Owings Mills, Maryland 21117, and our telephone number is (410) 654-6400. We
maintain a Web site at www.aethersystems.com. Information contained in our Web
site does not constitute a part of this prospectus.

                                        5
<PAGE>   8

                                  THE OFFERING

<TABLE>
<S>                                            <C>
Common stock offered by us...................  2,346,219 shares
Common stock offered by the selling
  stockholders...............................  653,781 shares
Total common stock to be outstanding after
  the offering...............................  34,509,687 shares. This includes 4,537,286
                                               shares to be issued in connection with our
                                               acquisition of Riverbed and excludes:
                                               - shares of common stock issuable upon
                                                 conversion of the convertible notes
                                                 being offered concurrently;
                                               - 3,620,838 shares of common stock issuable
                                                 upon exercise of options outstanding at
                                                 December 31, 1999 or to be issued in
                                                 connection with our acquisition of
                                                 Riverbed, with a weighted average exercise
                                                 price of $6.76 per share;
                                               - 2,672,522 additional shares of common stock
                                                 reserved as of December 31, 1999 for future
                                                 issuance under our 1999 equity incentive
                                                 plan;
                                               - 1,175,000 shares of common stock issuable
                                                 upon exercise of warrants with a weighted
                                                 average exercise price of $1.96 per share;
                                               - 159,208 shares of common stock issuable
                                                 upon exercise of the underwriters'
                                                 over-allotment option; and
                                               - 893,665 shares of common stock contingently
                                                 issuable upon exercise of warrants with an
                                                 exercise price of $.01 per share, which may
                                                 be exercised if conditions are met.
Use of proceeds..............................  We currently intend to use the net proceeds
                                               from this offering and the concurrent notes
                                               offering for the following:
                                               - $100 million to acquire a 60% interest in
                                                 the company that is the subject of our letter
                                                 of intent with Reuters;
                                               - $19 million to repay indebtedness incurred
                                                 in connection with the LocusOne acquisition;
                                               - $17 million to make our investment in
                                                 Metrocall;
                                               - $10 million to make our investment in
                                                 Inciscent;
                                               - an estimated $25 million to enhance our
                                                 sales and marketing activities;
                                               - fund potential future acquisitions and
                                                 strategic investments; and
                                               - general corporate purposes.
Risk factors.................................  See "Risk Factors" beginning at page 9 for a
                                               discussion of factors you should consider
                                               carefully before deciding to invest in shares
                                               of our common stock.
Nasdaq National Market symbol................  AETH
</TABLE>

                                        6
<PAGE>   9

                              CONCURRENT OFFERING

     Concurrently with our offering of common stock, we are offering by means of
a separate prospectus $200,000,000 aggregate principal amount of   % convertible
subordinated notes due 2005. The convertible notes will be convertible at the
option of the holder into shares of our common stock. The completion of the
convertible notes offering is not a condition to the completion of this
offering. The sale of our convertible notes is described in greater detail on
page 21 under the heading "Concurrent Offering."

                                        7
<PAGE>   10

                      SUMMARY CONSOLIDATED FINANCIAL DATA
                (in thousands, except share and per share data)

     The following table summarizes our consolidated statements of operations
for each of the years ended December 31, 1996, 1997, 1998 and 1999 and our
consolidated balance sheet as of December 31, 1999. The pro forma consolidated
financial information gives effect to (i) the Mobeo and LocusOne acquisitions
and the pending acquisition of Riverbed, (ii) this offering of common stock and
the application of the net proceeds as described in "Use of Proceeds" on page 20
and (iii) the sale of $200 million of our convertible notes in a concurrent
public offering and the application of the net proceeds as described in "Use of
Proceeds" on page 20. The pro forma net loss per share information gives effect
to our conversion from a limited liability company to a corporation immediately
prior to our initial public offering.

     We have provided the pro forma consolidated financial information for
informational purposes only and you should not assume that our results would
actually have been as shown if we had acquired Mobeo, LocusOne and Riverbed or
had completed the offerings on the assumed dates, or that the information
projects what our results will be as a result of the acquisitions or offerings.
The pro forma consolidated statement of operations information assumes that the
transactions occurred on January 1, 1999, and the pro forma consolidated balance
sheet information assumes that the transactions occurred on December 31, 1999.
See our, Mobeo's and Riverbed's financial statements and notes to those
statements included in this prospectus beginning on page F-1.

<TABLE>
<CAPTION>
                                                                   YEAR ENDED DECEMBER 31,
                            -----------------------------------------------------------------------------------------------------
                                                                                                 1999 PRO FORMA
                                                                                -------------------------------------------------
                                                                                                                   ACQUISITIONS,
                                               HISTORICAL                                      ACQUISITIONS AND    COMMON STOCK
                            -------------------------------------------------                    COMMON STOCK     AND CONVERTIBLE
                               1996         1997         1998         1999      ACQUISITIONS       OFFERING       NOTES OFFERINGS
                            ----------   ----------   ----------   ----------   ------------   ----------------   ---------------
<S>                         <C>          <C>          <C>          <C>          <C>            <C>                <C>
CONSOLIDATED STATEMENT OF
OPERATIONS DATA:
Revenue:
  Subscriber revenue......  $       --   $      161   $      549   $    3,732    $   11,200       $   11,200         $   11,200
  Engineering services
    revenue...............       1,355        1,625          963        2,594         2,594            2,594              2,594
  Software and related
    services revenue......          --           --           --           --         2,317            2,317              2,317
                            ----------   ----------   ----------   ----------    ----------       ----------         ----------
  Total revenue...........       1,355        1,786        1,512        6,326        16,111           16,111             16,111
Gross profit..............         348          493          411        2,850         8,565            8,565              8,565
Total operating
  expenses................         601        2,801        5,178       30,887       441,100          441,100            441,100
                            ----------   ----------   ----------   ----------    ----------       ----------         ----------
Operating loss............        (253)      (2,308)      (4,767)     (28,037)     (432,535)        (432,535)          (432,535)
                            ----------   ----------   ----------   ----------    ----------       ----------         ----------
Net loss..................  $     (417)  $   (2,747)  $   (4,693)  $  (30,691)   $ (435,021)      $ (435,021)        $ (449,461)
                            ==========   ==========   ==========   ==========    ==========       ==========         ==========
Pro forma net loss per
  share-basic and
  diluted.................  $    (0.04)  $    (0.22)  $    (0.29)  $    (1.45)   $   (16.90)      $   (15.41)        $   (15.92)
                            ==========   ==========   ==========   ==========    ==========       ==========         ==========
Pro forma weighted average
  shares used in computing
  net loss per share-basic
  and diluted.............  10,554,795   12,655,901   15,916,383   21,207,225    25,744,511       28,235,730         28,235,730
                            ==========   ==========   ==========   ==========    ==========       ==========         ==========
</TABLE>

<TABLE>
<CAPTION>
                                                                           AS OF DECEMBER 31, 1999
                                                         ------------------------------------------------------------
                                                                                        PRO FORMA
                                                                    -------------------------------------------------
                                                                                                       ACQUISITIONS,
                                                                                   ACQUISITIONS AND    COMMON STOCK
                                                                                     COMMON STOCK     AND CONVERTIBLE
                                                          ACTUAL    ACQUISITIONS       OFFERING       NOTES OFFERINGS
                                                         --------   ------------   ----------------   ---------------
<S>                                                      <C>        <C>            <C>                <C>
CONSOLIDATED BALANCE SHEET DATA:
  Cash and cash equivalents............................  $ 78,542    $   47,719       $  354,288         $  547,088
  Working capital......................................    83,128        37,064          362,608            555,408
  Total assets.........................................   102,534     1,244,067        1,677,637          1,877,637
  Total debt...........................................        --        19,337              362            200,362
  Stockholders' equity.................................    98,342     1,219,145        1,671,690          1,671,690
</TABLE>

                                        8
<PAGE>   11

                                  RISK FACTORS

     Investing in our common stock involves risks. You should carefully consider
the following risks together with the other information contained in this
prospectus before deciding to buy our common stock.

OUR FUTURE RESULTS ARE UNCERTAIN BECAUSE OUR HISTORICAL REVENUE WAS DERIVED FROM
SERVICES OTHER THAN THOSE WE EXPECT TO BE THE FOCUS OF OUR BUSINESS IN THE
FUTURE.

     We only have a limited history selling our current services on which you
can evaluate our business, financial condition and operating results. Although
we commenced operations in January 1996, until March 1997 all of our revenue
came from engineering services and not from monthly service subscriptions or
software licensing which we now provide and which will be our focus in the
future. In 1997, 91.0% of our revenue was from engineering services and 9.0% was
from subscriber revenue. In 1998, 63.7% of our revenue was from engineering
services and 36.3% was from subscriber revenue. In 1999, 41.0% of our revenue
was from engineering services and 59.0% was from subscriber revenue. In 1999, on
a pro forma basis including Mobeo, LocusOne and our pending acquisition of
Riverbed, 16.1% of our revenue was from engineering services, 69.5% was from
subscriber revenue, and 14.4% was from software and related services revenue. We
have not had any AIM licensing revenue. In addition, our monthly service
subscriptions have come exclusively from subscriptions to our financial data and
online trading services, and our strategy includes development of services in
other industries. Because of this change in focus and our recent and pending
acquisitions, you should not rely on our past performance to evaluate our future
performance.

WE HAVE HISTORICALLY INCURRED LOSSES AND THESE LOSSES MAY INCREASE IN THE
FUTURE.

     We reported net losses of $2.7 million, $4.7 million and $30.7 million for
the years ended December 31, 1997, 1998 and 1999, respectively, and a net loss
of $435.0 million for the year ended December 31, 1999 on a pro forma basis
including the acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed. Our amortization of intangible assets and option and warrant expense
has grown significantly as a result of recent acquisitions. In addition, we
expect to continue to incur significant sales and marketing, systems development
and administrative expenses. Therefore, we will need to generate significant
revenue to become profitable and sustain profitability on a quarterly or annual
basis. We expect to continue to incur significant losses for the foreseeable
future. As a result, we may not be able to achieve profitability on a quarterly
or annual basis.

THERE IS NO ESTABLISHED MARKET FOR OUR FINANCIAL DATA AND OTHER SERVICES AND WE
MAY NOT BE ABLE TO SELL ENOUGH OF OUR SERVICES TO BECOME PROFITABLE.

     The markets for wireless data and transaction services are still emerging
and continued growth in demand for and acceptance of these services remains
uncertain. Current barriers to market acceptance of these services include cost,
reliability, functionality and ease of use. We cannot be certain that these
barriers will be overcome. We are currently developing financial trading
services for TD Waterhouse Investor Services, Inc. and Bear, Stearns & Co. Inc.
pursuant to preliminary agreements with these parties. We cannot assure you that
these parties will enter into contracts for our services or that products
developed for our other customers will result in revenue. Our competitors may
develop alternative wireless data communications systems that gain broader
market acceptance than our systems. If the market for our services does not
grow, or grows more slowly than we currently anticipate, we may not be able to
attract customers for our services and our revenues would be adversely affected.

                                        9
<PAGE>   12

OUR RECENT AND PENDING ACQUISITIONS, INVESTMENTS AND STRATEGIC ALLIANCES MAY NOT
DELIVER THE VALUE WE PAID OR WILL PAY FOR THEM AND MAY RESULT IN EXCESSIVE
EXPENSES IF WE DO NOT SUCCESSFULLY INTEGRATE THEM, OR IF THE COSTS AND
MANAGEMENT RESOURCES WE EXPEND IN CONNECTION WITH THE INTEGRATIONS EXCEED OUR
EXPECTATIONS.

     We expect that our recent and pending acquisitions, investments and
strategic alliances and any acquisitions, investments or strategic alliances we
may pursue in the future will have a continuing, significant impact on our
business, financial condition and operating results. The value of these
transactions may be less than the amount we paid for them or invested if there
is:

     - a decline of their position in the respective markets they serve; or

     - a decline in general of the markets they serve.

     The expenses associated with these transactions may be greater and their
revenue may be smaller than expected if:

     - we fail to assimilate the acquired assets with our pre-existing business;

     - we lose key employees of these companies or Aether as a result of the
       acquisitions;

     - our management's attention is diverted by other business concerns; or

     - we assume unanticipated liabilities related to the acquired assets.

     In addition, the companies we have acquired or invested in or may acquire
or invest in are subject to each of the business risks we describe in this
section, and if they incur any of these risks the businesses may not be as
valuable as the amount we paid. Further, we cannot guarantee that we will
realize the benefits or strategic objectives we are seeking to obtain by
acquiring these companies. In addition, we cannot assure you that our various
pending acquisitions, investments and strategic alliances will be completed on
the terms we describe, or at all.

WE MAY NOT ACHIEVE PROFITABILITY IF WE ARE UNABLE TO MAINTAIN, IMPROVE AND
DEVELOP THE WIRELESS DATA SERVICES WE OFFER.

     We believe that our future business prospects depend in part on our ability
to maintain and improve our current services and to develop new ones on a timely
basis. Our services will have to achieve market acceptance, maintain
technological competitiveness and meet an expanding range of customer
requirements. As a result of the complexities inherent in our service offerings,
major new wireless data services and service enhancements require long
development and testing periods. We may experience difficulties that could delay
or prevent the successful development, introduction or marketing of new services
and service enhancements. Additionally, our new services and service
enhancements may not achieve market acceptance. If we cannot effectively develop
and improve services we may not be able to recover our fixed costs or otherwise
become profitable.

IF WE DO NOT RESPOND EFFECTIVELY AND ON A TIMELY BASIS TO RAPID TECHNOLOGICAL
CHANGE, OUR SERVICES MAY BECOME OBSOLETE AND WE MAY LOSE SALES.

     The wireless and data communications industries are characterized by
rapidly changing technologies, industry standards, customer needs and
competition, as well as by frequent new product and service introductions. Our
services are integrated with wireless handheld devices and the computer systems
of our corporate customers. Our services must also be compatible with the data
networks of wireless carriers. We must respond to technological changes
affecting both our customers and suppliers. We may not be successful in
developing and marketing, on a timely and cost-effective basis, new services
that respond to technological changes, evolving industry standards or changing
customer requirements. Our ability to grow

                                       10
<PAGE>   13

and achieve profitability will depend, in part, on our ability to accomplish all
of the following in a timely and cost-effective manner:

     - effectively use and integrate new wireless and data technologies;

     - continue to develop our technical expertise;

     - enhance our wireless data, engineering and system design services;

     - develop applications for new wireless networks; and

     - influence and respond to emerging industry standards and other changes.

WE DEPEND UPON WIRELESS NETWORKS OWNED AND CONTROLLED BY OTHERS. IF WE DO NOT
HAVE CONTINUED ACCESS TO SUFFICIENT CAPACITY ON RELIABLE NETWORKS, WE MAY BE
UNABLE TO DELIVER SERVICES AND OUR SALES COULD DECREASE.

     Our ability to grow and achieve profitability partly depends on our ability
to buy sufficient capacity on the networks of wireless carriers such as AT&T
Wireless Services or Bell Atlantic Mobile and on the reliability and security of
their systems. All of our services are delivered using airtime purchased from
third parties. We depend on these companies to provide uninterrupted and "bug
free" service and would not be able to satisfy our customers' needs if they
failed to provide the required capacity or needed level of service. In addition,
our expenses would increase and our profitability could be materially adversely
affected if wireless carriers were to increase the prices of their services. Our
existing agreements with the wireless carriers generally have one-year terms.
Some of these wireless carriers are, or could become, our competitors and if
they compete with us they may refuse to provide us with their services.

OUR FAILURE TO DEVELOP RECOGNITION FOR THE AETHER BRAND COULD PREVENT US FROM
ACHIEVING A PROFITABLE LEVEL OF SALES.

     Our sales and marketing activities to date have been limited. Our sales and
marketing expenses were $840,455 for the year ended December 31, 1998 and $2.1
million for 1999. We intend to increase the market presence of our brand over
time, which will require us to substantially increase the amount we spend on
sales and marketing. We expect to spend an estimated $25 million in 2000 on
sales and marketing. We have applied for, but have not received, federal
trademark registrations for the names "Aether," "Aether Systems" and "AIM," and
we may not be able to use these names effectively or at all if we fail to obtain
such registrations due to conflicting marks or otherwise. As a result of our
recent acquisitions of Mobeo and LocusOne and our pending acquisition of
Riverbed, we expect to market our acquired products and services under their
existing brands. We may lose existing customers or fail to attract new customers
if these brands are not well received by our customers, if our marketing efforts
are not productive, if we are otherwise unsuccessful in increasing our brand
awareness or if our competition has greater brand recognition.

WE DEPEND ON THIRD PARTIES FOR THE MARKETING AND SALES OF SOME OF OUR SERVICES.
IF THE MARKETING EFFORTS OF THESE THIRD PARTIES ARE NOT EFFECTIVE, WE MAY NOT
ACHIEVE A PROFITABLE LEVEL OF SALES.

     We rely substantially on the efforts of others to market and sell some of
our wireless data communications services, in particular the online trading
services we have developed for Morgan Stanley Dean Witter Online and are
developing for Charles Schwab and other financial institutions. We believe that
third parties paid over $380,000 in marketing expenses in 1999 related to our
products, which represented 15% of sales and marketing expenses incurred in
connection with our services. We cannot control whether or how these third
parties who sell and market our services will perform their obligations to
market our services. If these third parties fail to market our services or their
efforts fail to result in new customers, we may be unable to attract new
customers and our revenue could be adversely effected.

                                       11
<PAGE>   14

WE MAY FAIL TO SUPPORT OUR ANTICIPATED GROWTH IN OPERATIONS WHICH COULD REDUCE
DEMAND FOR OUR SERVICES AND MATERIALLY ADVERSELY AFFECT OUR REVENUE.

     Our business strategy is based on the assumption that the number of
subscribers to our services, the amount of information they want to receive and
the number of services we offer will all increase. We must continue to develop
and expand our systems and operations to accommodate this growth. The expansion
and adaptation of our customer service and network operations center requires
substantial financial, operational and management resources. We may be unable to
expand our operations for one or more of the following reasons:

     - we may not be able to locate or hire at reasonable compensation rates
       qualified engineers and other employees necessary to expand our capacity;

     - we may not be able to obtain the hardware necessary to expand our
       capacity;

     - we may not be able to expand our billing and other related support
       systems; and

     - we may not be able to obtain sufficient additional capacity from wireless
       carriers.

     Due to the limited deployment of our services to date, the ability of our
systems and operations to connect and manage a substantially larger number of
customers while maintaining superior performance is unknown. Any failure on our
part to develop and maintain our wireless data services as we experience rapid
growth could significantly reduce demand for our services and materially
adversely affect our revenue.

WE DEPEND ON RECRUITING AND RETAINING KEY MANAGEMENT AND TECHNICAL PERSONNEL
WITH WIRELESS DATA AND SOFTWARE EXPERIENCE AND WE MAY NOT BE ABLE TO DEVELOP NEW
PRODUCTS OR SUPPORT EXISTING PRODUCTS IF WE CANNOT HIRE OR RETAIN QUALIFIED
EMPLOYEES.

     Because of the technical nature of our products and the dynamic market in
which we compete, our performance depends on attracting and retaining key
employees. Competition for qualified personnel in the wireless data and software
industries is intense and finding qualified personnel with experience in both
industries is even more difficult. We believe there are only a limited number of
individuals with the requisite skills in the field of wireless data
communication, and it is becoming increasingly difficult to hire and retain
these persons. Competitors and others have in the past attempted, and may in the
future attempt, to recruit our employees. Each of our engineers has entered into
a non-compete agreement with us for a period of ten months after they leave
Aether. These agreements will not prevent our engineers from leaving or working
for competitors relatively soon after they leave us.

     We currently maintain a key person life insurance policy for David S. Oros,
our chairman, chief executive officer and president. We do not maintain
insurance policies for any of our other employees.

WE MAY NOT HAVE ADEQUATELY PROTECTED OUR INTELLECTUAL PROPERTY RIGHTS, WHICH
COULD ALLOW COMPETITORS TO DEVELOP SIMILAR PRODUCTS USING SIMILAR TECHNOLOGY AND
THUS REDUCE OUR SALES AND REVENUE.

     We have attempted to protect our technology, including the technology we
have obtained or will obtain in our acquisition, through patent, trademark and
copyright protection, as well as through trade secret laws and non-competition
and non-disclosure agreements with key employees. Patents may infringe on valid
patents held by third parties, or patents held by third parties may limit the
scope of any patents we receive. In particular, the patent we expect to acquire
in our acquisition of Riverbed covers a technology that is subject to a number
of patents. In addition, Riverbed has no international patent protection in its
technology. If we are not adequately protected, other companies with sufficient
engineering expertise could quickly develop competing products based on our
intellectual property and reduce our sales and thus our revenue.

                                       12
<PAGE>   15

WE MAY BE SUED BY THIRD PARTIES FOR INFRINGEMENT OF THEIR INTELLECTUAL PROPERTY
RIGHTS AND INCUR COSTS OF DEFENSE AND POSSIBLY ROYALTIES OR LOSE THE RIGHT TO
USE TECHNOLOGY IMPORTANT TO PROVIDING OUR SERVICES.

     The telecommunications and software industries are characterized by the
existence of a large number of patents and frequent litigation based on
allegations of patent infringement or other violations of intellectual property
rights. As the number of participants in our market increases, the possibility
of an intellectual property claim against us could increase. We have received
two claims that we have infringed patents developed by other parties. Although
we believe these claims are without merit, these and any other intellectual
property claims, with or without merit, could be time-consuming and expensive to
litigate or settle, could require us to enter into costly royalty arrangements,
could divert management attention from administering our business and could
preclude us from conducting our business.

WE MAY BE SUBJECT TO LIABILITY FOR TRANSMITTING INFORMATION, AND OUR INSURANCE
COVERAGE MAY BE INADEQUATE TO PROTECT US FROM THIS LIABILITY.

     We may be subject to claims relating to information transmitted over
systems we develop or operate. These claims could take the form of lawsuits for
defamation, negligence, copyright or trademark infringement or other actions
based on the nature and content of the materials. Although we carry general
liability insurance, our insurance may not cover potential claims of this type
or may not be adequate to cover all costs incurred in defense of potential
claims or to indemnify us for all liability that may be imposed.

DISRUPTION OF OUR SERVICES DUE TO ACCIDENTAL OR INTENTIONAL SECURITY BREACHES
MAY HARM OUR REPUTATION CAUSING A LOSS OF SALES AND COULD INCREASE OUR EXPENSES.

     A significant barrier to the growth of wireless data services or
transactions on the Internet or by other electronic means has been the need for
secure transmission of confidential information. Our systems could be disrupted
by unauthorized access, computer viruses and other accidental or intentional
actions. We may incur significant costs to protect against the threat of
security breaches or to alleviate problems caused by such breaches. If a third
party were able to misappropriate our users' personal or proprietary information
or credit card information, we could be subject to claims, litigation or other
potential liabilities that could materially adversely impact our revenue and may
result in the loss of customers.

ANY TYPE OF SYSTEMS FAILURE COULD REDUCE SALES, INCREASE COSTS OR RESULT IN
CLAIMS OF LIABILITY.

     Our existing wireless data services -- TradeRunner, Reuters MarketClip and
its predecessor AirBroker and the Mobeo services -- are dependent on real-time,
continuous feeds from Reuters Selectfeed Plus and others. The ability of our
subscribers to make securities trades through Morgan Stanley Dean Witter Online
requires timely and uninterrupted connections with our wireless network
carriers. Any disruption from our satellite feeds or backup landline feeds could
result in delays in our subscribers' ability to receive information or execute
trades. There can be no assurance that our systems will operate appropriately if
we experience a hardware or software failure or if there is an earthquake, fire
or other natural disaster, a power or telecommunications failure, intentional
disruptions of service by third parties, an act of God or an act of war. A
failure in our systems could cause delays in transmitting data, and as a result
we may lose customers or face litigation that could involve material costs and
distract management from operating our business.

OUR ABILITY TO SELL NEW AND EXISTING SERVICES AT A PROFIT COULD BE IMPAIRED BY
COMPETITORS.

     Intense competition could develop in the market for services we offer. We
developed our software using standard industry development tools. Many of our
agreements with wireless carriers, wireless handheld device manufacturers and
data providers are non-exclusive. Our competitors could develop and use the same
products and services in competition with us. With time and capital, it would be
possible for competitors to replicate our services. Our competitors could
include wireless network carriers such as AT&T Wireless Services and Bell
Atlantic Mobile, software developers such as Microsoft Corporation, 724

                                       13
<PAGE>   16

Solutions Inc. and Phone.com and systems integrators such as International
Business Machines Corporation. Many of our competitors have significantly
greater resources than we do. Furthermore, competitors may develop a different
approach to marketing the services we provide in which subscribers may not be
required to pay for the information provided by our services. Competition could
reduce our market share or force us to lower prices to unprofitable levels.
Additional information regarding our competition is described under
"Business -- Competition" on page 53.

WE MAY LOSE THE OPPORTUNITY TO PURSUE DESIRABLE PROJECTS TO OMNISKY AND THE
COMPANY WE PLAN TO FORM WITH REUTERS.

     David S. Oros, our chairman, chief executive officer and president, also
serves as a director of OmniSky and Janice M. Roberts, one of our directors, is
also a director of OmniSky. OmniSky is a separate business in which we have an
equity interest that is developing applications for wireless access to the
Internet and related applications such as wireless e-mail. David S. Oros will
serve as chairman and interim chief executive officer of our European strategic
alliance with Reuters. This company will be a separate business that will
provide wireless data applications in Europe. Mr. Oros and Ms. Roberts may learn
of business opportunities that are appropriate for OmniSky and us, and Mr. Oros
may learn of business opportunities that are appropriate for our pending
strategic alliance with Reuters and us, and Mr. Oros and Ms. Roberts may not be
required to make those opportunities available to us. If OmniSky or our
strategic alliance with Reuters pursue opportunities that we would have an
interest in pursuing, our business may fail to grow or our existing business may
suffer. Mr. Oros and Ms. Roberts may also have other conflicts of interest with
Aether because of their positions with OmniSky, and OmniSky's contractual
relationships with Aether and 3Com. Mr. Oros may also have other conflicts of
interest with Aether because of his position with the strategic alliance with
Reuters and its contractual relationships with Aether. We describe those
contracts in "Transactions between Aether and its Officers, Directors or
Significant Stockholders -- OmniSky" on page 70.

AN INTERRUPTION IN THE SUPPLY OF PRODUCTS AND SERVICES THAT WE OBTAIN FROM THIRD
PARTIES COULD CAUSE A DECLINE IN SALES OF OUR SERVICES, AND PRODUCTS WE PURCHASE
TO AVOID SHORTAGES MAY BECOME OBSOLETE BEFORE WE CAN USE THEM.

     In designing, developing and supporting our wireless data services, we rely
on wireless carriers, wireless handheld device manufacturers, content providers
and software providers. These suppliers may experience difficulty in supplying
us products or services sufficient to meet our needs or they may terminate or
fail to renew contracts for supplying us these products or services on terms we
find acceptable. Any significant interruption in the supply of any of these
products or services could cause a decline in sales of our services unless and
until we are able to replace the functionality provided by these products and
services. Specifically, Novatel Wireless and Sierra Wireless Inc. are our only
suppliers of wireless modems, which are an integral hardware component of our
services. It can be difficult to obtain these wireless modems and their parts.
Although we have purchased a large supply of these modems, they may become
obsolete before we are able to use them. We also depend on third parties to
deliver and support reliable products, enhance their current products, develop
new products on a timely and cost-effective basis and respond to emerging
industry standards and other technological changes. In addition, we rely on the
ability of our content providers -- Reuters, the New York Stock Exchange, Inc.,
the Chicago Board of Trade, the Nasdaq Stock Market, Inc. and the Options Price
Reporting Authority -- to continue to provide us with uninterrupted access to
the news and financial information we provide to our customers. The failure of
third parties to meet these criteria, or their refusal or failure to deliver the
information for whatever reason, could materially harm our business.

OUR SALES CYCLE IS LONG, AND OUR STOCK PRICE COULD DECLINE IF SALES ARE DELAYED
OR CANCELLED.

     Quarterly fluctuations in our operating performance are exacerbated by the
length of time between our first contact with a business customer and the first
revenue from sales of services to that customer or end users. Because our
services represent a significant investment for our business customers, we spend
a

                                       14
<PAGE>   17

substantial amount of time educating them regarding the use and benefits of our
services and they, in turn, spend a substantial amount of time performing
internal reviews and obtaining capital expenditure approvals before purchasing
our services. As much as a year may elapse between the time we approach a
business customer and the time we begin to deliver services to a customer or end
user. Any delay in sales of our services could cause our quarterly operating
results to vary significantly from projected results, which could cause our
stock price to decline. In addition, we may spend a significant amount of time
and money on a potential customer that ultimately does not purchase our
services.

OUR SALES OF FINANCIAL DATA AND TRADING SERVICES COULD GO DOWN IF THERE IS A
DECLINE IN SECURITIES TRADING.

     In 1999, we earned 59.0% (or 69.5% on a pro forma basis giving effect to
the acquisitions of Mobeo and LocusOne and the pending acquisition of Riverbed)
of our revenue from services that provide financial information and wireless
trading capability. If there is a prolonged decline in the overall level of
securities trading, or online trading in particular, our operating results may
decline. A decline in securities trading may result from:

     - loss of confidence in the reliability or security of online trading
       systems;

     - government regulation of the securities industry or online trading; or

     - a downturn in the stock market.

OUR SOFTWARE MAY CONTAIN DEFECTS OR ERRORS, AND OUR SALES COULD GO DOWN IF THIS
INJURES OUR REPUTATION OR DELAYS SHIPMENTS OF OUR SOFTWARE.

     The AIM package of wireless messaging and software development tools we
develop, and the ScoutWare family of software products we will own at the
closing of the Riverbed acquisition, are complex and must meet the stringent
technical requirements of our customers. We must develop our services quickly to
keep pace with the rapidly changing software and telecommunications markets.
Software as complex as ours is likely to contain undetected errors or defects,
especially when first introduced or when new versions are released. Our software
may not be free from errors or defects after delivery to customers have begun,
which could result in the rejection of our software or services, damage to our
reputation, lost revenue, diverted development resources and increased service
and warranty costs.

UNDISCOVERED YEAR 2000-RELATED COMPUTER PROBLEMS COULD DISRUPT OUR OPERATIONS.

     We believe that software that is incorporated in our products and services
is year 2000 compliant. When the century changed, we experienced no disruption
to our business operations and no product failures as a result of year 2000
compliance issues or otherwise. We may face claims, however, for undiscovered
year 2000 errors in our own products or for year 2000 issues arising from
third-party products that we integrate into our products and services or with
which our systems and products exchange data. If our suppliers, vendors or
distributors fail to timely and completely correct their own year 2000 software,
firmware and hardware problems, or if any of them convert to a system that is
incompatible with our systems, our ability to deliver our products and services
could be disrupted.

THE STOCKHOLDER AGREEMENT AMONG OUR MAJOR STOCKHOLDERS WILL HAVE THE EFFECT OF
ALLOWING THEM TO CONTROL EIGHT OF OUR TWELVE DIRECTORS, WHICH WILL LIMIT THE
ABILITY OF NEW INVESTORS TO INFLUENCE CONTROL OF AETHER.

     NexGen Technologies, L.L.C., Telcom-ATI Investors, L.L.C., Reuters
MarketClip Holdings Sarl, a subsidiary of Reuters Group PLC, and 3Com -- who
together will hold 55.1% of the shares of common stock outstanding following
completion of this offering -- entered into a stockholder agreement that governs
voting for our directors. The agreement provides that each party will vote all
of its shares for two directors nominated by NexGen, two directors nominated by
Telcom-ATI Investors, two directors nominated jointly by NexGen and Telcom-ATI
Investors and one director nominated by each of Reuters and 3Com. As a result,
eight directors of our board are effectively chosen by these major stockholders.
As we currently have authorized only 12 directors, the voting rights of our
stockholders other than these major stockholders effectively apply to only

                                       15
<PAGE>   18

four of our directors. In addition to its effect on the voting rights of our new
investors, the stockholder agreement could have the effect of delaying or
preventing a change in control.

WE MAY NEED ADDITIONAL CAPITAL AND WE MAY NOT BE ABLE TO OBTAIN IT, WHICH COULD
PREVENT US FROM CARRYING OUT OUR BUSINESS STRATEGY.

     We currently anticipate that our available cash resources combined with the
net proceeds from this offering and the concurrent offering of convertible notes
will be sufficient to fund our operating needs for at least the next 12 months,
including the expansion of our sales and marketing program and any acquisitions
we may pursue in the next 12 months. Thereafter, we expect to require additional
financing in an amount that we cannot determine at this time. We do not have any
bank credit facility or other working capital credit line under which we may
borrow funds for working capital or other general corporate purposes. If our
plans or assumptions change or are inaccurate, we may be required to seek
capital sooner than anticipated. We may need to raise funds through public or
private debt or equity financings.

     If funds are raised through the issuance of equity securities, the
percentage ownership of our then-current stockholders may be reduced and the
holders of new equity securities may have rights, preferences or privileges
senior to those of the holders of our common stock. If additional funds are
raised through a bank credit facility or the issuance of debt securities, the
holder of this indebtedness would have rights senior to the rights of the
holders of our common stock and the terms of this indebtedness could impose
restrictions on our operations. If we need to raise additional funds, we may not
be able to do so on terms favorable to us, or at all. If we cannot raise
adequate funds on acceptable terms, we may not be able to continue to fund our
operations.

     We may not be able to complete the proposed subordinated convertible notes
offering being conducted concurrently with this offering. Failure to complete
the notes offering may increase our need for financing.

NEW LAWS AND REGULATIONS THAT IMPACT OUR INDUSTRY COULD INCREASE OUR COSTS OR
REDUCE OUR OPPORTUNITIES TO EARN REVENUE.

     We are not currently subject to direct regulation by the Federal
Communications Commission or any other governmental agency, other than
regulations applicable to businesses in general. However, in the future, we may
become subject to regulation by the FCC or another regulatory agency. In
addition, the wireless carriers who supply us airtime are subject to regulation
by the FCC and regulations that affect them could increase our costs or reduce
our ability to continue selling and supporting our services.

OUR STOCK PRICE, LIKE THAT OF MANY TECHNOLOGY COMPANIES, HAS BEEN, AND MAY
CONTINUE TO BE, VOLATILE.

     The market price of our common stock has been highly volatile and is likely
to continue to be highly volatile. The trading price of our common stock has
increased significantly from our initial offering price of $16.00 per share on
October 20, 1999. We are involved in a highly visible, rapidly changing industry
and stock prices in our and similar industries have risen and fallen in response
to a variety of factors, including:

     - announcements of new wireless data communications technologies and new
       providers of wireless data communications;

     - acquisitions of or strategic alliances among providers of wireless data
       communications;

     - changes in recommendations by securities analysts regarding the results
       or prospects of providers of wireless data communications; and

     - changes in investor perceptions of the acceptance or profitability of
       wireless data communications.

WE HAVE ANTI-TAKEOVER DEFENSES THAT COULD DELAY OR PREVENT AN ACQUISITION AND
COULD ADVERSELY AFFECT THE PRICE OF OUR COMMON STOCK.

     Provisions of our certificate of incorporation and bylaws and provisions of
Delaware law could delay, defer or prevent an acquisition or change of control
of Aether or otherwise adversely affect the price of our common stock. For
example, our bylaws limit the ability of stockholders to call a special meeting.
Our

                                       16
<PAGE>   19

certificate of incorporation also permits our board to issue shares of preferred
stock without stockholder approval which means that the board could issue shares
with special voting rights or other provisions that could deter a takeover. In
addition to delaying or preventing an acquisition, the issuance of a substantial
number of preferred shares could adversely affect the price of the common stock.
Please refer to "Description of Capital Stock" on page 76 for a more detailed
discussion of these provisions.

UPON COMPLETION OF THIS OFFERING, YOU WILL EXPERIENCE DILUTION.

     Our tangible assets are readily identified assets like property, equipment,
cash, securities and accounts receivable. The value of these assets on our pro
forma balance sheet minus the value of our liabilities equals $14.22 per share,
giving effect to the acquisition of LocusOne and the pending acquisition of
Riverbed and the completion of this offering and the concurrent note offering.
The offering price (assuming an offering price of $203 per share) exceeds this
amount by $188.78 per share. Therefore, you will be paying more for a share of
stock than the value reflected in our accounts of tangible assets for that
share. If we were forced to sell all our assets and distribute all the proceeds,
you would not recover the amount you paid for shares unless we can sell the
assets for more than the value we report for our tangible assets. We also have
outstanding a large number of stock options and warrants to purchase common
stock with exercise prices significantly below the price of shares in this
offering. You will experience further dilution to the extent these options or
warrants are exercised.

SHARES ELIGIBLE FOR FUTURE SALE BY OUR CURRENT STOCKHOLDERS MAY DEPRESS OUR
SHARE PRICE.

     After this offering, we will have outstanding 34,509,687 shares of common
stock, including the 4,537,286 shares to be issued to former shareholders of
Riverbed. Sales of a substantial number of our shares of common stock in the
public market following this offering -- or the expectation of such sales --
could cause the market price of our common stock to drop. All the shares sold in
this offering will be, and the shares sold in our initial public offering are,
freely tradable. An additional 24,114,750 shares will be available for sale in
the public markets as follows:

<TABLE>
<CAPTION>
               DATE OF AVAILABILITY FOR SALE                    NUMBER OF SHARES
               -----------------------------                    ----------------
<S>                                                             <C>
               (90 days after the date of this prospectus)....       19,250
October 26, 2000..............................................   19,671,646
At various times thereafter upon the expiration of one-year
  holding periods.............................................    4,423,854
</TABLE>

     Of these shares, 24,095,500 shares are subject to a limitation on the
number of shares that can be sold in any three-month period. We have agreed,
however, to register the resale of substantially all of these shares upon demand
beginning October 27, 2000.

     We filed a registration statement to register all shares of common stock
that were issued to our employees under our equity incentive plan and intend to
file future registration statements. Shares issued upon exercise of stock
options will be eligible for resale in the public market without restriction. As
of February 15, 2000, options and warrants to purchase 4,012,574 shares of our
common stock were issued and outstanding and we were obligated to issue options
for an additional 862,480 shares in connection with our pending acquisition of
Riverbed.

DEBT SERVICE OBLIGATIONS MAY ADVERSELY AFFECT OUR CASH FLOW.

     Concurrently with this offering, we anticipate offering convertible
subordinated notes in an aggregate principal amount of $200 million, or $230
million if the over-allotment option granted to the underwriters in connection
with the notes offering is exercised in full. If the notes offering is completed
as planned, we will have substantial amounts of outstanding indebtedness,
primarily consisting of the notes. As a result of this indebtedness, we will be
obligated to make principal and interest payments. There is the possibility that
we may be unable to generate cash sufficient to pay the principal of, interest
on and other amounts due in respect of our indebtedness when due. We may also
obtain additional long-term debt and working

                                       17
<PAGE>   20

capital lines of credit to meet future financing needs. There can be no
assurance that additional financing arrangements will be available on
commercially reasonable terms or at all.

WE MAY HAVE CONTINGENT LIABILITY ARISING OUT OF A POSSIBLE VIOLATION OF THE
SECURITIES ACT OF 1933 IN CONNECTION WITH A LETTER SENT TO EMPLOYEES IN THE
DIRECTED SHARE PROGRAM AT THE TIME OF OUR INITIAL PUBLIC OFFERING.

     As part of our initial public offering in October 1999, we decided that
each of our employees, officers and directors should have the opportunity to
purchase up to 2,000 shares of common stock as part of a directed share program,
on the same terms as all other shares offered by the prospectus, but that each
person could choose to direct all or a part of the 2,000 shares to members of
his or her immediate family. In order to coordinate this program, we sent a
letter to approximately 90 employees, officers and directors we had designated
as potential offerees of up to 390,000 shares of common stock and asked them to
provide us with information for mailing purposes, including an estimate of the
number of shares that they would want to be given the opportunity to purchase
and to have their immediate family members provide the same information. Our
letter was not accompanied by a preliminary prospectus and may have constituted
a prospectus that does not meet the requirements of the Securities Act of 1933.
If the mailing of these original materials did constitute a violation of the
Securities Act of 1933, the recipients of the letter who purchased common stock
in our initial public offering and continue to own those shares could have the
right until October 26, 2000 to obtain recovery of the consideration paid in
connection with their purchase of common stock or, if they had already sold the
stock, sue us for damages resulting from their purchase of common stock. If all
of the recipients of the letter still hold shares they purchased in the initial
public offering, these refunds or damages could total up to approximately $6.2
million, based on the initial public offering price of $16.00 per share, in the
event that investors suffer a total loss of their investment before they sold
the shares or the relevant limitations period expired and seek refunds or
damages. If this were to occur, our business, results of operations and
financial condition could suffer.

                                       18
<PAGE>   21

                           FORWARD-LOOKING STATEMENTS

     This prospectus includes forward-looking statements within the meaning of
Section 27A of the Securities Act and Section 21E of the Securities Exchange
Act. These include projections about the industry contained on pages 37 to 38.
We have based these forward-looking statements on our current expectations and
projections about future events. In some cases, you can identify forward-looking
statements by terminology such as "may," "will," "should," "could," "pending,"
"potential," "continue," "expects," "anticipates," "intends," "plans,"
"believes," "predicts," "estimates" and similar expressions, although not all
forward-looking statements are identified by these words. These forward-looking
statements are subject to a number of risks, uncertainties and assumptions about
Aether, including those we describe in the "Risk Factors" section of this
prospectus. In light of these risks, uncertainties and assumptions, the
forward-looking events discussed in this prospectus might not occur. We
undertake no obligation to publicly update or revise any forward-looking
statements, whether as a result of new information, future events or otherwise.

     We use market data and industry forecasts and projections throughout this
prospectus, which we have obtained from internal surveys, market research,
publicly available information and industry publications. Industry publications
generally state that the information they provide has been obtained from sources
believed to be reliable, but that the accuracy and completeness of such
information is not guaranteed. The forecasts and projections are based on
industry surveys and the preparers' experience in the industry and there is no
assurance that any of the projected amounts will be achieved. Similarly, we
believe that the surveys and market research we or others have performed are
reliable, but we have not independently verified this information. Neither we
nor any of the underwriters represents that any such information is accurate.

                                       19
<PAGE>   22

                                USE OF PROCEEDS

     We expect to receive approximately $452.5 million in net proceeds from the
sale of 2,346,219 shares of common stock, assuming an offering price of $203, by
Aether in this offering ($483.4 million if the underwriters' over-allotment
option is exercised in full) after deduction of estimated underwriting discounts
and commissions and estimated offering expenses payable by us and the exercise
of options to purchase 145,000 shares by the selling stockholders. We will not
receive any proceeds from the 653,781 shares sold by selling stockholders in the
offering. The net proceeds to us from the concurrent convertible notes offering
are expected to be approximately $192.8 million ($221.9 million if the
underwriters' over-allotment option is exercised in full) after deduction of
estimated underwriting discounts and commissions and estimated offering expenses
payable by us.

     We currently intend to use $100 million of the proceeds of this offering
and the concurrent notes offering to fund our European strategic alliance with
Reuters, $19 million to repay indebtedness incurred in connection with the
LocusOne acquisition, $17 million to acquire 9.9% of the stock of Metrocall, $10
million to acquire our 27.5% interest in Inciscent and an estimated $25 million
to fund sales and marketing activities. We have not determined the use of the
remaining proceeds of this offering and the concurrent notes offering, but we
expect to use some portion of the proceeds to provide the cash portion of
acquisitions and strategic investments we may identify in the future that
advance our strategy. The offering will also create a larger public float for
our common stock and allow for the orderly liquidation of investments made by
some stockholders.

     Pending these uses, the net proceeds of these offerings will be invested in
short-term, investment grade, interest-bearing instruments.

                          PRICE RANGE OF COMMON STOCK

     Our common stock has been quoted on the Nasdaq National Market under the
symbol "AETH" since our initial public offering on October 20, 1999. Prior to
that time, there was no public market for the common stock. The following table
sets forth, for the periods indicated, the high and low prices per share of the
common stock as reported on the Nasdaq National Market.

<TABLE>
<CAPTION>
                                                              HIGH    LOW
                                                              ----    ---
<S>                                                           <C>     <C>
1999
Fourth Quarter (since October 20, 1999).....................  $ 89 3/8 $41 1/8
2000
First Quarter (through February 18, 2000)...................  $250    $73
</TABLE>

     On February 18, 2000 the reported last sale price of the common stock on
the Nasdaq National Market was $203. As of February 17, 2000 there were
approximately 19 holders of record of our common stock.

                                DIVIDEND POLICY

     We have never declared or paid any cash dividends on our capital stock nor,
when we were organized as a limited liability company, have we made any
distributions to our members. We currently intend to retain earnings, if any, to
support the development of our business and do not anticipate paying cash
dividends in the foreseeable future. Payment of future dividends, if any, will
be at the discretion of our board of directors after taking into account factors
such as our financial condition, operating results and current and anticipated
cash needs.

                                       20
<PAGE>   23

                              CONCURRENT OFFERING

     The convertible notes to be offered in the concurrent offering will be in
an aggregate principal amount of $200 million, excluding $30 million principal
amount subject to an over-allotment option. The convertible notes will be due on
          2005. Interest will accrue on the convertible notes at the rate of   %
per year on the principal amount, payable semiannually in arrears on      and
       of each year commencing on           2005. The convertible notes are
convertible at the option of the holder into common stock. The initial
conversion price is $     per share, which is equal to a conversion rate of
shares per $1,000 principal amount of notes, subject to adjustment. We may
redeem some or all of the notes at any time before           , 2003 if the
closing price of our common stock has exceeded 150% of the conversion price, and
at any time on or after           , 2003 at redemption prices that vary
depending on the date of redemption. The convertible notes will be unsecured and
will be subordinated to our existing and future senior indebtedness. The
convertible notes will be effectively subordinated to the indebtedness and other
obligations of our subsidiaries. The indenture relating to the convertible notes
does not restrict the incurrence by us and our subsidiaries of debt or other
obligations.

                                       21
<PAGE>   24

                                 CAPITALIZATION

     The table below sets forth the following information as of December 31,
1999:

          - our actual capitalization;

          - our pro forma capitalization giving effect to the acquisition of
            LocusOne and the pending acquisition of Riverbed as if completed on
            December 31, 1999;

          - our pro forma capitalization giving effect to the acquisitions
            described above and the sale of 2,346,219 shares of common stock in
            this offering and the exercise of options to purchase 145,000 shares
            by the selling stockholders; and

          - our pro forma capitalization giving effect to the acquisitions
            described above, the sale of shares in this offering and the
            issuance and sale of $200 million of our      % convertible
            subordinated notes due 2005 in the concurrent offering.

     The table below includes deductions for estimated underwriting discounts
and commissions, and for estimated offering expenses in connection with this
offering and the concurrent offering of convertible notes as applicable.

     Actual common stock data are as of December 31, 1999 and exclude:

          - 3,620,838 shares issuable upon exercise of options to purchase
            shares of common stock issued, or to be issued, in connection with
            our pending acquisition of Riverbed, under our equity incentive plan
            at a weighted average exercise price of $6.76 per share;

          - 1,175,000 shares issuable upon exercise of warrants exercisable at a
            weighted average exercise price of $1.96 per share; and

          - 893,665 shares of common stock issuable upon exercise of warrants
            with an exercise price of $.01 per share.

     This table should be read in conjunction with our consolidated financial
statements and the notes thereto and "Management's Discussion and Analysis of
Financial Condition and Results of Operations" beginning on page 27. Details
regarding pro forma adjustments are set forth in the Unaudited Pro Forma
Condensed Consolidated Financial Information beginning on page F-44.

                                       22
<PAGE>   25

<TABLE>
<CAPTION>
                                                                AS OF DECEMBER 31, 1999
                                     -----------------------------------------------------------------------------
                                                                              PRO FORMA
                                                    --------------------------------------------------------------
                                                                                                 ACQUISITIONS,
                                                                                                    COMMON
                                                                       ACQUISITIONS AND      STOCK AND CONVERTIBLE
                                        ACTUAL       ACQUISITIONS    COMMON STOCK OFFERING    NOTES OFFERINGS(1)
                                     ------------   --------------   ---------------------   ---------------------
<S>                                  <C>            <C>              <C>                     <C>
Notes payable, current.............  $         --   $   19,095,600      $      120,578          $      120,578
Notes payable long term............            --          241,155             241,155                 241,155
Convertible subordinated notes.....            --               --                  --             200,000,000
                                     ------------   --------------      --------------          --------------
         Total debt................            --       19,336,755             361,733             200,361,733
                                     ------------   --------------      --------------          --------------
Stockholders' equity:
  Preferred stock, $0.01 par value;
    1,000,000 shares authorized; 0
    shares issued and
    outstanding....................            --               --                  --                      --
  Common stock, $0.01 par value;
    75,000,000 shares authorized;
    shares issued and outstanding:
    actual, 27,154,398;
    acquisitions, 31,691,684;
    acquisitions and common stock
    offering, 34,182,903; and
    acquisitions, common stock and
    convertible notes offering,
    34,182,903.....................       271,543          316,916             341,829                 341,829
  Additional paid-in-capital.......   120,892,478    1,241,650,105       1,694,169,382           1,694,169,382
  Accumulated deficit..............   (22,613,640)     (22,613,640)        (22,613,640)            (22,613,640)
  Notes receivable from
    stockholder....................      (137,879)        (137,879)           (137,879)               (137,879)
  Unrealized loss on investments
    available for sale.............       (70,069)         (70,069)            (70,069)                (70,069)
                                     ------------   --------------      --------------          --------------
         Total stockholders'
           equity..................    98,342,433    1,219,145,433       1,671,689,623           1,671,689,623
                                     ------------   --------------      --------------          --------------
         Total capitalization......  $ 98,342,433   $1,238,482,188      $1,672,051,356          $1,872,051,356
                                     ============   ==============      ==============          ==============
</TABLE>

- ---------------

(1) Completion of the convertible notes offering is not a condition to the
    completion of this offering.

                                       23
<PAGE>   26

                                    DILUTION

     If you invest in our shares of common stock, your interest will be diluted
by the amount of the difference between the public offering price per share of
common stock and the pro forma as adjusted net tangible book value per share of
common stock after this offering.

     Our pro forma net tangible book value as of December 31, 1999 was $40.7
million, or $1.29 per share of common stock, after giving effect to the
acquisition of LocusOne and the pending acquisition of Riverbed.

     Pro forma net tangible book value per share is equal to our total tangible
assets less total liabilities, divided by the number of outstanding shares of
common stock.

     After giving effect to our sale of 2,346,219 shares of common stock in this
offering at an assumed offering price of $203 per share of common stock, the
exercise of options to purchase 145,000 shares by the selling stockholders, and
our concurrent offering of an aggregate principal amount of $200 million in
convertible notes, and after deducting the commissions and estimated offering
expenses for these offerings, our as adjusted pro forma net tangible book value
as of December 31, 1999 would have been $486.1 million, or $14.22 per share of
common stock. This figure represents an immediate increase in net tangible book
value of $12.93 per share of common stock to existing stockholders and an
immediate dilution of $188.78 per share of common stock to new investors. The
following table illustrates this per share dilution to new investors:

<TABLE>
<S>                                                           <C>       <C>
Assumed offering price per share............................            $203.00

  Pro forma net tangible book value per share as of December
     31, 1999...............................................  $  1.29
  Increase per share to existing stockholders attributable
     to the offerings.......................................  $ 12.93
                                                              -------
As adjusted pro forma net tangible book value per share
  after the offerings.......................................            $ 14.22
                                                                        -------
Dilution per share to new investors in this offering........            $188.78
                                                                        =======
</TABLE>

     As of December 31, 1999, we had outstanding options to purchase 2,758,358
shares under our equity incentive plan at a weighted average exercise price of
$5.66 and warrants to purchase 1,175,000 shares at a weighted average exercise
price of $1.96 per share. We issued options to purchase 308,500 shares in the
LocusOne acquisition at a weighted average exercise price of $92.00 per share.
We expect to issue options to purchase approximately 862,480 shares at a
weighted average exercise price of $10.30 per share when we complete our
acquisition of Riverbed. In addition, we expect to have options to purchase
approximately 3,170,765 million additional shares available for future grant
under our equity incentive plan, assuming completion of the Riverbed acquisition
and this offering. If the option holders exercise these outstanding options, or
any options we grant in the future, there will be further dilution to new
investors.

                                       24
<PAGE>   27

                      SELECTED CONSOLIDATED FINANCIAL DATA
               (in thousands, except share and per share amounts)

     The table that follows presents portions of our consolidated financial
statements and is not complete. You should read the following selected
consolidated financial data together with our consolidated financial statements
and related notes and with "Management's Discussion and Analysis of Financial
Condition and Results of Operations" included elsewhere in this prospectus. The
consolidated statement of operations data for the years ended December 31, 1997,
1998 and 1999, and the consolidated balance sheet data as of December 31, 1998
and 1999, are derived from our consolidated financial statements, which have
been audited by KPMG LLP, independent auditors, and which are included in this
prospectus beginning on page F-1. The consolidated statement of operations data
for the year ended December 31, 1996 and the consolidated balance sheet data as
of December 31, 1996 and 1997 are derived from audited financial statements that
do not appear in this prospectus. The historical results presented below are not
necessarily indicative of the results to be expected for any future fiscal year.
See "Management's Discussion and Analysis of Financial Condition and Results of
Operations" beginning on page 27.

     The pro forma consolidated financial information gives effect to (i) the
Mobeo and LocusOne acquisitions and the pending acquisition of Riverbed, (ii)
this offering of common stock and the application of the net proceeds as
described in "Use of Proceeds" on page 20 and (iii) the sale of $200 million of
our convertible notes in a concurrent public offering and the application of the
net proceeds as described in "Use of Proceeds" on page 20. The pro forma net
loss per share information gives effect to our conversion from a limited
liability company to a corporation immediately prior to our initial public
offering.

     We have provided the pro forma consolidated financial information for
informational purposes only and you should not assume that our results would
actually have been as shown if we had acquired Mobeo, LocusOne and Riverbed or
completed the offerings on the assumed dates, or that the information projects
what our results will be as a result of the acquisitions or if we complete the
offerings. The pro forma consolidated statement of operations information
assumes that the transactions occurred on January 1, 1999, and the pro forma
consolidated balance sheet information assumes that the transactions occurred on
December 31, 1999. See our, Mobeo's and Riverbed's financial statements and
notes to those statements included in this prospectus beginning on page F-1.

                                       25
<PAGE>   28
<TABLE>
<CAPTION>
                                                     YEAR ENDED DECEMBER 31,
                               -------------------------------------------------------------------
                                                                                      1999 PRO FORMA
                                                                                      ------------

                                                    HISTORICAL
                               ----------------------------------------------------
                                  1996         1997          1998          1999       ACQUISITIONS
                               ----------   -----------   -----------   -----------   ------------
<S>                            <C>          <C>           <C>           <C>           <C>
CONSOLIDATED STATEMENT OF
  OPERATIONS DATA:
Revenue:
  Subscriber revenue.........  $       --   $       161   $       549   $     3,732   $    11,200
  Engineering services
    revenue..................       1,355         1,625           963         2,594         2,594
  Software and related
    services revenue.........          --            --            --            --         2,317
                               ----------   -----------   -----------   -----------   -----------
      Total revenue..........       1,355         1,786         1,512         6,326        16,111
  Cost of subscriber
    revenue..................          --           447           797         2,110         4,639
  Cost of engineering
    services revenue.........  1,007.....           846           304         1,366         1,366
  Cost of software and
    related services
    revenue..................          --            --            --            --         1,541
                               ----------   -----------   -----------   -----------   -----------
      Total cost of
         revenue.............       1,007         1,293         1,101         3,476         7,546
                               ----------   -----------   -----------   -----------   -----------
      Gross profit...........         348           493           411         2,850         8,565
Operating expenses:
  Research and development...         161           734         1,267         2,614         5,481
  General and
    administrative...........         395         1,505         2,773         5,891         8,913
  Selling and marketing......          --           333           840         2,095         6,831
  Depreciation and
    amortization.............          45           189           265         1,089       386,351
  Option and warrant
    expense..................          --            40            33        19,198        33,524
                               ----------   -----------   -----------   -----------   -----------
    Total operating
      expenses...............         601         2,801         5,178        30,887       441,100
                               ----------   -----------   -----------   -----------   -----------
Operating loss...............        (253)       (2,308)       (4,767)      (28,037)     (432,535)
Interest income, net.........           8             7            70           (60)          108
Equity in losses of
  investments................        (172)         (144)           --        (2,425)       (2,425)
Realized gain (loss) on sale
  of investments.............          --          (302)            4          (169)         (169)
                               ----------   -----------   -----------   -----------   -----------
Net loss.....................  $     (417)  $    (2,747)  $    (4,693)  $   (30,691)  $  (435,021)
                               ==========   ===========   ===========   ===========   ===========
  Pro forma net loss per
    share-basic and
    diluted..................  $    (0.04)  $     (0.22)  $     (0.29)  $     (1.45)  $    (16.90)
                               ==========   ===========   ===========   ===========   ===========
  Pro forma weighted average
    shares used in computing
    net loss per share-basic
    and diluted..............  10,554,795    12,655,901    15,916,383    21,207,225    25,744,511
                               ==========   ===========   ===========   ===========   ===========

<CAPTION>
                                    YEAR ENDED DECEMBER 31,
                               ----------------------------------
                                       1999 PRO FORMA
                               ----------------------------------
                                                  ACQUISITIONS,
                                                  COMMON STOCK
                                ACQUISITIONS           AND
                                 AND COMMON     CONVERTIBLE NOTES
                               STOCK OFFERING       OFFERINGS
                               --------------   -----------------
<S>                            <C>              <C>
CONSOLIDATED STATEMENT OF
  OPERATIONS DATA:
Revenue:
  Subscriber revenue.........   $    11,200        $    11,200
  Engineering services
    revenue..................         2,594              2,594
  Software and related
    services revenue.........         2,317              2,317
                                -----------        -----------
      Total revenue..........        16,111             16,111
  Cost of subscriber
    revenue..................         4,639              4,639
  Cost of engineering
    services revenue.........         1,366              1,366
  Cost of software and
    related services
    revenue..................         1,541              1,541
                                -----------        -----------
      Total cost of
         revenue.............         7,546              7,546
                                -----------        -----------
      Gross profit...........         8,565              8,565
Operating expenses:
  Research and development...         5,481              5,481
  General and
    administrative...........         8,913              8,913
  Selling and marketing......         6,831              6,831
  Depreciation and
    amortization.............       386,351            386,351
  Option and warrant
    expense..................        33,524             33,524
                                -----------        -----------
    Total operating
      expenses...............       441,100            441,100
                                -----------        -----------
Operating loss...............      (432,535)          (432,535)
Interest income, net.........           108            (14,332)
Equity in losses of
  investments................        (2,425)            (2,425)
Realized gain (loss) on sale
  of investments.............          (169)              (169)
                                -----------        -----------
Net loss.....................   $  (435,021)       $  (449,461)
                                ===========        ===========
  Pro forma net loss per
    share-basic and
    diluted..................   $    (15.41)       $    (15.92)
                                ===========        ===========
  Pro forma weighted average
    shares used in computing
    net loss per share-basic
    and diluted..............    28,735,730         28,235,730
                                ===========        ===========
</TABLE>
<TABLE>
<CAPTION>

                             1996        1997         1998         1999
                          ----------   ---------   ----------   ----------
<S>                       <C>          <C>         <C>          <C>
CONSOLIDATED BALANCE
  SHEET DATA:
  Cash and cash
    equivalents.........  $       51   $     132   $    1,755   $   78,542
  Working capital
    (deficit)...........         181        (323)       7,519       83,128
  Total assets..........       1,269         822        8,765      102,534
  Total debt............          --         150           --           --
  Members' capital......       1,101          74        8,030           --
  Stockholders'
    equity..............          --          --           --       98,342

<CAPTION>
                                       AS OF DECEMBER 31, 1999 PRO FORMA
                          ------------------------------------------------------------
                                                                 ACQUISITIONS, COMMON
                                           ACQUISITIONS AND      STOCK AND CONVERTIBLE
                          ACQUISITIONS   COMMON STOCK OFFERING      NOTES OFFERINGS
                          ------------   ---------------------   ---------------------
<S>                       <C>            <C>                     <C>
CONSOLIDATED BALANCE
  SHEET DATA:
  Cash and cash
    equivalents.........   $   47,719         $  354,288              $  547,088
  Working capital
    (deficit)...........       37,064            362,608                 555,408
  Total assets..........    1,244,067          1,667,637               1,877,637
  Total debt............       19,337                362                 200,362
  Members' capital......           --                 --                      --
  Stockholders'
    equity..............    1,219,145          1,671,690               1,671,690
</TABLE>

                                       26
<PAGE>   29

                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS

     You should read the following description of our financial condition and
results of operations in conjunction with the financial statements and the notes
thereto and the unaudited pro forma condensed consolidated financial information
included in this prospectus beginning on page F-1.

OVERVIEW

     Aether Systems, Inc. was originally formed as Aeros, L.L.C. in January
1996. We changed our name to Aether Technologies International, L.L.C. effective
August 1996 and to Aether Systems LLC effective September 1999. Immediately
before completing our initial public offering of common stock on October 26,
1999, the limited liability company was converted into a corporation called
Aether Systems, Inc.

     Development of our business.  From our inception until March 1997, we
primarily provided wireless engineering services, including the development of
wireless software applications for customers. In March 1997, we began offering
services that provide the users of wireless handheld devices access to real-time
financial information. During 1997, we made a strategic decision to focus a
significant portion of our engineering resources on the development of these and
other wireless data services and systems, including our AIM package of wireless
messaging software and software development tools (also known as a software
platform). This resulted in a decrease in engineering services revenue as a
percentage of total revenue and an increase in subscriber revenue as a
percentage of total revenue. We expect this trend to continue in the foreseeable
future. We also expect to derive revenue from licensing our software.

     In August 1999, we formed a new company with 3Com called OpenSky, which was
renamed OmniSky in October 1999. We formed OmniSky with 3Com to pursue
opportunities in the emerging consumer and business mass markets for wireless
e-mail, Internet access and other electronic transactions applications. As of
February 15, 2000, we owned 33% of OmniSky. OmniSky is obligated to pay us $1.50
per month per subscriber for use of our network operations center. We have the
right to offer OmniSky's services to our subscribers in exchange for a monthly
fee to OmniSky of $3 per subscriber. On November 15, 1999, OmniSky launched its
service in a limited test phase of 5,000 subscribers and in January 2000
expanded the program to up to 7,000 subscribers. As of February 16, 2000,
OmniSky had enrolled approximately 6,800 subscribers. We provide engineering
services to OmniSky under a $3 million agreement that extends through June 2000.

     On September 28, 1999, we acquired Mobeo, which provides employees and
customers of major banks and financial institutions with real-time price quotes
and news for foreign exchange, government securities and commodities markets on
wireless handheld devices.

     On February 3, 2000, we acquired LocusOne, which provides wireless data
systems to companies that distribute goods and services using their own delivery
fleets.

     On February 7, 2000, we agreed to invest $10 million to acquire a 27.5%
interest in Inciscent, a new company we formed with Metrocall, PSINet, Hicks,
Muse, Tate & Furst and other investors through which we plan to develop wireless
e-mail, Internet access and other applications for the small office and home
office market segments. As part of the investment, we also agreed to acquire
approximately 9.9% of the outstanding capital stock of Metrocall for
approximately $17 million. Under the agreement, we will grant a perpetual AIM
license to Inciscent for $1 million and perform engineering services under a $4
million contract.

     On February 8, 2000, we signed a letter of intent with Reuters to establish
a European wireless venture, which will be headquartered in the United Kingdom
and initially focused on financial markets. The letter of intent provides that
we will acquire a 60% interest in the new company for $100 million. Our letter
of intent with Reuters does not commit either us or Reuters to form the new
company and remains subject to definitive documentation and the receipt of
proceeds from this offering to fund the investment.

                                       27
<PAGE>   30

     On February 9, 2000, we entered into an agreement to acquire Riverbed,
which develops software that extends the accessibility of applications and
information from corporate networks and databases to handheld devices.

     Our subscriber and revenue information.  Our subscriber base has
historically been derived from financial data and online trading services. The
following table shows the number of subscribers to our financial data services
and online trading services as of December 31 of each of the years shown.

<TABLE>
<CAPTION>
                                                              1997   1998   1999
                                                              ----   ----   -----
<S>                                                           <C>    <C>    <C>
Financial data services.....................................  150    687    4,288
Online trading services.....................................   --     --      277
                                                              ---    ---    -----
          Total subscribers.................................  150    687    4,565
</TABLE>

     The growth in subscribers over these periods was primarily the result of
the attraction of new subscribers to our services, the introduction of new
services and, in 1999, subscribers added through our acquisition of Mobeo. In
1997 our subscriber base was comprised of users of our AirBroker service.
Reuters MarketClip was introduced in March 1998 and produced the majority of our
subscriber growth in 1998. MarketClip provides real-time wireless access to
financial data. Reuters MarketClip yearly subscriptions started to expire in
March 1999 and 77.2% of all subscribers eligible to renew during the period from
March to December 1999 renewed their contracts for an additional one-year
period. In October 1999, we introduced Morgan Stanley Dean Witter Online
TradeRunner. TradeRunner provides real-time wireless financial data and enables
subscribers to trade stocks and options using wireless handheld devices. The
introduction of online trading service subscribers was due to the launch of
TradeRunner in October 1999.

     The majority of the growth in financial data services subscribers in 1999
is attributable to the acquisition of Mobeo, which had 3,294 subscribers as of
December 31, 1999. Mobeo's subscriber base is primarily attributable to its
foreign exchange products. Mobeo had 3,339 subscribers as of December 31, 1998
and 2,811 subscribers as of December 31, 1997. The net increase in Mobeo's
subscriber base from the end of 1997 to the end of 1998 was due to new
subscriptions of 1,660 and terminations of 1,132 subscriptions. The net decrease
in subscribers from December 31, 1998 to December 31, 1999 was due to the
termination of 1,186 subscriptions and the addition of 1,124 new subscriptions.
We believe that a substantial number of Mobeo subscriber terminations and
additions is the result of changes in personnel at financial institutions whose
traders are Mobeo subscribers. We believe the decrease in new subscribers
between 1998 and 1999 was caused by a consolidation among financial institutions
and the transition associated with the sale of Mobeo and its integration into
our operations. We plan to increase sales and marketing efforts with respect to
our foreign exchange services and to bundle the services with additional
applications. We expect that growth from online trading services will exceed
growth from financial data services as we introduce new services.

     For the year ended December 31, 1999, our cost to acquire subscribers was
greater than the revenue we derived from those subscribers over the initial
one-year contract term. The cost to acquire subscribers during this period was
approximately $2.2 million and the contracts entered into during that period
provide for payments of approximately $499,000 during the one-year term of the
contracts. We expect that revenue from new customers will begin to exceed
subscriber acquisition costs when the number of subscribers increases to cover
our fixed costs. This will depend on the rate at which subscriber levels
increase, and we cannot determine when this will occur or assure you that it
will ever occur.

     We expect to derive revenue from the licensing of our AIM software platform
and the ScoutWare software suite that we will acquire upon completing our
acquisition of Riverbed. We also expect to derive licensing revenue associated
with our e-Mobile Delivery transportation logistics and delivery services. To
date, we have not received any revenue from licensing our AIM software platform.

     LocusOne's revenue primarily consists of service revenue relating to
systems integration and ongoing support, software licensing and equipment sales.
LocusOne also receives recurring revenue for use of its network operations
center, which is expected to become a higher percentage of total revenue in the
future.

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LocusOne's customers include Physician Sales & Service, Inc., MAC Papers, Inc.,
Office Depot, Inc., NuCo2, Inc. and Suntory Water Group. These customers
accounted for a substantial majority of LocusOne's revenue in 1999.

     Riverbed's revenue primarily consists of fees generated from licensing
software and providing related services, including maintenance and technical
support, training and consulting. A substantial majority of Riverbed's 1999
revenue was received from 3Com, Extensity, Inc., Aether, Oracle and OmniSky.

     Operating losses.  Since our inception, we have invested significant
capital to build our customer service and network operations center.
Additionally, we have incurred significant operating costs to develop our AIM
software platform and other software applications and to grow our business. As a
result, we have incurred operating losses since our inception. Part of our
strategy is to continue to invest in business development, research and
development and marketing and advertising. In addition, our acquisitions of
Mobeo and LocusOne and our pending acquisition of Riverbed will result in option
and warrant expense and very significant amortization of intangible assets. As a
result, we expect to continue to incur operating losses for the foreseeable
future.

RESULTS OF OPERATIONS

     We currently derive our revenue primarily from the sale of wireless data
services and by providing wireless engineering services. Revenue from wireless
data services generally consists of:

     - a one-time, non-refundable per-subscriber activation fee, which we
       recognize upon service activation;

     - monthly per-subscriber service fees, which we recognize as services are
       provided; and

     - monthly per-subscriber exchange fees for access to financial information
       from the securities exchanges and markets, which we recognize as services
       are provided. We pay a corresponding fee to the various exchanges and
       markets on a regular basis.

We also derive revenue from providing our subscribers with the option to
purchase wireless handheld devices from us at cost, which we bill over the
initial term of the contract. Contracts with our wireless data subscribers are
generally for a one-year period and include a termination penalty if cancelled
by the subscriber before the one-year term expires. These contracts are
generally renewable at the option of the subscriber for additional one-year
periods or otherwise continue on a monthly basis until cancelled by the
subscriber. Revenue from wireless engineering services consists of amounts
billed to our customers for engineering time on an hourly basis or on a fixed
per project basis. This revenue is recognized as the work is performed. With the
acquisition of LocusOne and the pending acquisition of Riverbed, we expect to
derive revenue from software licensing, including licensing fees, maintenance
fees and support fees.

     Cost of subscriber revenue consists primarily of airtime costs, financial
data costs, wireless handheld device costs and securities exchange and market
fees. Our airtime costs are determined by agreements we have with several
wireless carriers. Typically, we have one-year contracts to buy data network
capacity either for an agreed amount of kilobytes at a flat fee or on a
cents-per-kilobyte basis. Cost of engineering services revenue consists of cash
compensation and related costs for engineers, subcontractors and other
non-reimbursed, project-related costs. With the acquisition of LocusOne and the
pending acquisition of Riverbed, we expect to incur costs relative to software
licensing, including royalty payments and personnel costs.

     Research and development expenses consist primarily of cash compensation
and related costs for engineers engaged in research and development activities
and, to a lesser extent, costs of materials relating to these activities. We
expense research and development costs as we incur them. General and
administrative expenses consist primarily of cash compensation and related costs
for general corporate and business development personnel, along with rent and
other costs. Selling and marketing expenses consist primarily of advertising and
promotions, sales and marketing personnel, travel and entertainment and other
costs.
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     Depreciation and amortization expenses consist primarily of amortization of
intangible assets acquired in the Mobeo acquisition and depreciation expenses
arising from equipment purchased for our network operations center and other
property and equipment purchases. With the acquisition of LocusOne and the
pending acquisition of Riverbed, depreciation and amortization expenses will
consist primarily of amortization related to goodwill and other intangibles to
be recognized as a result of these acquisitions.

     Option and warrant expense consists of expenses recorded to account for the
difference, on the date of grant, between the fair market value and the exercise
price of options issued to employees and the fair value of equity-based awards
to non-employees. With the acquisition of Mobeo and LocusOne and the pending
acquisition of Riverbed, we expect to have substantial additional option and
warrant expense.

     Other income (expense) consists of interest income, interest expense,
equity in losses of our investment in OmniSky, and realized losses on our
investments.

FISCAL YEARS ENDED DECEMBER 31, 1997, 1998 AND 1999

     Subscriber revenue. Subscriber revenue of $161,400 for the year ended
December 31, 1997 is attributable to our AirBroker service, which provides
real-time financial information via cellular phones. Subscriber revenue
increased to $549,057 for the year ended December 31, 1998 primarily due to the
launch of Reuters MarketClip in March 1998. Subscriber revenue increased to $3.7
million for the year ended December 31, 1999 as a result of an increase in
MarketClip subscribers, the introduction of TradeRunner and the acquisition of
Mobeo in September 1999. Services acquired from Mobeo contributed revenue of
$2.4 million for the year ended December 31, 1999.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, subscriber revenue for the
year ended December 31, 1999 was $11.2 million. Mobeo accounted for 88.2% of
this subscriber revenue. Subscriber revenue for Mobeo increased from $7.1
million for the year ended December 31, 1997 to $8.6 million for the year ended
December 31, 1998 and to $9.9 million for the year ended December 31, 1999. The
increases from 1997 to 1998 and from 1998 to 1999 were primarily due to price
increases for Mobeo's foreign exchange information services.

     Engineering services revenue. Engineering services revenue decreased from
$1.6 million for the year ended December 31, 1997 to $1.0 million for the year
ended December 31, 1998 and increased to $2.6 million for the year ended
December 31, 1999. The decrease in engineering services revenue from 1997 to
1998 was primarily due to our decision to focus our efforts on developing our
AIM software platform and wireless data services. One of our investors accounted
for approximately 37% of engineering services revenue for 1997. The increase
from 1998 to 1999 was primarily due to the contract with OmniSky described in
the section entitled, "-- Overview." We recognized $2.2 million under this
contract for the year ended December 31, 1999.

     The acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed did not have a material effect on engineering services revenue on a pro
forma basis for the year ended December 31, 1999.

     Software and related services revenue. We did not earn any software and
related services revenue in 1997, 1998 and 1999. On a pro forma basis, giving
effect to the acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed, software and related services revenue was $2.3 million in 1999,
primarily as a result of licenses sold by Riverbed on its ScoutWare software
platform and systems integration and support services provided by LocusOne.

     Cost of subscriber revenue. Cost of subscriber revenue increased from
$447,480 for the year ended December 31, 1997 to $797,165 for the year ended
December 31, 1998 and to $2.1 million for the year ended December 31, 1999. We
began to incur costs of subscriber revenue in 1997 with the March 1997 launch of
our AirBroker service. The increase in the cost of subscriber revenue from 1997
to 1998 was primarily due to the launch of the Reuters MarketClip service in
March 1998. The increase from 1998 to 1999 was a result of an increase in
MarketClip subscribers, the introduction of TradeRunner and the acquisition of
Mobeo in September 1999. Cost of subscriber revenue from services acquired from
Mobeo
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<PAGE>   33

totaled $859,223 in 1999. We expect the number of subscribers for financial
services and online trading services to increase resulting in an increase in the
cost of subscriber revenue. Mobeo has entered into a new airtime supply
agreement with a paging company. In the first quarter of 2000, Mobeo will
provide a new pager to each of its subscribers at no cost as the existing pagers
are not compatible with the new supplier's network. As a result, we expect to
record approximately $500,000 of expense in the first quarter of 2000 relating
to supplying these pagers.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, cost of subscriber revenue for
the year ended December 31, 1999 was $4.6 million. Mobeo accounted for 73.0% of
these costs. Cost of subscriber revenue for Mobeo decreased from $3.1 million
for the year ended December 31, 1997 to $3.0 million for the year ended December
31, 1998 and increased to $3.4 million for the year ended December 31, 1999. The
decrease from 1997 to 1998 was primarily due to cost savings related to a change
in financial data providers and the increase from 1998 to 1999 was primarily due
to an increase in subscriber revenue. As a percentage of subscriber revenue,
cost of subscriber revenue decreased from 35.4% in 1998 to 34.3% in 1999.

     Cost of engineering services revenue. Cost of engineering services revenue
decreased from $846,140 for the year ended December 31, 1997 to $304,137 for the
year ended December 31, 1998 and increased to $1.4 million for the year ended
December 31, 1999. The decrease from 1997 to 1998 was primarily due to our
decision to focus our efforts on developing our AIM software platform and
wireless data services. The increase from 1998 to 1999 was primarily due to the
contract with OmniSky described in the section entitled, "-- Overview."

     The acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed did not have a material effect on cost of engineering services revenue
on a pro forma basis for the year ended December 31, 1999.

     Cost of software and related services revenue. We had no costs associated
with software and related services revenue in 1997, 1998 and 1999. However, we
did incur research and development expenses as discussed below. On a pro forma
basis, giving effect to the acquisitions of Mobeo and LocusOne and the pending
acquisition of Riverbed, cost of software and related services revenue was $1.5
million in 1999 and included royalty fees and personnel costs of Riverbed and
LocusOne.

     Research and development expenses. Research and development expenses
increased from $733,630 for the year ended December 31, 1997 to $1.3 million for
the year ended December 31, 1998 and to $2.6 million for the year ended December
31, 1999. These increases in research and development expenses were primarily
due to the hiring of additional engineers for increased research and development
activities associated with the development of our AIM software platform and
wireless data services.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, research and development
expenses for the year ended December 31, 1999 were $5.5 million. Riverbed
accounted for 37.4% of the expenses, Mobeo accounted for 22.1% of the expenses
and LocusOne accounted for 1.0% of the expenses. Research and development
expenses for Mobeo increased from $174,867 for the year ended December 31, 1997
to $496,570 for the year ended December 31, 1998 and to $1.2 million for the
year ended December 31, 1999. The increase from 1997 to 1998 was primarily due
to an increase in the number of engineering personnel, and the increase from
1998 to 1999 was primarily due to additional expenses associated with the
development of wireless software applications.

     General and administrative expenses. General and administrative expenses
increased from $1.5 million for the year ended December 31, 1997 to $2.8 million
for the year ended December 31, 1998 and to $5.9 million for the year ended
December 31, 1999. These increases were primarily due to the addition of
personnel performing general corporate and business development functions.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, general and administrative
expenses for the year ended December 31, 1999 were $8.9 million. Mobeo accounted
for 16.6% of these expenses, Riverbed accounted for 11.8% of these
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<PAGE>   34

expenses and LocusOne accounted for 9.3% of these expenses. General and
administrative expenses for Mobeo increased from $1.9 million for the year ended
December 31, 1997 to $2.7 million for the year ended December 31, 1998 and to
$2.3 million for the year ended December 31, 1999 before pro forma adjustment.
The increase from 1997 to 1998 was primarily due to personnel and related costs.
The decrease from 1998 to 1999 is primarily attributable to decreased
compensation and professional fee expense as a result of our acquisition of
Mobeo.

     Selling and marketing expenses. Selling and marketing expenses increased
from $333,191 for the year ended December 31, 1997 to $840,455 for the year
ended December 31, 1998 and to $2.1 million for the year ended December 31,
1999. Of the increase from 1997 to 1998, $324,152 was due to an increase in
advertising and promotion costs related to the launch of Reuters MarketClip in
March 1998, and the remaining amount relates to an increase in personnel and
costs associated with sales and marketing. From 1998 to 1999, the increase
relates primarily to increases in the number of sales and marketing personnel.
This expense is expected to increase significantly in 2000 as a result of
increased spending in advertising.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, selling and marketing expenses
for the year ended December 31, 1999 were $6.8 million. Mobeo accounted for
26.6% of these expenses, Riverbed accounted for 41.9% of these expenses and
LocusOne accounted for 7.9% of these expenses. Selling and marketing expenses
for Mobeo increased from $1.8 million for the year ended December 31, 1997 to
$2.3 million for the year ended December 31, 1998 and to $2.6 million for the
year ended December 31, 1999 before pro forma adjustment. The increases from
1997 to 1998 and from 1998 to 1999 were primarily due to increased personnel
overhead costs.

     Depreciation and amortization expenses. Depreciation and amortization
expenses increased from $189,160 for the year ended December 31, 1997 to
$264,685 for the year ended December 31, 1998 and to $1.1 million for the year
ended December 31, 1999. The increase from 1998 to 1999 was primarily due to
amortization of goodwill and other intangibles related to the Mobeo acquisition
and additional capital expenditures.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, depreciation and amortization
expenses for the year ended December 31, 1999 were $386.4 million. This amount
primarily reflects amortization related to goodwill and other intangibles to be
recognized as a result of the acquisitions of Mobeo and LocusOne and the pending
acquisition of Riverbed.

     Option and warrant expense. Option and warrant expense decreased from
$40,277 for the year ended December 31, 1997 to $32,580 for the year ended
December 31, 1998 and increased to $19.2 million for the year ended December 31,
1999. The changes in option and warrant expense for 1998 and 1999 reflect
changes in the extent to which options with exercise prices less than the fair
value on the date of grant were granted during the period. Approximately $16.5
million of the expense in 1999 relates to warrants granted to the chief
executive officer and other key executives which became fully vested as a result
of our initial public offering.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, option and warrant expense for
the year ended December 31, 1999 was $33.5 million. The increase from Aether's
historical amount is primarily due to expenses associated with options granted
to employees of LocusOne and to the selling stockholders of Mobeo for consulting
and employee services.

     Interest income, net. Net interest income increased from $7,788 for the
year ended December 31, 1997 to $70,308 for the year ended December 31, 1998 and
decreased to net interest expense of $60,282 for the year ended December 31,
1999. The increase from 1997 to 1998 was primarily due to increased cash
balances as a result of our private placement financings completed in August
1998 and October 1998. The decrease to a net expense from 1998 to 1999 relates
to interest and related expense of a loan that

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<PAGE>   35

funded the purchase price of Mobeo, partially offset by interest earned on the
proceeds from our initial public offering. The loan was repaid at the time of
our initial public offering.

     Equity in losses of investments. Our equity in the loss of Real World
Solutions, a joint venture, and Navox, Inc., was $144,825 for the year ended
December 31, 1997. This amount related to losses of Real World Solutions and
Navox recorded by us under the equity method of accounting. The $2.4 million of
equity in losses of investments in 1999 relates to our proportionate share of
losses in OmniSky under the equity method of accounting.

     Realized loss on sale of investment. In the year ended December 31, 1997,
we sold our interest in Real World Solutions and recorded a loss of $302,145. In
the year ended December 31, 1999, we recorded a loss of approximately $169,000
resulting from the sale of short-term investments.

LIQUIDITY AND CAPITAL RESOURCES

     Since our inception, we financed our operations primarily through private
placements of our equity securities and our initial public offering, which in
the aggregate resulted in net proceeds of $116.8 million through December 31,
1999. As of December 31, 1999, we had $80.7 million in cash and short-term
investments and $83.1 million of working capital.

     Net cash used in operating activities was $1.5 million for the year ended
December 31, 1997, $4.4 million for the year ended December 31, 1998 and $12.1
million for the year ended December 31, 1999. The principal use of cash in each
of these periods was to fund our losses from operations. In October 1999, the
Company agreed to pay for the purchase of 25,000 Minstrel V modems from OmniSky
for a price per modem of $230. OmniSky has an exclusive buying arrangement with
Novatel for Minstrel V modems, which began in December and runs through March
2000. As of December 31, 1999 we have paid for 20,000 of the 25,000 modems for a
total purchase price of $4.6 million. The modems are being delivered to us
through April 2000.

     Net cash used in investing activities was $209,723, for the year ended
December 31, 1997, $6.5 million for the year ended December 31, 1998 and $12.6
million for the year ended December 31, 1999. Cash used in investing activities
for the year ended December 31, 1997 was primarily for the purchase of property
and equipment offset in part by proceeds from the sale of our joint venture
interest in Real World Solutions. Cash used in investing activities for the year
ended December 31, 1998 was primarily for the purchase of short-term
investments. For the year ended December 31, 1999, we invested $3.9 million in
short-term investments, $11.5 million to acquire Mobeo, $2.5 million to increase
our investment in OmniSky to 33% and $2.4 million in property and equipment.

     Net cash provided by financing activities was $1.8 million for the year
ended December 31, 1997, $12.5 million for the year ended December 31, 1998 and
$101.4 million for the year ended December 31, 1999. Cash provided by financing
activities in 1997 and 1998 was primarily attributable to proceeds from private
sales of our equity securities and cash provided by financing activities in 1999
consisting primarily of proceeds from our initial public offering. On September
28, 1999, we borrowed $14.8 million under a senior secured interim credit
facility with Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith
Incorporated, one of the underwriters of our initial public offering, and
Merrill Lynch Capital Corporation for the primary purpose of funding the
acquisition of Mobeo. On October 26, 1999, we completed our initial public
offering and raised net proceeds (after expenses of the offering) of
approximately $101.1 million. A portion of the proceeds of the initial public
offering was used to pay off the $14.8 million loan.

     On January 18, 2000, OmniSky sold equity capital through a private
placement and as a result we invested $6.7 million to retain our 33% interest in
OmniSky.

     On February 3, 2000, we acquired the capital stock of LocusOne for a
purchase price of $40 million, including $21 million in cash at the time of
closing. The remaining $19 million is in the form of two notes payable as
discussed below.

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     For 2000, we expect to have the following additional expenditures and
requirements:

     - On February 7, 2000, we agreed to acquire a 27.5% interest in Inciscent
       for $10 million, a new company we formed with Metrocall, PSINet, Hicks,
       Muse, Tate & Furst and other investors through which we plan to develop
       wireless e-mail, Internet access and other applications for the small
       office and home office market segments. As part of the investment, we
       also agreed to acquire approximately 9.9% of the outstanding capital
       stock of Metrocall for approximately $17 million.

     - On February 8, 2000, we signed a letter of intent with Reuters to
       establish a European wireless company headquartered in the United
       Kingdom, which will be initially focused on financial markets. The letter
       of intent provides that we will acquire a 60% interest in the company for
       $100 million. The formation of this company remains subject to definitive
       documentation and our receiving money to fund the investment.

     - As part of our LocusOne acquisition, we issued two notes that are due in
       2000. One note totaling $5.4 million is payable at the time of the
       closing of this offering. The remaining $13.6 million note is payable at
       December 31, 2000 and will be repaid with proceeds of this offering to be
       placed in escrow.

     - We estimate we will pay $25 million to enhance our sales and marketing
       activities, $12 million of which we have already committed to spend for a
       nationwide broadcast and print branding and advertising campaign.

     - Other potential acquisitions, investments and agreements we may identify.

     We currently anticipate that our available cash resources combined with the
net proceeds from this offering and the concurrent offering of convertible notes
will be sufficient to fund our operating needs for at least the next 12 months,
including the expansion of our sales and marketing program. We expect that our
available cash resources combined with the net proceeds from these offerings
will also support our current acquisition strategy during this period.

YEAR 2000 IMPACT

     Many currently-installed computer systems and software products are coded
to accept or recognize only two digits rather than four digits to define the
year in the date code field. These systems and software products need to accept
four digit year entries to distinguish 21st century dates from 20th century
dates. Systems and products that are not corrected to do this could cause a
disruption of operations including a temporary inability to process
transactions, send invoices or engage in other normal business activities. We
maintain a significant number of computer software systems and operating systems
across our entire organization, which are potentially subject to year 2000
problems. Although January 1, 2000 has passed without any disruption of
operations, problems related to the year 2000 could still surface.

     The discussion below includes the products and infrastructure of Aether and
its recent acquisition, Mobeo, except where noted.

     We took several steps to prepare for the year 2000 transition. We developed
all our in-house software, including our AIM software platform, using four digit
date codes. We run all these applications on hardware and operating systems that
we have determined are year 2000 compliant. The Reuters MarketClip and Morgan
Stanley Dean Witter Online TradeRunner applications have operated successfully
in the year 2000. All our computer hardware has been inventoried and checked
against the manufacturers' year 2000 compliance declarations. All non-compliant
hardware was upgraded, or replaced. All third-party software, including
operating systems and applications, has been inventoried and checked against the
manufacturers' compliance statements. We upgraded and fixed software as
recommended by the manufacturers.

     We received assurances from external entities that could affect our
business. We have on file the compliance statements of our data providers,
landline and wireless network carriers, device manufacturers and current
corporate customers whose systems might impact our own systems.
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     We have reviewed potential failures that may yet arise as a result of the
year 2000 transition. With the assistance of an outside consultant, we conducted
a business impact analysis and mapped the most critical of these failures into a
contingency plan that identified proactive measures to be taken to prepare for
system failures as well as those people responsible. In the event of a material
system or product failure in spite of our efforts to date, a crisis management
plan has been developed and is in place if needed.

     The most likely worst case scenario would be the failure of the landline or
wireless networks that carry data to us or from us to our customers. If this
happened, we would not be able to deliver our services to our customers and we
may lose revenue.

     Although we have taken the steps described above to make our systems year
2000 compliant and have experienced no year 2000 disruptions to date, we may
experience material problems and expenses associated with year 2000 compliance
that could adversely affect our business, results of operations and financial
condition. If the assurances we or our acquired companies have received from
third parties regarding their compliance is inaccurate we may experience
disruption resulting in additional expense and loss of revenue. We are also
subject to outside forces that might generally affect industry and commerce,
such as year 2000 compliance failures by utility or transportation companies. If
our customers experience disruptions related to our services and software
systems, they may begin litigation against us even if the disruptions were
caused by their own systems or software provided by others.

     We have purchased most of our equipment within the last four years, which
has kept the costs of year 2000 compliance efforts to a minimum. All
non-compliant software and equipment has been upgraded or replaced at a cost
that is not material to us and our total costs relating to year 2000 compliance
have been less than $100,000. Based on our review of compliance to date, we do
not expect any future costs related to year 2000 compliance to be material.

     Riverbed was established in October 1998 and thus substantially all of its
network systems, personal computers, laptop computers and handheld computers
were purchased during 1999. Equipment and applications were purchased only from
vendors with favorable year 2000 compliance statements. Riverbed software
applications were tested for year 2000 compliance and defects were repaired. No
disruption of operations occurred during the transition to January 1, 2000.

     LocusOne validated its hardware and software systems against vendor
compliance statements. One server was determined to be non-compliant and was
replaced. The software of one of LocusOne's wireless network carriers had
several year 2000 formatting problems that LocusOne accommodated in its software
and procedures. These formatting problems do not affect the operation of the
wireless service. LocusOne tested its software and systems for year 2000
compliance and all systems and services functioned properly. No disruption of
operations occurred during the transition to January 1, 2000.

NEW ACCOUNTING PRONOUNCEMENTS

     In June 1998, the FASB issued SFAS No. 133, "Accounting for Derivative
Instruments and Hedging Activities." The new standard establishes accounting and
reporting standards for derivative instruments, including certain derivative
instruments embedded in other contracts and for hedging activities. This
statement, as amended, is effective for all fiscal quarters beginning after June
15, 2000. We do not expect SFAS No. 133 to have a material effect on its
financial position or results of operations.

QUALITATIVE AND QUANTITATIVE DISCLOSURE REGARDING MARKET RISK

     We have limited exposure to financial market risks, including changes in
interest rates. We manage our interest rate risk exposure by investing in debt
obligations with varying maturity dates. At December 31, 1999, we had short-term
investments of approximately $2.1 million. These short-term investments
consisted of highly liquid investments in debt obligations of the U.S.
Government and other highly-rated entities with maturities of up to 30 years.
These investments are classified as available-for-sale and are considered
short-term, because we expect to sell them within 12 months. These investments
are subject to interest rate risk and will fall in value if market interest
rates increase. At December 31, 1999,

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<PAGE>   38

the value of our short-term investments was approximately $70,069 less than our
cost. If market interest rates continue to rise, the value of our short-term
investments will continue to decrease. We expect to sell these investments prior
to maturity, and therefore we may not realize the full value of these
investments. We currently hold no derivative instruments and do not earn
foreign-source income. We expect to invest only in short-term, investment grade,
interest-bearing instruments.

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                                    BUSINESS

OVERVIEW

     We provide wireless data services, systems and software enabling people to
use handheld devices for mobile data communications and real-time transactions.
We design, develop, sell and support complete wireless systems for corporations
seeking to make data available to mobile workers or consumers. Our capabilities
include our wireless data engineering and development expertise, our wireless
integration software, our customer service and network operations center and,
following our acquisition of Riverbed, our mobile data management software.

MARKET OPPORTUNITY

  Growth of the Internet, Intranets and Extranets

     The Internet and businesses' internal data networks, or intranets, have
emerged as global communications channels that allow users to share information
and conduct real-time business electronically. Technology and communications
research firm International Data Corporation, or IDC, estimates there were
approximately 212 million worldwide users of the Internet at the end of 1999 and
that the number of users will increase to 510 million by the end of 2003. IDC
also estimates that by 2001 there will be 133 million global intranet users.
Businesses are also increasingly employing extranets, which allow them to
communicate and conduct transactions electronically with their customers and
suppliers. Forrester Research forecasts that business-to-business Internet
commerce in the United States will increase from an estimated $406 billion in
2000 to $2.7 trillion in 2004. All of the projections and estimates in this
"Market Opportunity" section are based on the qualifications described on page
19 of this prospectus.

  Growth of Mobile Communications

     Individuals are increasingly using mobile devices for convenience and
enhanced productivity when away from their home or office. IDC estimates that in
1998 there were 303 million worldwide cellular and personal communications
systems, or PCS, subscribers, and that number is expected to increase to 1.1
billion in 2003. Use of wireless telecommunications has grown rapidly as
cellular, paging and PCS have become more widely available and affordable for
both the business and mass consumer markets. Advances in technology, regulatory
changes, the introduction of new service providers and price reductions have
contributed to this growth.

  Growth of Wireless Data Applications and Communications

     We believe an increasing number of people will carry wireless devices for
data communications rather than for voice communications alone. The latest
wireless communications devices in the United States, including handheld
personal organizers, notebook computers, pagers and mobile phones, are smaller,
less expensive, have longer battery life and more features than earlier devices.
According to publicly available estimates, the U.S. wireless data market will
grow from 3 million subscribers in 1999 to 36 million subscribers in 2003.
Forrester Research forecasts that 7.1 million European business professionals
and young adults will own Web-enabled smartphones using the Wireless Application
Protocol, or WAP, by the end of 2000 and that there will be 40 million Europeans
using WAP smartphones by the end of 2001.

     The market for wireless data applications is driven by the increased
reliance on the Internet, intranets and extranets and the emergence of a mobile
workforce. IDC forecasts that the remote and mobile workforce in the United
States will grow from 35.7 million individuals at the end of 1999 to 47.1
million at the end of 2003. Having grown accustomed to and dependent on the
information and applications available on their personal computers, we believe
workers and consumers want access to similar information when away from their
office or home.

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  Increased Outsourcing Trends

     As information technology, or IT, systems have become more complex,
companies have increasingly outsourced many of their IT requirements. U.S. firms
are now spending 20% of their IT budgets on outsourcing services, according to
the industry trade publication Internet Week. These include packaged application
software implementation and support, customer support and network development
and maintenance. Companies are choosing to focus on their core businesses and
seeking to reduce costs associated with developing and maintaining IT networks
and software applications. In addition, by outsourcing, companies avoid major
challenges faced in hiring and retaining qualified IT employees and realize
increased time-to-market benefits.

THE AETHER SOLUTION

     Mobile workers and consumers typically gain remote access to electronic
data and transactional capabilities in one of two ways:

     - through continuous, real-time communications between databases and
       handheld devices using wireless communications networks, or

     - by periodically updating, or synchronizing, data between the device and
       database using a direct connection, such as a phone line.

We provide the services and resources necessary to provide these capabilities
using our engineering staff, our wireless integration and mobile data management
software and our customer service and network operations center. Our
capabilities address most of the common issues companies face when building and
supporting wireless and other mobile data systems.

     Issue:  Wireless and other mobile data communications systems are complex.

        Many information technology managers lack the engineering and system
        resources to design, develop, install and maintain new software and
        systems that give their companies' workforces and customers mobile
        access to corporate applications.

     Solution:  We provide comprehensive mobile communications services.

        We have all the resources necessary to design, develop, install and
        maintain wireless and other mobile data communications systems for
        customers. We have 50 engineers, and with the pending acquisition of
        Riverbed we will add 34 engineers. Our engineers use our Aether
        Intelligent Messaging software platform, or AIM, to extend corporate
        applications to almost any wireless environment. Through our pending
        acquisition of Riverbed, we also will provide a complete suite of
        software products that extend corporate data to mobile handheld devices.
        We have established relationships with the leading wireless network
        carriers, including AT&T Wireless Services, Bell Atlantic Mobile,
        BellSouth Wireless Data and GTE Corp. We have negotiated favorable
        airtime agreements with these carriers, allowing us to offer our end
        users flat-rate pricing no matter how much data is transmitted or where
        a device is used. Our network operations center offers a secure gateway
        to wireless networks for data delivered to us by our customers, and our
        customer service center provides devices and call center support to end
        users. We provide as many, or as few, of these elements as customers
        require to develop their systems.

     Issue:  There is a wide variety of incompatible standards.

        To build a wireless data system, a business must integrate disparate
        networks, devices and operating systems. Companies often require
        multiple networks to meet the needs of their workers and customers,
        based on their geographic location and preferred devices, which may use
        different communications protocols. This can involve complex
        negotiations with several wireless carriers. Additionally, companies
        typically use a variety of operating systems for their internal data
        applications.

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     Solution:  Our software and systems can integrate a wide variety of
                networks, devices and operating systems.

        We give our customers a high degree of flexibility and choice, freeing
        them from the need to integrate technologies from a variety of parties
        to develop their systems. Our AIM software platform supports the most
        widely used wireless data networks in the United States, known as CDPD,
        Mobitex and ARDIS, as well as circuit-switched network protocols,
        including GSM and CDMA. As a result, our customers' end users can choose
        the devices they prefer, including Palm, Windows CE and other personal
        organizers, notebook computers, pagers and mobile phones. Our WAP
        Enterprise Center has a team of engineers and sales executives dedicated
        to supporting and developing applications for WAP, a series of
        specifications that allow mobile phones to display Internet information.
        We also are planning to extend our AIM software platform's capabilities
        to the Microsoft micro-browser and the operating system known as EPOC
        for handheld devices developed by Symbian Ltd. (a wireless software
        company jointly owned by Ericsson, Matsushita Communication Industrial
        Co., Ltd., Motorola, Nokia and Psion PLC). Our AIM software platform can
        interact with the major operating systems on which most corporate
        applications run, including Windows NT, UNIX, Linux and most mainframe
        operating systems.

        As connections to new systems have become needed, our engineers have
        adapted our AIM software platform to meet the needs of those systems. We
        believe that as the wireless data market evolves there will continue to
        be a multitude of protocols for networks, devices and operating systems.
        We plan to update our software platforms continually to address the
        ongoing need to integrate these protocols. We believe we are the only
        firm that currently provides this level of service to companies seeking
        to develop wireless data systems.

     Issue:  Wireless data transmissions are slow and expensive.

        Most of today's wireless data networks operate at less than half the
        speed of telephone dial-up connections, limiting the delivery of useful
        data to only small amounts of text and few graphics. Data feeds
        typically include large amounts of unnecessary data, including message
        headers and routing information. Because wireless carriers typically
        charge by the kilobyte of data transmitted, extraneous data add
        unnecessary cost.

     Solution:  Our systems optimize data transmissions for wireless networks.

        Our AIM software platform optimizes data transmission by employing
        compression and data-thinning techniques. As a result, users get
        information faster when they send queries from their devices, and they
        get more useful information for the price. Our AIM software platform
        reduces the number of data packets required in a typical wireless
        transmission by as much as 66%. We ensure reliable message delivery
        through measures that confirm data have arrived properly and resend data
        if no acknowledgement has been received.

        Over the next several years, wireless carriers and equipment vendors are
        planning to build so-called third generation, or 3G, networks, which
        promise to transmit data at much higher speeds and offer more
        compatibility among devices. No matter how fast networks become, the
        need for low cost, secure and reliable data transmission will continue.
        We have designed our AIM software platform to grow with the capabilities
        of wireless networks. For example, we are currently working with U.S.
        and European wireless network carriers to develop our financial trading
        services to operate over networks using General Packet Radio Services,
        known as GPRS, a new high-speed wireless network standard.

     Issue:  Corporate managers require rigorous security standards when
             entrusting their data to third parties.

     Solution:  We provide a secure network operations center.

        Our network operations center has numerous redundant elements and serves
        as a high-security physical link between data feeds from our business
        customers' and others' data systems and
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        wireless carrier networks. This relieves corporations from the burden of
        constructing similar facilities. We believe our network operations
        center is capable of meeting the security standards for services we
        developed or are developing for our customers, who include Reuters,
        Morgan Stanley Dean Witter Online and Charles Schwab. We believe that
        our network operations center is a vital component of our wireless data
        service offerings that differentiates us from our competitors. We
        encrypt, or scramble, digital messages as they move along wireless
        networks using technology licensed from Certicom Corp. Recently we
        reached an agreement to use "digital signature" technology provided by
        Diversinet, which authenticates the identity of the sender and recipient
        of such messages.

     Issue:  Corporate information technology managers are reluctant to
             configure and maintain inventories of wireless devices and provide
             ongoing customer support.

     Solution:  We provide product fulfillment and customer service.

        We send end users fully functioning mobile devices configured for the
        wireless data networks and applications they will use. We also have a
        customer service center providing ongoing end user support. Companies do
        not have to worry about configuring devices for use by their employees
        and customers, fixing broken units, handling warranties or answering
        questions from users.

THE AETHER STRATEGY

     Our strategy is to be the dominant provider of wireless data services and
systems to corporations by using our engineering expertise, our software
platforms, our customer service and network operations center and our other
resources. We seek to maximize recurring revenue by developing wireless data
services. We believe our capabilities and experience have established us as an
early market leader in wireless data services, and a key element of our strategy
is to move quickly into new opportunities to extend our leadership position. Our
strategy includes the following key elements:

     Target a variety of industries and market segments for development of
wireless data communications and services in the United States and
internationally. Our strategy initially focused on developing services for the
financial services sector, whose participants we believe are among the earliest
adopters of wireless data services. While seeking to extend our offerings in the
financial services sector, we also seek to move into other industries and market
segments in the United States and internationally. Since January 2000, we have
entered into the following acquisitions, investments, agreements and letters of
intent in pursuit of this strategy:

     - We agreed to acquire Riverbed, a company that develops and licenses
       mobile data management software. This pending acquisition gives us access
       to the industries Riverbed currently serves, including healthcare,
       transportation logistics and sales force automation.

     - We acquired LocusOne, which develops wireless data systems for companies
       that distribute goods and services using their own delivery fleets. This
       acquisition extends our business to the transportation logistics and
       delivery industry.

     - We entered into a non-binding letter of intent with Reuters to form a new
       company to develop wireless data systems in Europe, initially focusing on
       the financial services industry.

     - We agreed to form a new company, Inciscent, to develop wireless e-mail,
       Internet access and other applications for the small business and home
       office market segments. We agreed to form Inciscent with paging company
       Metrocall, Internet service provider PSINet, investment firm Hicks, Muse,
       Tate & Furst and other investors.

     - We increased our investment in OmniSky, a company we formed with 3Com.
       With our engineering assistance, OmniSky is developing wireless e-mail,
       Internet access and other electronic transactions capabilities primarily
       for the consumer market, and we have the right to offer these
       capabilities to our business customers.

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<PAGE>   43

     - We entered into a non-binding memorandum of understanding with Nextel
       Finance Company to develop wireless data services using the Nextel
       wireless communications network. Nextel and Aether plan to jointly
       develop and market applications for mobile workforces in financial
       services, transportation and other industries. Applications are being
       planned for WAP-enabled Nextel phones as well as for Palm and Windows CE
       devices that are connected to Nextel wireless phones.

     - We entered into a non-binding letter of intent with Proxicom, Inc., an
       Internet consulting and development company, to jointly pursue
       opportunities to provide wireless data services to companies.

     - We entered into a non-binding letter of intent with CyberBills, an online
       bill-paying service, to develop a wireless electronic bill presentment
       and payment service for CyberBills' consumer distribution network.

     Continue to develop the market for existing and new services in the
financial services sector.  We believe that news, stock prices and other
financial information are among the most accessed content on the Internet. The
Internet has also enabled the growth of online trading activity. We have
targeted two types of financial services subscribers, individual investors and
market professionals, each of whom understands the value of receiving real-time
information and trading capabilities. We are currently focused on launching
commercial service for our most recent customers and attracting additional
financial institutions as customers.

     Offer the widest range of software products that address every aspect of
wireless integration and mobile data management for mobile workers and
consumers.  We plan to provide services and products that meet all mobile and
wireless software needs, including our AIM wireless integration software and the
ScoutWare mobile data management software suite, which we will offer following
our acquisition of Riverbed. These offerings give corporate software engineers a
complete set of development tools for designing mobile and wireless data
applications for a wide variety of handheld devices and networks.

     Continue to develop mass-market wireless applications like e-mail and
Internet access and bundle them with custom corporate applications.  Our
involvement with OmniSky, a company we formed in August 1999 with 3Com, allows
us to combine, or "bundle," our custom corporate wireless data services with
wireless e-mail and Internet access offered by OmniSky. We also recently
announced the formation of our WAP Enterprise Center, which provides engineers
who develop applications for wireless phones that offer data services (so called
WAP smartphones) and the systems to support data communications to these
devices. Through our recent investment in Inciscent, a company we formed with
Metrocall, PSINet, Hicks, Muse, Tate & Furst and other investors, we also plan
to develop wireless e-mail, Internet access and other applications for the small
office and home office market segments.

     Expand our customer base and strengthen the Aether brand through enhanced
sales and marketing efforts.  We are increasing our sales and marketing
expenditures significantly to increase our direct sales force and advertise the
Aether brand. We intend to build our sales force focused on companies that want
to provide wireless access to their data applications. Following our acquisition
of Riverbed, we will incorporate its ScoutWare software sales force with our AIM
software platform sales effort. We will target large corporations in industries
that both invest heavily in technology and have significant numbers of mobile
customers or employees. In addition, we will continue to build relationships
with third party software developers who wish to use our software platforms to
provide their applications with wireless capabilities. Our branding efforts will
include advertising, public relations, speaking engagements and sponsorship of
major conferences.

     Maintain and strengthen our strategic relationships with suppliers and
customers.  A key to our ability to provide complete wireless data services to
our customers is our relationships with wireless network carriers and
manufacturers of wireless devices. These relationships take time to develop,
providing us with an advantage by getting our services to market before our
competitors. We intend to maintain and strengthen these relationships by
negotiating more cost-effective rate plans with existing wireless network

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carriers, testing our wireless services with providers of next-generation,
high-speed wireless networks and working with manufacturers and industry forums
to guide development of new devices and applications.

     Apply the expertise we gain through engineering services and research and
development activities to emerging business opportunities.  While we no longer
provide engineering services strictly to generate revenue, we do take on
engineering assignments that might allow us to embrace technological advances or
expand into new industry sectors or services. To this end, we have established a
new research and development division that will evaluate new technologies,
applications and business opportunities that demonstrate significant market
potential. The division will initially be staffed by seven engineers, including
our chief technology officer, who will head that division.

SERVICES AND PRODUCTS

     The services and products we currently offer or are developing or acquiring
include:

     - delivering wireless information and transaction services;

     - software licensing; and

     - providing engineering services for the design, development and support of
       wireless data systems.

     The following table sets forth summary information regarding services and
products we now offer or are developing or acquiring.

WIRELESS INFORMATION AND TRANSACTION SERVICES
- --------------------------------------------------------------------------------

<TABLE>
<CAPTION>
         SERVICE                USERS OF SERVICE      DATE INTRODUCED    REVENUE TYPE             SERVICE DESCRIPTION
- --------------------------  ------------------------  ---------------  -----------------  -----------------------------------
<S>                         <C>                       <C>              <C>                <C>
EXISTING FINANCIAL SERVICES
  Reuters MarketClip        Individual investors      March 1998       Monthly recurring  Market quotes, news and alerts
  TradeRunner               Morgan Stanley Dean       August 1999      Monthly recurring  Equities and options trading,
                            Witter Online investors                                       market quotes, news and alerts
  F/X Alert                 Financial market          September 1999   Monthly recurring  Foreign exchange quotes, news and
                            professionals                                                 alerts

FINANCIAL SERVICES UNDER DEVELOPMENT
  PocketBroker              Charles Schwab online                      Monthly recurring  Equities and options trading,
                            investors                                                     market quotes, news and alerts
  PitViper                  Chicago Board of Trade                     Monthly recurring  Entry and reconciliation of
                            floor traders                                                 commodities orders
  Name to be determined     National Discount                          Monthly recurring  Equities and options trading,
                            Brokers online investors                                      market quotes, news and alerts
  Name to be determined     Brokers or firms                           Monthly recurring  Customer account access and
                            clearing through Bear                                         trading, market quotes, news and
                            Stearns                                                       alerts
  Name to be determined     TD Waterhouse Investor                     Monthly recurring  Equities and options trading,
                            Services online                                               market quotes, news and alerts
                            investors

WIRELESS TRANSPORTATION & DELIVERY SERVICES
  e-Mobile Delivery         Physician Sales &
                            Service                   January 1998     Monthly recurring  LocusOne software suite and
                            MAC Papers                September 1998   and/or licensing   application service that enables
                            Office Depot              June 1999                           wireless transactions at the point
                            NuCo2                     September 1998                      of sale, customer contact or
                            Suntory Water Group       August 1999                         delivery
</TABLE>

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<PAGE>   45

<TABLE>
<CAPTION>
SOFTWARE LICENSING
- ----------------------------------------------------------------------------------------------------------------------------------
PRODUCT                     LICENSEES OF SOFTWARE     DATE OF CONTRACT  REVENUE TYPE       SOFTWARE FUNCTION
- --------------------------  ------------------------  ----------------  -----------------  ---------------------------------------
<S>                         <C>                       <C>               <C>                <C>
  Aether Intelligent        Inciscent*                                  Upfront and/or     Allows for secure, efficient transport
    Messaging                                                           per-user           of data over wireless networks; also
                                                                        licensing fees     provides tools for wireless
                                                                                           applications development
  ScoutWare**               Palm Computing            September 1999    Per-user           Riverbed ScoutWare software suite links
                            U.S. Postal Service       June 1999         licensing fees     mobile devices to corporate data
                            Becton Dickinson          November 1999                        systems, provides application
                            Oracle                    March 1999                           development and management tools
</TABLE>

 * We will license AIM to Inciscent for a one-time charge of $1 million when we
   close our investment in Inciscent. We currently license AIM to Riverbed, whom
   we are acquiring, and have licensed AIM to OmniSky on a royalty-free basis in
   connection with our equity investment in OmniSky.
** We will acquire ScoutWare upon our acquisition of Riverbed.

<TABLE>
<CAPTION>
ENGINEERING SERVICES
- -----------------------------------------------------------------------------------------------------------------------
CUSTOMER                    DATE OF CONTRACT          REVENUE TYPE     SERVICE DESCRIPTION
- --------------------------  ------------------------  ---------------  ------------------------------------------------
<S>                         <C>                       <C>              <C>
  Response Services Center  January 2000              Engineering      Develop location-tracking capabilities for
                                                      fees             towing firms, vehicle fleets
  Merrill Lynch             October 1999              Engineering      Develop wireless financial services for
                                                      fees             financial professionals
  OmniSky                   August 1999               Engineering      Develop and provide e-mail, Internet access and
                                                      fees             electronic transactions capabilities on wireless
                                                                       handheld devices
</TABLE>

  Wireless Information and Transaction Services

     Our wireless information and transaction services and customers are
described below.

     - Reuters MarketClip.  In March 1998, we introduced the Reuters MarketClip
       service, which delivers news stories, real-time financial market price
       quotes, historical graphs and stock alerts from Reuters to Palm and
       Windows CE devices. We charge individual subscribers a flat monthly fee
       for unlimited usage of this service in addition to the fees charged by
       the securities exchanges and markets for the right to view real-time
       price quotes. The service operates using the wireless network systems
       known as CDPD and Mobitex. These networks cover geographic areas that
       enable us to provide service to more than 90% of the U.S. population. We
       also continue to support AirBroker, a predecessor service to Reuters
       MarketClip that provides market information using mobile phones.

     - Morgan Stanley Dean Witter Online TradeRunner.  In August 1999, we
       launched TradeRunner, a service that allows Morgan Stanley Dean Witter
       Online's customers to trade stocks, mutual funds and options using Palm
       devices. In addition, subscribers receive news stories, real-time
       financial market price quotes, historical graphs and stock alerts from
       Reuters. We charge Morgan Stanley Dean Witter Online account holders who
       subscribe to this service a flat monthly fee for unlimited usage, in
       addition to the fees charged by the securities exchanges and markets for
       the right to view real-time price quotes. Users pay Morgan Stanley Dean
       Witter Online's regular commission fees for any trades. We support
       TradeRunner through our customer service and network operations center.
       The service operates using CDPD or Mobitex networks.

     - F/X Alert.  As a result of the Mobeo acquisition, we offer real-time
       information on foreign exchange rates and selected commodities markets.
       These services deliver time-sensitive financial information from Reuters
       over wireless networks that reach the largest 100 metropolitan markets in
       the United States. F/X Alert offers real-time price quotes, news and
       alert tracking for more than 150 financial instruments including foreign
       exchange, fixed income, futures/derivatives and commodities. In addition,
       we continue to offer other Mobeo services, called Scrappy, Energy and
       Pocket Futures, which track the scrap metals, energy and futures markets,
       respectively, as well as

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       Mobeo 1.0, a two-way financial market price quotes and information
       service, similar to MarketClip, that operates using the RIM 950 two-way
       pager.

     - Charles Schwab PocketBroker.  In December 1999, we signed a definitive
       agreement with Charles Schwab to develop a wireless financial trading and
       information service for Schwab's brokerage customers. We are currently
       testing a pilot version of the service. We and our network carriers have
       agreed to pay for advertising and marketing of this service and match the
       amount spent by Schwab up to an agreed upon maximum amount. In addition,
       we have agreed to provide engineering support to implement Schwab's
       service at no charge for two years. At launch, we will charge Schwab
       customers who subscribe to this service a flat monthly fee for unlimited
       usage.

     - Chicago Board of Trade PitViper.  In June 1999, we began a limited trial
       of a wireless trade recording system, PitViper, for the Chicago Board of
       Trade. This trial allows up to 15 users of Palm devices to track and
       record trades executed on the floor. Once a trade is entered on PitViper,
       the terms of the trade are transmitted to Chicago Board of Trade's trade
       confirmation system. Traders can also access real-time price quotes for
       commodities and futures as well as news stories. We expect that the
       Chicago Board of Trade will make PitViper available to the approximately
       3,500 Chicago Board of Trade floor traders if the trial succeeds. We
       intend to charge individual subscribers a flat monthly fee for the
       service.

     - Additional financial services under development.  We are also developing
       wireless financial trading and information services for National Discount
       Brokers, Bear Stearns and TD Waterhouse Investor Services. We announced
       our agreement to build a wireless financial trading and information
       service for National Discount Brokers in November. That agreement calls
       for us to develop wireless stock-trading capability along with OmniSky's
       wireless e-mail and Internet access on Palm, WindowCE and other devices.
       The Bear Stearns project involves developing wireless trading
       applications for its brokers, clients and other financial professionals.
       We recently signed a letter of intent to develop a wireless financial
       trading and information service for TD Waterhouse. The Bear Stearns and
       TD Waterhouse projects are each in a preliminary stage, and we cannot
       assure you that definitive agreements will be signed for either of them.

     - Wireless transportation and delivery services (e-Mobile
       Delivery).  e-Mobile Delivery, a service we offer following our
       acquisition of LocusOne, allows corporations to track customer orders,
       inventory and fleet vehicle locations more efficiently. The e-Mobile
       Delivery group of products offers comprehensive ways to automate the
       point of customer contact, sales, delivery or service. These products
       integrate with corporate data systems and work using a variety of wired
       and wireless communications networks. LocusOne customers for the e-Mobile
       group of products include Physician Sales & Service, MAC Papers, Office
       Depot, NuCo2 and Suntory Water Group.

  Software Licensing

     We currently license our AIM software platform, which is the core
technology underpinning most of our wireless data services, and will license the
ScoutWare software platform when we complete our acquisition of Riverbed. We
describe these software platforms below.

     Aether Intelligent Messaging

     AIM is a package of wireless messaging software and development tools -- or
software platform -- that facilitates the development of wireless data systems.
We developed the AIM software platform in 1997 to improve the performance of
data delivery over wireless networks and to provide a development kit to speed
the software development process. We use the AIM software platform internally to
develop and support the wireless data services we offer our customers. We have
launched a program to license the AIM software platform to both software
developers and large corporations. Software developers can integrate the AIM
software platform with their applications to provide those applications with a
wireless capability. When the AIM-based application is sold, we can then earn
one-time revenue from per-user license fees or recurring revenue if the
application is run from our network operations center. Similarly,

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corporate customers who develop AIM-based applications for their own use can pay
us license fees per user or recurring services fees if we host the application.

     How the AIM Software Platform Works.  The diagram below illustrates how the
AIM software platform works to integrate sources of data with wireless networks
and devices. Data and applications come from internal corporate systems, such as
those at Morgan Stanley Dean Witter Online, from public data sources via the
Internet or from proprietary systems such as Reuters Selectfeed Plus. The AIM
software platform then takes the data, replaces unnecessary or repetitive
message-header information with more streamlined tags, compresses and encrypts
it so the data can move quickly and securely outside the security system (or
"firewall"), controlling access to and from the source's network, and then sends
it over the airwaves using any of a number of wireless networks to the intended
device. Not all devices will work on all wireless carrier networks. Our AIM
software platform can be configured to support other networks as they are
developed and as customer needs require.

                           [HOW AIM WORKS FLOW CHART]

     The AIM software platform has the following features and benefits.

     - The AIM software platform enhances the speed, efficiency and security of
       data transmission over wireless networks.  The AIM software platform
       trims unnecessary electronic message tags and compresses data, with no
       loss in the reliability of message delivery. As a result, users get data
       quickly and at a low cost. The AIM software platform uses a sophisticated
       technology known as elliptic curve cryptography, or ECC, which was
       developed by Certicom, to encode the data so it cannot be read by a third
       party that intercepts the data. Additionally, we recently reached an
       agreement to use "digital signature" technology provided by Diversinet,
       which authenticates the identity of the sender and recipient of such
       messages.

     - The AIM software platform simplifies programming required to convert data
       into a form that can be transmitted over wireless networks.  The AIM
       software platform uses industry-standard

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       programming languages and includes application program interfaces. The
       AIM software platform comes with a software development kit that provides
       programmers step-by-step guides and automatically generates code for
       major system components based on the options selected. As a result,
       programmers can focus on the business objectives the system is designed
       to meet, rather than becoming immersed in unfamiliar and complex software
       and wireless network protocols.

     - The AIM software platform facilitates the interaction of major operating
       systems on which most corporate applications run with the most widely
       used wireless data networks and devices.  To date, the AIM software
       platform is compatible with the following wireless network carrier
       protocols, mobile device operating systems and corporate operating
       systems:

        - wireless network carrier protocols: CDPD, Mobitex and ARDIS;

        - mobile device operating systems: Palm computing platform, Windows CE,
          two-way pagers and Windows 95/98/NT and their corresponding modems;
          and

        - corporate operating systems: Windows NT, Sun Solaris and Linux.

     As a result, our business customers can offer a wide variety of
applications for wireless transmission, and end users can similarly choose from
a number of devices. Our engineers continually develop the capabilities of the
AIM software platform as new protocols, devices and systems emerge.

     ScoutWare

     Through our pending acquisition of Riverbed, we plan to offer Riverbed's
ScoutWare family of software products. ScoutWare is a package of mobile data
management software and development tools that allows remote and mobile workers
to exchange information with corporate databases and the Internet. ScoutWare
also gives information technology personnel tools to manage, deploy and connect
their corporate data with handheld devices. We plan to integrate ScoutWare with
our AIM wireless integration platform, to offer customers a complete set of
wireless and mobile data solutions. ScoutWare products reside both on handheld
devices and on corporate computer servers. Mobile workers use ScoutWare when
they electronically exchange, or synchronize, data between their handheld
devices and corporate databases. There are four product categories in the
ScoutWare software suite -- ScoutSync, ScoutIT, ScoutArchitect and
ScoutWeb -- each of which is explained below:

     - ScoutSync provides the core connection between a handheld device and a
       corporate database. ScoutSync operates on both the Palm Operating System
       and the Windows CE operating system to connect to a corporate network
       using the common Internet protocol TCP/IP. Any number of remote devices
       may be simultaneously connected to a single network, and the devices can
       be a combination of Palm or Windows CE devices. ScoutSync can exchange
       information either over a wireless network or through a cradle that is
       connected to a computer linked to a corporate network. ScoutSync is made
       up of four key components, illustrated in the diagram below:

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                                    [CHART]

        (1)  ScoutSync Client, a software application that is loaded
             into the handheld device, allows the device to initiate and
             carry out a synchronization session.

        (2)  ScoutSync Server, a software application that resides on a
             computer workstation linked to the corporate network,
             allows two-way communication between a device and corporate
             data sources and lets system administrators monitor, update
             and back up remote devices.

        (3)  ScoutSync Service, a set of computerized instructions that
             resides on the ScoutSync Server, manages central processing
             components, called "conduits," enabling them to transfer
             data between the remote device and a corporation's software
             programs.

        (4)  ScoutSync Conduit, a central processing component that
             resides on a ScoutSync Server, carries out synchronization
             tasks and can access and manipulate files and databases on
             both the corporate database side and the mobile device
             side.

     - ScoutIT allows corporate information technology professionals to manage
       the interaction between corporate databases and handheld
       devices.  Residing on a Windows NT server, ScoutIT allows information
       technology managers to control how handheld devices share information
       with corporate databases. Managers can administer a system allowing
       thousands of remote devices to send and receive information from a single
       location, including backing up and restoring data to ensure security,
       upgrading and configuring applications and tracking how applications are
       being used.

     - ScoutArchitect is a package of software applications and software
       developer tools that allows developers to create mobile-ready versions of
       their corporate software applications.  ScoutArchitect allows corporate
       developers to quickly identify the most critical elements of a corporate
       software application for a handheld device. Applications can be developed
       independent of the software the device operates on or development
       environment, allowing the customer to avoid reconstruction of critical
       elements of an application when moving to different operating software or
       development

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tools. ScoutArchitect also includes programmer and application interfaces that
allow independent software vendors to write handheld device applications that
can plug into their own applications and systems.

     - ScoutWeb will allow handheld devices to receive Internet and intranet
       data.  Riverbed is developing ScoutWeb to manipulate data from the
       Internet so that the data can be effectively used on mobile devices,
       including WAP smartphones. We expect ScoutWeb will be available for
       commercial use by March 2000.

  Engineering Services

     We began operations in 1996 by providing engineering services to businesses
seeking to develop wireless data systems. Our customers have included the U.S.
Postal Service and Reuters Group Overseas Holding(UK) Limited. Our engineers
have experience in developing wireless applications for a variety of businesses.

     Since 1998, we have focused our efforts more on developing wireless data
services that will result in recurring subscription revenue to us. While we
therefore no longer provide engineering services strictly to generate revenue,
we do take on engineering assignments that might allow us to embrace
technological advances or expand into new industry sectors or services. In
addition to our contract with OmniSky, our current engineering services clients
include Response Services Center, LLC, an emergency vehicle response company,
and Merrill Lynch, Pierce, Fenner & Smith Incorporated. Through our work with
Response Services, we hope to develop new services for the transportation
industry. Through our work with Merrill Lynch, we are developing wireless
financial information services for financial professionals. We generally charge
our clients for engineering time on an hourly basis or a per project flat fee.

OMNISKY

     We believe we can provide our corporate customers with more attractive
service offerings by coupling general wireless applications like e-mail and
Internet access with custom corporate applications. Our involvement with
OmniSky, a company we formed in August 1999 with 3Com, allows us to achieve
this. OmniSky's main business objectives and strategies include those set forth
below.

     - OmniSky will pursue opportunities in the emerging consumer and business
       mass markets by developing a package of applications and services that
       includes a selection of Web sites that have been customized for access
       via wireless handheld devices, general Web browsing, access to a user's
       existing e-mail account and selected Internet and electronic transaction
       services.

     - OmniSky intends to co-market this package with wireless network carriers
       and Internet content providers in order to benefit from their brand
       recognition and marketing channels. OmniSky may also seek to bundle its
       service package with devices that are distributed by major national
       computer retailers.

     - OmniSky will seek to develop services that can access all platforms and
       devices, rather than committing to a single device or network protocol.

     - OmniSky is currently conducting a test program with approximately 6,800
       Palm V users to obtain feedback on its initial service offering. OmniSky
       expects to make this service commercially available in the second quarter
       of 2000.

     We have a 33% equity interest in OmniSky on a fully diluted basis in the
form of 10,000,000 shares of Series A Preferred Stock and 1,439,809 shares of
Series B Preferred Stock. We have a letter agreement with OmniSky to provide
engineering services through June 2000 for the design and development of
OmniSky's proposed system and services, and OmniSky has a perpetual,
royalty-free license to use our AIM software platform. Additionally, we have a
two-year right of first refusal to design and develop custom systems and
applications for all services relating to investment banking and brokerage
activities. We also have the right to bundle OmniSky services for a period of
five years as an added feature to the

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<PAGE>   51

other services we offer at a monthly cost to us of $3 per subscriber. We
describe the details of our interest in OmniSky in "Transactions Between Aether
and Its Officers, Directors and Significant Shareholders -- OmniSky" on page 68.

     Our chairman, chief executive officer and president, David S. Oros, is a
member of the OmniSky board of directors. Janice M. Roberts, one of our
directors, is also a director of OmniSky. Patrick McVeigh, former vice president
of worldwide sales for the Palm Computing division of 3Com, serves as president
and chief executive officer of OmniSky and also serves on the OmniSky board of
directors. OmniSky is based in Palo Alto, California.

OPERATIONS

  Engineering and Project Implementation

     Our most important operational resource is our engineering staff. This
staff includes wireless systems engineers, software engineers who specialize in
developing applications for handheld devices and engineers who specialize in
systems integration and testing. We have steadily built our engineering ranks
from ten in 1998 to 50 in February 2000, and with the acquisition of Riverbed we
will add 34 engineers. Many of our engineers come from engineering departments
at established companies, including IBM, Westinghouse Electric Corporation and
UPS/Roadnet. Seven of our engineers, including our chief technology officer,
comprise our research and development division. This group evaluates emerging
technologies and business opportunities and plays a key role in determining
which projects to pursue.

     Project implementation is critical to the effective delivery of services to
our customers. Projects generally consist of the following phases: project
definition, development, pilot testing, quality assurance and launch. Each
project has a project manager who works closely with the customer and
coordinates our engineers and our operations and marketing personnel through all
phases of the project. Our operations staff prepares documentation and training
manuals. During the product launch phase, we send operations teams to train
customer personnel on product use and support. Our marketing department works
closely with customers before commercial launch to coordinate advertising and
publicity.

  Technology and Network Operations

     We operate a secure network operations center at our headquarters in Owings
Mills, Maryland. We believe that this center is a vital component of our
wireless data service offerings and differentiates us from our competitors. By
outsourcing to us, our customers are relieved of the technology and operations
burden of managing a highly complex wireless data system. From our network
operations center, we maintain high speed data transmission lines (known as T1
connections) both to our customers' data sources and to the wireless data
networks we use. The center is equipped with Cisco and Hewlett-Packard
networking equipment, Sun Sparc UNIX servers and high-end clustered NT servers.
In the event of a power failure, we maintain backup power supplies, including
diesel-powered generators that are tested and serviced regularly. We believe our
network operations center is capable of meeting the security standards for
services we developed or are developing for our clients, who include Reuters,
Morgan Stanley Dean Witter Online and Charles Schwab. The center is staffed from
8:00 a.m. to 8:00 p.m. Eastern time on weekdays and is monitored 24 hours a day,
seven days a week. Through our acquisitions of Mobeo and LocusOne, we also
maintain network operation facilities in Bethesda, Maryland and Jacksonville,
Florida. We are planning to establish a backup facility in mid-2000.

     In December 1999, we established the WAP Enterprise Center. The center is
comprised of engineers who develop applications for WAP smartphones and the
systems to support data communication to these devices. The center currently is
developing WAP-enabled financial trading applications that will work with WAP
smartphones and is exploring WAP-based opportunities with wireless carriers, WAP
vendors and enterprise customers.

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  Sales and Marketing

     We are expanding our sales and marketing efforts for our services in the
financial services and other industries as well as for software licensing. As of
February 2000, we had ten sales and marketing professionals. We intend to grow
this number significantly in the next 12 months, with sales and marketing
personnel focusing on each industry we pursue, as well as a dedicated sales and
marketing team for software licensing. Our business development personnel and
senior executives also spend a considerable amount of time developing potential
customer relationships and selling and promoting our services. We intend to
spend an estimated $25 million on a branding campaign in 2000 including print
and television advertising. Our current customer segments, the services we sell
to them and how we reach them are described below.

     - Individual investors and financial market professionals.  We believe
       individual investors are the primary subscribers to our wireless
       financial information and trading services, such as MarketClip and
       TradeRunner. Print advertising in finance-related publications is our
       primary means of marketing these services. Our strategy is to share
       marketing and advertising costs with our strategic partners and corporate
       customers associated with particular services. Our customer service
       center handles in-bound calls generated from these marketing efforts and
       signs up new subscribers. We also seek to develop relationships with
       financial institutions, whose market professionals become the end users
       of our services, such as F/X Alert. We market our products through direct
       sales executives in New York, Atlanta and Chicago and through occasional
       advertising in financial trade publications.

     - Companies that track inventory, deliveries and logistics.  We target
       sales of our e-Mobile Delivery service to companies that need to track
       the movement of their drivers and inventories across broad geographic
       areas on a real-time basis. Examples of customers include Physician Sales
       & Service, MAC Papers, Office Depot, NuCo2 and Suntory Water Group. We
       work with strategic partners, including Symbol Technologies, Intermec
       Technologies Corp. and BellSouth Wireless Data to market e-Mobile
       Delivery and maintain a staff of three sales and marketing professionals
       who are located in Richmond, Virginia, Boston, Massachusetts and Atlanta,
       Georgia. We plan to expand marketing efforts through direct mail and
       advertising to transportation logistics personnel.

     - Corporate software developers and independent software vendors.  We
       target as potential licensees of our AIM software platform large
       corporations with significant mobile workforce who wish to develop their
       own wireless applications, as well as software vendors and manufacturers
       of handheld devices. After our pending acquisition of Riverbed, we will
       target the same customer segments for the ScoutWare suite of mobile data
       management products. Each of our salespeople offer AIM licensing along
       with our full array of wireless data design, development and support
       services. In our experience, corporate customers who initially sought
       only to license our AIM software have often decided to purchase complete
       wireless data communications systems and services from us. Riverbed has a
       sales team of 29 dedicated to sales of its ScoutWare software and has
       licensed this software to Palm Computing, the U.S. Postal Service, Becton
       Dickinson, Oracle and others. After our acquisition of Riverbed, our
       combined sales forces will target independent software vendors for
       licensing of both AIM and ScoutWare through conferences, trade shows,
       vendor forums and trade advertising.

     - Engineering services clients.  As part of our business development
       effort, we seek out engineering assignments that might allow us to
       embrace technological advances or expand into new industry sectors or
       services.

  Product Fulfillment, Customer Service and Billing

     We provide product fulfillment, customer service and billing at our
customer service center, located at our headquarters. We maintain a modest
inventory of mobile devices and wireless modems, which we buy in bulk from
manufacturers and resellers. Our customer service representatives first verify
that a potential subscriber will have wireless network coverage where they plan
to use the service. For qualified subscribers,
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<PAGE>   53

we load and configure custom software on mobile devices, activate wireless
modems and perform quality assurance checks. We then pack, ship and track the
product until the subscriber receives it. For end users who already own a
device, we provide only the modem and software application. We handle all repair
and warranty issues for devices we provide to our subscribers.

     We train our customer service representatives to handle inquiries about our
services, device features and wireless communications. Our customer service
personnel are available weekdays from 8:00 a.m. until 8:00 p.m. Eastern time. We
currently employ ten customer service representatives and plan to triple that
number during the first half of 2000.

     We handle customer billing for all subscription fees, device and modem
purchases, securities exchange and market fees and other charges. We bill
monthly for subscriber services, which our non-corporate customers must pay by
credit card. As a result, our billing system can support increases in our
subscriber base. We intend to enhance our billing capabilities as our needs
grow.

STRATEGIC RELATIONSHIPS

     A key to our ability to provide complete wireless data services to our
customers is our relationships with third parties. These relationships take time
to develop, and we therefore believe they provide us with an advantage by
getting our services to market before our competitors. We maintain the strategic
relationships described below.

  Wireless Network Carriers

     We believe our relationships with wireless network carriers are mutually
beneficial. We believe we are among the largest buyers of wireless data network
capacity for many of the carriers we use. As a result, we are able to negotiate
favorable rates. Typically, we have one-year contracts to buy data network
capacity either for an agreed amount of kilobytes at a flat fee or on a
cents-per-kilobyte basis. We have contracts with Metrocall, AT&T Wireless
Services, Bell Atlantic Mobile, BellSouth Wireless Data, ARDIS, SBC
Communications, Inc. and GTE Corp. As a result, we can give our customers a wide
variety of wireless carrier choices.

  Hardware and Software Vendors

     Our services increase the usefulness of wireless handheld devices, and we
believe our services will increase sales of these devices. Mobile device
manufacturers have therefore assisted us in various projects we have undertaken.
We have worked closely with 3Com, an Aether investor, on the development of our
wireless applications for the Palm personal organizer. In August 1999, a
subsidiary of Ericsson, one of the largest manufacturers of wireless phones,
agreed to assist us in developing services using WAP phones and next-generation,
high-speed GPRS data networks. In December 1999, we announced a strategic
alliance with Phone.com to jointly pursue corporate customers using Phone.com's
WAP browser technology for Web-enabled smartphones and our development and
service capabilities. We participate in industry development groups dedicated to
bringing new applications to wireless data, such as the Palm developers group,
the WAP Forum and the Windows CE developers forum.

  Financial Content Providers

     Financial content providers supply us with real-time financial information,
which we provide to our wireless data subscribers. Reuters, which is an Aether
investor, is our primary provider of financial information and market data for
MarketClip and TradeRunner. We have a license to use information from Reuters
with an initial term extending through August 2001, and the term automatically
extends each year after that unless we or Reuters decide to end the license. We
also have a license to use financial data from Bridge Information Systems
America, Inc., another financial content provider, and its subsidiary Telerate,
Inc. We have agreements with the New York Stock Exchange, the Nasdaq Stock
Market, Inc., the Chicago Board of Trade and the Options Price Reporting
Authority that authorize us to provide real-time price quotes.
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RECENT DEVELOPMENTS

  Riverbed

     On February 9, 2000, we entered into a merger agreement to acquire Riverbed
for shares of our common stock. In the merger, we will issue 4,537,286 shares of
our common stock and convert existing options held by Riverbed employees into
options to acquire shares of our common stock. If all current Riverbed options
vest and are exercised, we would be obligated to issue 862,480 shares of our
common stock. As part of the transaction, we are holding in escrow 270,000 of
the shares payable to Riverbed shareholders for 12 months to secure their
post-closing indemnification obligations to us and we have agreed to indemnify
up to $40.5 million of damages the sellers may incur. The merger agreement
provided that we will appoint two persons named by Riverbed -- E. Wayne Jackson
and Robin T. Vasan -- to our board of directors when the acquisition closes.

     Upon the acquisition of Riverbed, the shareholders of Riverbed will become
parties to the registration rights agreement we entered into at the time of our
initial public offering with several of our shareholders, and the shareholders
of Riverbed will be deemed to have equivalent rights to the original holders and
their assignees. In addition, the shareholders of Riverbed, in the aggregate,
will have the right to one additional shelf registration after October 20, 2000,
or sooner if any of the original holders sell shares sooner pursuant to Rule
144. The additional shelf registration is limited to the number of shares a
holder could sell under Rule 144.

     The closing of the acquisition is subject to approval by the shareholders
of Riverbed (substantially all of whom have agreed to vote for the transaction),
continuation of the contracts between Riverbed and Palm Computing Inc., a
subsidiary of 3Com, and customary closing conditions, and is expected to occur
by March 15, 2000.

  Reuters Strategic Alliance

     On February 8, 2000, we signed a letter of intent with Reuters to establish
a European wireless venture headquartered in the United Kingdom, which will be
initially focused on financial markets. The letter of intent provides that we
will acquire a 60% interest for $100 million and receive three of five board
seats. Dave Oros, our chief executive officer, will serve as chairman of the new
company and interim chief executive officer. The letter of intent is not binding
on us or Reuters and remains subject to definitive documentation and our
receiving money to fund the investment.

  Metrocall

     On February 8, 2000, we agreed to acquire for $10 million a 27.5% interest
in Inciscent in the form of Series A Preferred Stock. This newly-formed company
with Metrocall, PSINet, Hicks, Muse, Tate & Furst and other investors was formed
to develop wireless e-mail, Internet access and other applications for the small
office and home office market segments. Under the voting rights agreement,
Aether will have the right to appoint two of the seven directors of Inciscent.

     Upon the closing of our investment in Inciscent, we will receive
registration rights, including two demand registration rights that we can use
after the earlier of the third anniversary of closing or six months after an
initial public offering. The registration rights agreement will also grant us a
right of first offer on additional issuances of Inciscent securities.

     We will also enter into a co-sale agreement, which, among other things,
will require the holders of common stock to first offer any securities to
Inciscent and then to holders of at least 250,000 shares before selling the
securities to a third party and will further require all selling holders to
first offer their shares to holders of at least 250,000 shares. This agreement
will allow holders of at least 250,000 shares to sell a pro rata portion of
their stock to a third party along with the selling holders to the extent the
right of first refusal is not exercised. If holders of at least 66.7% of the
stock propose to sell their shares to a third party, these selling holders will
be able to force the remaining holders to participate in the sale. As part of
our closing obligations, we agreed to enter into a definitive services agreement
to provide Inciscent with a

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non-exclusive, perpetual, non-transferable license to use our AIM software
platform for $1 million, and also agreed to provide technical consulting and
development services billed on a time and materials basis. As part of the
investment we also agreed to acquire approximately 9.9% of the outstanding
capital stock of Metrocall for approximately $17 million.

  LocusOne

     On February 3, 2000, we acquired all of the capital stock of LocusOne for a
purchase price of $40 million, including the retirement of a line of credit and
payment of the legal fees of LocusOne. At closing, we paid $20 million in cash
and granted options to acquire 308,500 shares to existing LocusOne employees. At
the closing of this offering, we will be required to pay the former LocusOne
holders $5.4 million and place $13.6 million in escrow to pay all remaining
obligations, which will be paid on December 31, 2000. In connection with this
acquisition, the two principal stockholders of LocusOne have entered into
non-compete agreements with us expiring on the later of February 2, 2002 or ten
months after their termination with LocusOne.

  New Customers

     On January 12, 2000 we signed a definitive agreement with Response Services
Center, LLC to develop an emergency roadside assistance system.

     On December 28, 1999 we signed a non-binding memorandum of understanding
with TD Waterhouse to develop a wireless financial trading and information
service for its brokerage customers.

     On November 4, 1999, we signed a definitive agreement with National
Discount Brokers to provide its investors with wireless financial trading and
information services, including OmniSky e-mail and Internet access.

     On October 11, 1999, we signed an engineering services contract with
Merrill Lynch to develop a wireless financial information service for use by its
financial professionals.

  Other Strategic Alliances

     On February 15, 2000 we entered into a non-binding memorandum of
understanding with Nextel to provide wireless data services using the Nextel
wireless communications network for mobile workforces in financial services,
transportation and other industries.

     On February 7, 2000 we entered into a non-binding letter of intent with
Proxicom, an Internet consulting and development company, to jointly pursue
opportunities to provide wireless data services to companies.

     On January 27, 2000 we signed a non-binding letter of intent with
CyberBills to develop a wireless electronic bill presentment and payment
service.

     On December 21, 1999 we announced an agreement to use "digital signature"
technology provided by Diversinet.

COMPETITION

     The market for our services is becoming increasingly competitive. We
believe we offer the broadest range of services to businesses necessary to
enable the development, offering and ongoing support of wireless data
communication systems for their employees or customers. The widespread adoption
of industry standards may make it easier for new market entrants to offer some
or all of the services we offer and may make it easier for existing competitors
to introduce some or all of the services they do not now

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provide, or improve the quality of their services. We expect that we will
compete primarily on the basis of the functionality, breadth, quality and price
of our services. Our current and potential competitors include:

     - Wireless financial services providers, including W-Trade and 724
       Solutions;

     - Wireless communications software companies, including Phone.com, Nettech
       Systems Inc. and Dynamic Mobile Data;

     - Wireless data services providers, such as Wireless Knowledge, a joint
       venture of Microsoft and Qualcomm Incorporated, Research In Motion,
       GoAmerica and Saraide.com, which was recently acquired by Infospace.com;

     - Wireless systems integrators, such as IBM and GTE;

     - Wireless network carriers, such as AT&T Wireless Services, Bell Atlantic
       Mobile, Sprint PCS, Nextel Communications, Inc. and Metricom, Inc.; and

     - Mobile data management software providers, including Puma Technology,
       Inc., AvantGo, Inc. and Extended Systems, Inc.

     Many of our existing and potential competitors have substantially greater
financial, technical, marketing and distribution resources than we do.
Additionally, many of these companies have greater name recognition and more
established relationships with our target customers. Furthermore, these
competitors may be able to adopt more aggressive pricing policies and offer
customers more attractive terms than we can.

     Notwithstanding the increasing competitiveness of our market, we believe
that our potential competitors face substantial barriers to market entry.
Development of wireless data systems comparable to those we have already
developed is time consuming and costly. Moreover, the engineering talent
necessary to develop such systems is scarce.

INTELLECTUAL PROPERTY RIGHTS

     We own applications for federal registration or common law rights in the
following trademarks: AirBroker(R), Aether Technologies(TM), Aether(TM) and our
logo, Wireless Solutions for a Portable Planet(TM) Portable Planet(TM) and
e-Mobile(TM). In addition, we own federal trademark registrations for
LocusOne(TM). We do not have any federal trademark registrations in the name
"Aether," "AIM" or "e-Mobile" and we may not be able to obtain such
registrations due to conflicting marks or for other reasons. We have been
informed that another party claims intellectual property in the mark e-Mobile.
Following our acquisition of Riverbed, we will also own applications for federal
registration or common law rights in the following trademarks: Riverbed
Technologies(TM), ScoutSync(TM), ScoutWeb(TM), ScoutWare(TM), ScoutIT(TM), Free
to Go Mobile(TM) and Solutions for the Mobile Enterprise(TM). Reuters and
Reuters MarketClip(TM) are the property of Reuters Group PLC. Morgan Stanley
Dean Witter Online TradeRunner(TM) is the property of Morgan Stanley Dean Witter
Online. This prospectus also includes trade dress, trade names and trademarks of
other companies. All other brand names or trademarks appearing in this
prospectus are the property of their respective holders.

     We rely on a combination of patent, copyright, trademark, service mark,
trade secret laws and contractual restrictions to establish and protect certain
proprietary rights in our services. We have applied for a patent on our AIM
platform, which addresses the technology employed to integrate various data
sources with wireless networks and devices. Mobeo has applied for two patents
for its technology. Specifically, one patent application covers the method and
system for providing formatted information via a two-way communication system.
The other patent application covers the method and system for providing
localized information. Riverbed has applied for a patent on its ScoutWare(TM)
technology, which relates to a system and method for synchronizing information
records between a remote device and a server in a computer network. There can be
no assurances that these applications will be granted or, if granted, that
holders of other patents will not claim that the patents infringe their patents.

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     The steps taken by us to protect our intellectual property may not prove
sufficient to prevent misappropriation of our technology or to deter independent
third-party development of similar technologies. The laws of certain foreign
countries may not protect our services or intellectual property rights to the
same extent as do the laws of the United States. We also rely on certain
technologies that we and Mobeo license from third parties including data feeds
and related software from Reuters Select Feed Plus and Bridge Information
Services, synchronization technology from Riverbed and encoding technology from
Certicom. In addition, our ScoutWare software platform relies on a license of
Prism software by SpyGlass, Inc. These third-party technology licenses may not
continue to be available to us on commercially attractive terms. The loss of the
ability to use such technology could require us to obtain the rights to use
substitute technology, which could be more expensive or offer lower quality or
performance, and therefore have a material adverse effect on our business,
financial condition or results of operations.

     Third parties could claim infringement by us with respect to current or
future services. We expect that participants in our markets will be increasingly
subject to infringement claims as the number of services and competitors in our
industry segment grows. We have received two claims that we have infringed
patents developed by other parties. Although we believe these claims are without
merit, these and other intellectual property claims, with or without merit,
could be time-consuming and expensive to litigate or settle, could require us to
enter into costly royalty arrangements, could divert management attention from
administering our business and could preclude us from conducting our business.
Any such claim, whether meritorious or not, could be time-consuming, result in
costly litigation, cause service installation delays or require us to enter into
royalty or licensing agreements. Such royalty or licensing agreements might not
be available on terms acceptable to us or at all. As a result, any such claim
could have a material adverse effect upon our business, financial condition or
results of operations.

GOVERNMENT REGULATION

     We are not currently subject to direct federal, state or local government
regulation, other than regulations that apply to businesses generally. The
wireless network carriers we contract with to provide airtime are subject to
regulation by the Federal Communications Commission. Changes in FCC regulations
could affect the availability of wireless coverage these carriers are willing or
able to sell to us. We or OmniSky could also be adversely affected by
developments in regulations that govern or may in the future govern the
Internet, the allocation of radio frequencies or the placement of cellular
towers. Regulations of the SEC governing online trading could reduce the level
of online trading or the demand for wireless financial information. Also,
changes in these regulations could create uncertainty in the marketplace that
could reduce demand for our services or increase the cost of doing business as a
result of costs of litigation or increased service delivery cost or could in
some other manner have a material adverse effect on our business, financial
condition or results of operations.

     We currently do not collect sales or other taxes with respect to the sale
of services or products in states and countries where we believe we are not
required to do so. We do collect sales and other taxes in the states in which we
have offices and are required by law to do so. Some jurisdictions have sought to
impose sales or other tax obligations on companies that engage in online
commerce within their jurisdictions. A successful assertion by one or more
jurisdictions that we should collect sales or other taxes on our products and
services, or remit payment of sales or other taxes for prior periods, could have
a material adverse effect on our business, financial condition or results of
operations.

     Any new legislation or regulation, or the application of laws or
regulations from jurisdictions whose laws do not currently apply to our
business, could have an adverse effect on our business.

FACILITIES

     Our principal offices are located in Owings Mills, Maryland in a 35,018
square foot facility under a lease expiring in February 2010 with no renewal
option. We also lease an aggregate of 22,000 square feet for our offices in Boca
Raton, Florida, Jacksonville, Florida, Bethesda, Maryland, Portsmouth, New
Hampshire, New York, New York and Richmond, Virginia. Upon completion of the
acquisition of

                                       55
<PAGE>   58

Riverbed, we will acquire an additional 22,048 square feet of office space in
Vienna, Virginia and Long Beach, California.

EMPLOYEES

     As of February 15, 2000, we had a total of approximately 153 employees, and
50 of these employees were engineers. Upon the completion of our acquisition of
Riverbed, we will add 100 employees, and 34 of these employees will be
engineers. None of our employees is covered by a collective bargaining
agreement. We believe that our relations with our employees are good.

LEGAL PROCEEDINGS

     We are not currently subject to any material legal proceedings. However, we
may from time to time become a party to various legal proceedings arising in the
ordinary course of our business.

                                       56
<PAGE>   59

                                   MANAGEMENT

EXECUTIVE OFFICERS AND DIRECTORS

     Our executive officers, directors and nominees for director, and their ages
and positions will be as follows after our acquisition of Riverbed:

<TABLE>
<CAPTION>
                NAME                   AGE                      POSITION
                ----                   ---                      --------
<S>                                    <C>   <C>
David S. Oros........................  40    Chairman, Chief Executive Officer and President
George M. Davis......................  43    President, Enterprise Solutions and Services
                                             Group
E. Wayne Jackson III(1)..............  38    President, Software Products Group and Director
David C. Reymann.....................  41    Chief Financial Officer
Dale R. Shelton......................  38    Chief Technology Officer
David K. Rensin(1)...................  28    Chief Scientist
Brian W. Keane.......................  41    Senior Vice President, Business Affairs
Mitch I. Selbiger....................  41    Senior Vice President, Marketing
J. Carter Beese, Jr.(2)(3)...........  43    Director
Frank A. Bonsal, Jr.(3)..............  63    Director
Mark D. Ein..........................  35    Director
Rahul C. Prakash(2)..................  38    Director
Janice M. Roberts....................  44    Director
Dr. Rajendra Singh...................  43    Director
George P. Stamas.....................  49    Director
Robin T. Vasan(1)....................  33    Director
Devin N. Wenig.......................  33    Director
Thomas E. Wheeler(2).................  53    Director
</TABLE>

- ---------------

(1) Messrs. Jackson and Vasan have been designated by Riverbed to become
    directors immediately after the completion of the acquisition of Riverbed.
    At the same time, Messrs. Jackson and Rensin will become officers of Aether.

(2) Member of the compensation committee.

(3) Member of the audit committee.

     David S. Oros founded Aether in 1996 and has been our chairman, chief
executive officer and president since Aether's inception. Mr. Oros also serves
on the board of directors of OmniSky. From 1994 until 1996, Mr. Oros was
president of NexGen Technologies, L.L.C., a wireless software development
company that contributed all of its assets to Aether. From 1992 until 1994, he
was president of the Wireless Data Group at Westinghouse Electric. Prior to
that, Mr. Oros spent from 1982 until 1992 at Westinghouse Electric directing
internal research and managing large programs in advanced airborne radar design
and development. Mr. Oros received a B.S. in mathematics and physics from the
University of Maryland and holds a U.S. patent for a multi-function radar
system.

     George M. Davis has served as our chief operating officer since September
1997 and will be appointed as president of our enterprise solutions and services
group at the closing of the Riverbed acquisition. He joined us in September 1996
as vice president, business development to lead initiatives required to launch,
maintain and develop business opportunities for our services. From September
1994 until September 1996, Mr. Davis was director of enterprise management
systems at Northrop Grumman Corp. Prior to that time, Mr. Davis spent more than
14 years at Westinghouse Electric where he managed advanced military electronic
development and production projects. He received a B.S. in business and
economics from Bethany College.

     E. Wayne Jackson III will become president of our software products group
and a director immediately after completion of the acquisition of Riverbed.
Since October 1998, Mr. Jackson has served

                                       57
<PAGE>   60

as the president and chief executive officer and a director of Riverbed, which
he co-founded with Mr. Rensin. From September 1994 until October 1997, Mr.
Jackson served as director of the emerging technologies division of Noblestar
Systems Corp. Riverbed was created by Noblestar in 1998. He received a B.S. in
business administration, finance, from James Madison University.

     David C. Reymann has served as our chief financial officer since joining us
in June 1998. Mr. Reymann is also responsible for our treasury management
services, investor relations and human resources. Before joining us, Mr. Reymann
was director of finance and accounting for The Sweetheart Cup Company from June
1996 until May 1998, where he managed the financial analysis department and the
accounting operations for 11 North American manufacturing plants. Prior to that,
Mr. Reymann spent 12 years with Procter & Gamble serving in several key finance,
accounting and operations positions. Prior to that, Mr. Reymann spent five years
at Ernst & Young where he most recently specialized in emerging growth
companies. Mr. Reymann received a B.S. in accounting from the University of
Baltimore and is a certified public accountant.

     Dale R. Shelton has served as our chief technology officer since February
2000. From June 1996 to February 2000, he served as our senior vice president,
engineering, during which time he directed the development of AIM and our
wireless data services. From January 1994 until June 1996, Mr. Shelton served as
the systems development leader for flash-flood prediction systems at the
National Weather Service. From June 1992 until January 1994, Mr. Shelton was
principal engineer for ARINC, Inc., where he led the development of aviation
tracking and maintenance systems. He received a B.S. in computer science from
the University of Maryland.

     David K. Rensin will become our chief scientist immediately after
completion of the acquisition of Riverbed. Since October 1998, he has served as
chief technology officer of Riverbed, which he co-founded with Mr. Jackson. From
July 1995 until 1998, Mr. Rensin managed the mobile convergent group at
Noblestar Systems Co. From January 1995 to July 1995, he was a senior programmer
at American Management Systems. Mr. Rensin received a B.S. in management science
and statistics from the University of Maryland.

     Brian W. Keane has served as senior vice president, business affairs since
joining us in August 1999. Mr. Keane is responsible for mergers and
acquisitions, strategic investments, joint ventures and new strategic business
initiatives. From February 1998 until August 1999, Mr. Keane was chief financial
officer for Management Information Consulting, Inc., a technology consulting
company. Prior to that, Mr. Keane spent ten years as an investment banker with
Smith Barney Inc. Mr. Keane received a B.A. in history and mathematics from
Cornell University and an M.B.A. from Harvard Business School.

     Mitch I. Selbiger has served as our senior vice president, marketing since
January 2000. Mr. Selbiger is responsible for our advertising, branding,
marketing and public relations activities. From March 1999 until January 2000,
Mr. Selbiger served as vice president of marketing for OTG Software. Prior to
that, from July 1998 until March 1999, he served as vice president of marketing
for NetFactory. From August 1997 to July 1998, he served as director of eastern
area marketing for Netscape Communications, Inc. 1995 to 1997, he served as
director of government marketing for Sybase, Inc. Mr. Selbiger received a B.S.
in business administration from the University of Vermont and an M.B.A. from
George Washington University.

     J. Carter Beese, Jr. was elected a director of Aether on October 20, 1999.
Since July 1998, Mr. Beese has served as president of Riggs Capital Partners, a
division of Riggs National Corp., where he oversees a $100 million venture
capital fund. From September 1997 until July 1998, he served as vice chairman of
the Global Banking Group of BT Alex. Brown. Prior to the merger of Bankers Trust
and Alex. Brown, Mr. Beese was chairman of Alex. Brown International from
November 1994 until September 1997. From February 1992 until November 1994, Mr.
Beese served as a commissioner of the U.S. Securities and Exchange Commission.
Mr. Beese serves as a senior advisor to the Center for Strategic and
International Studies, a non-partisan public policy think tank and is involved
in the World Economic Forum. He serves as a director on the boards of China.com;
Internet Securities, Inc., a company majority owned by

                                       58
<PAGE>   61

Euromoney Institutional Investor, Inc.; and Natural Solutions, Inc. Mr. Beese
received a B.S. in economics and political science from Rollins College.

     Frank A. Bonsal, Jr. was elected a director of Aether on October 20, 1999.
Since 1978, Mr. Bonsal has been a founding partner of New Enterprise Associates,
one of the largest venture capital firms in the United States. Mr. Bonsal has
focused on the development of early stage companies. He currently serves as a
director on the boards of CARS, Inc., CORVIS Corp., Entevo Corp., Explore, Inc.,
GeneScreen, Inc. and Healthy Pet Inc. In addition, he is a special limited
partner of Amadeus Capital Partners, Boulder Venture, Novak Biddle, Trellis
Ventures and Windward Ventures. Mr. Bonsal received a B.A. in economics from
Princeton University.

     Mark D. Ein was a co-founder of Aether, and was elected a director of
Aether on October 20, 1999. Mr. Ein is the founder and chief executive officer
of Venturehouse Group, a holding company that was established in September 1999
to create, invest in and acquire technology and telecommunications companies.
From 1992 until September 1999, Mr. Ein was a principal with The Carlyle Group,
where he was responsible for many of its telecommunications investment
activities. Prior to joining Carlyle, Mr. Ein was an associate with Brentwood
Associates, where he worked on leveraged buyout and venture capital investments.
Prior to joining Brentwood Associates, he was an analyst in the real estate
department of Goldman, Sachs and Co. Mr. Ein currently serves as a director on
the boards of LCC International, Inc. and several private companies. Mr. Ein
received a B.S. in economics from the University of Pennsylvania and an M.B.A.
from Harvard Business School.

     Rahul C. Prakash was elected a director of Aether on October 20, 1999.
Since January 1997, Mr. Prakash has served as president of Telcom Ventures,
L.L.C., a wireless communications investment company. From January 1994 until
December 1996, Mr. Prakash served as vice president, business development of
Telcom Ventures. Prior to that time, he served as a director of business
development at LCC International, Inc., a worldwide provider of wireless
engineering and design services. From 1993 until 1994, Mr. Prakash was the
director of business development for Telemate, a joint venture he helped
establish between LCC and France Telecom. Mr. Prakash is also a director of
several private telecommunications companies controlled by Telcom Ventures. He
received an M.B.A. in international finance from American University and an
M.B.A. from the University of New Delhi, Faculty of Management Studies.

     Janice M. Roberts was elected a director of Aether on October 20, 1999.
Since September 1992, Ms. Roberts has served as senior vice president of global
marketing and business development for 3Com. She is also president of 3Com
Ventures, a corporate investment fund, and a director of OmniSky. From January
1992 until September 1992, Ms. Roberts served as vice president and general
manager for 3Com's enterprise networking division. From 1989 until January 1992,
Ms. Roberts was with BICC Communications where she held several positions,
including most recently, president and managing director of its worldwide data
networking business. Previously, she held a number of senior international
marketing, sales and business development positions in engineering, electronics
and communications-based companies. She holds an Honors degree in economics and
business from the University of Birmingham in the United Kingdom and is a member
of the Chartered Institute of Marketing.

     Dr. Rajendra Singh was elected a director of Aether on October 20, 1999.
Since December 1993, Dr. Singh has served as chairman of the board of directors
and chief executive officer of Telcom Ventures, L.L.C. From 1983 until June
1996, Dr. Singh served as chairman of the board of directors of LCC
International, Inc., which he co-founded with his wife in 1983. Dr. Singh has
played an instrumental role in the cellular industry by developing key standards
used today in wireless system design and methodology. Dr. Singh is a member of
the board of directors of Teligent, Inc. and XM Satellite Radio Holdings, Inc.
He received a Ph.D. in electrical engineering from Southern Methodist
University.

     George P. Stamas was elected a director of Aether on October 20, 1999.
Since January 2000, Mr. Stamas has served as a Vice Chair of DeutscheBanc Alex.
Brown. From April 1996 until December 1999, Mr. Stamas was a partner with the
law firm of Wilmer, Cutler & Pickering and now serves as a consultant to Wilmer,
Cutler & Pickering. From 1983 until April 1996, Mr. Stamas was a partner at
Piper
                                       59
<PAGE>   62

& Marbury L.L.P. Mr. Stamas is counsel to, and a limited partner of, the
Baltimore Orioles baseball team. Mr. Stamas also serves on the board of
directors of FTI Consulting, Inc., a provider of litigation support services,
and Luminant Worldwide Corporation, a provider of Internet consulting services.
He received a B.S. in economics from the Wharton School of the University of
Pennsylvania and a J.D. from University of Maryland Law School.

     Robin T. Vasan will be appointed as a director of Aether immediately after
completion of the acquisition of Riverbed. Since June 1998, Mr. Vasan has been a
general partner of Mayfield Fund, a venture capital fund. From June 1994 until
February 1997, he served as vice president, core technology of Risk Management
Solutions, an insurance software company. In 1997 and 1998, he attended Harvard
Business School. He received a B.A.S. in industrial engineering and economics
from Stanford University and an M.B.A. from Harvard Business School. Mr. Vasan
is a member of the board of directors of WebMethods, Inc., a
business-to-business infrastructure software and service company.

     Devin N. Wenig was elected a director of Aether on October 20, 1999. In
April 1994, Mr. Wenig joined Reuters America, Inc. and was promoted to executive
vice president of marketing in August 1998, where he is responsible for
marketing and business development for Reuters's information businesses in the
Americas. Mr. Wenig serves as a director on the boards of Loan Pricing Corp.,
Intralinks, Inc., FreeEdgar.com and Nastech Pharmaceutical Company, Inc. He
received a B.S. from Union College and a J.D. from Columbia University.

     Thomas E. Wheeler was elected a director of Aether on October 20, 1999.
Since 1992, Mr. Wheeler has served as president and chief executive officer of
the Cellular Telecommunications Industry Association. In 1994, Mr. Wheeler was
appointed by President Clinton to a six-year term as a member of the board of
trustees of the John F. Kennedy Center for the Performing Arts. Mr. Wheeler is a
director on the boards of the Public Broadcasting System and the U.S. Capitol
Historical Society. He received a B.S. in business administration from Ohio
State University.

     Following completion of the acquisition of Riverbed, our board will have
twelve directors. NexGen, Telcom-ATI Investors, L.L.C., Reuters and 3Com -- who
will together hold 55.1% of the shares of common stock outstanding after the
offering -- are parties to a stockholders agreement that governs voting for our
directors. The agreement requires each party to vote all its shares for two
directors named by NexGen, two directors named by Telcom-ATI Investors, two
directors named jointly by NexGen and Telcom-ATI Investors and one director
named by each of Reuters and 3Com. Messrs. Oros and Ein were appointed by
NexGen, Dr. Singh and Mr. Prakash were appointed by Telcom-ATI Investors, Mr.
Wenig was appointed by Reuters and Ms. Roberts was appointed by 3Com as
directors under the stockholder agreement. The terms of the stockholder
agreement are further described in "Transactions Between Aether and its
Officers, Directors and Significant Stockholders." Messrs. Jackson and Vasan
will be appointed directors of Aether when we acquire Riverbed, as required by
our acquisition agreement with Riverbed.

     Directors serve for a term of one year.

     Our executive officers are appointed by, and serve at the discretion of,
our board of directors. We expect that each of our officers will devote
substantially full time to our affairs. We expect that our non-employee
directors will devote such time to our affairs as is necessary to discharge
their duties. There are no family relationships among any of our executive
officers, directors or key employees.

COMMITTEES OF THE BOARD OF DIRECTORS

     The compensation committee consists of Messrs. Beese, Prakash and Wheeler.
The compensation committee:

     - determines the compensation of senior executive officers (such as the
       chief executive officer and chief financial officer), subject, if the
       board so directs, to the board's further ratification of the
       compensation;

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<PAGE>   63

     - determines the compensation for other officers or delegates such
       determinations to the chief executive officer;

     - grants options, stock or other equity interests under our stock option or
       other equity-based incentive plans; and

     - administers those plans and, where such plans specify, our other employee
       benefit plans.

     The audit committee consists of Messrs. Beese and Bonsal. The audit
committee:

     - makes recommendations to the board concerning the engagement of
       independent accountants;

     - reviews with the independent accountants the plans and results of the
       audit engagement;

     - approves professional services provided by the independent accountants;

     - considers the range of audit and non-audit fees;

     - verifies that auditors are independent of management and are objective in
       their findings;

     - reviews annual CPA audit and recommendations of internal controls and
       related management response;

     - reviews the audit reports with management and the auditor;

     - oversees the internal audit function; and

     - monitors management's efforts to correct deficiencies described in any
       audit examination.

DIRECTOR COMPENSATION

     Except for reimbursement for reasonable travel expenses relating to
attendance at board meetings and discretionary grants of stock options,
directors will not be compensated for their services as directors. Directors who
are employees will be eligible to participate in our equity incentive plan. We
have granted options to purchase 12,600 shares to each director and options to
purchase 4,000 shares to each member of the audit and compensation committees.
The exercise price of these options is equal to $16.00 per share. Mr. Wenig's
options are held in trust, and he currently has no beneficial interest in the
options.

     The following table identifies options that we have granted to non-employee
directors since January 1, 1997.

<TABLE>
<CAPTION>
                                         NUMBER OF
                                     SHARES UNDERLYING    EXERCISE
       NON-EMPLOYEE DIRECTOR            OPTIONS(#)        PRICE($)
       ---------------------         -----------------    --------
<S>                                  <C>                  <C>
J. Carter Beese, Jr. ..............        75,000          $ 0.40
                                           20,600           16.00
Frank A. Bonsal, Jr. ..............        37,500            1.77
                                           16,600           16.00
Mark D. Ein........................        17,500            4.00
                                           12,600           16.00
Rahul C. Prakash...................        16,600           16.00
Janice M. Roberts..................        12,600           16.00
Dr. Rajendra Singh.................        12,600           16.00
George P. Stamas...................         6,250            0.40
                                            5,000            2.40
                                           12,600           16.00
Devin N. Wenig.....................        12,600           16.00
Thomas E. Wheeler..................        37,500            1.77
                                           16,600           16.00
</TABLE>

                                       61
<PAGE>   64

EXECUTIVE COMPENSATION

     Summary Compensation.  The following table sets forth compensation for 1998
and 1999 awarded to, earned by or paid to our chief executive officer and the
four other most highly paid executive officers. We refer to these five officers
as the "named executive officers."

<TABLE>
<CAPTION>
                                                                       LONG-TERM
                                    ANNUAL COMPENSATION           COMPENSATION AWARDS
                               -----------------------------   -------------------------
                                                                                SHARES
                                                               OTHER ANNUAL   UNDERLYING     ALL OTHER
                                                               COMPENSATION    OPTIONS      COMPENSATION
 NAME AND PRINCIPAL POSITION   YEAR   SALARY ($)   BONUS ($)       ($)           (#)            ($)
 ---------------------------   ----   ----------   ---------   ------------   ----------    ------------
<S>                            <C>    <C>          <C>         <C>            <C>           <C>
David S. Oros................  1999    $200,000    $250,000           --       945,100             --
  Chairman, Chief Executive    1998     200,000     150,000           --            --             --
  Officer and President
George M. Davis..............  1999     157,292      24,504           --        55,000         $7,750
  President, Enterprise        1998     133,333      52,895       $2,420        75,000             --
  Solutions and Services
  Group
Dale R. Shelton..............  1999     129,167      20,000           --        42,500             --
  Chief Technology Officer     1998     109,200       4,000           --        50,000             --
David C. Reymann.............  1999     126,042          --           --        51,250             --
  Chief Financial Officer      1998      64,905          --           --        62,500             --
Brian W. Keane...............  1999      56,817      50,000           --       125,000             --
  Senior Vice President,       1998          --          --           --            --             --
  Business Affairs
</TABLE>

     Option Grants.  The following table shows information regarding stock
options granted to the named executive officers during the year ended December
31, 1999. No stock appreciation rights were granted to these individuals during
the year.

<TABLE>
<CAPTION>
                                                                                                   POTENTIAL REALIZABLE
                                                                                                     VALUE AT ASSUMED
                                            PERCENTAGE                                             ANNUAL RATES OF STOCK
                                             OF TOTAL                                             PRICE APPRECIATION FOR
                        NUMBER OF SHARES     OPTIONS     EXERCISE                                     OPTION TERM($)
                       UNDERLYING OPTIONS   GRANTED TO   PRICE PER       EXPIRATION       ---------------------------------------
        NAME             GRANTED(#)(*)      EMPLOYEES    SHARE($)           DATE             0%(6)         5%(7)        10%(7)
        ----           ------------------   ----------   ---------   ------------------   -----------   -----------   -----------
<S>                    <C>                  <C>          <C>         <C>                  <C>           <C>           <C>
David S. Oros........       775,000(1)        28.04%      $ 1.60          June 22, 2009   $11,160,000   $18,958,293   $30,922,407
                            157,500(1)         5.70%      $ 4.00     September 20, 2009   $ 1,890,000   $ 3,474,814   $ 5,906,231
                             12,600(2)         0.46%      $16.00       October 20, 2009   $        --   $   126,785   $   321,298
George M. Davis......        50,000(1)         1.81%      $ 1.60          June 22, 2009   $   720,000   $ 1,223,116   $ 1,994,994
                              5,000(3)         0.18%      $ 8.00     September 26, 2009   $    30,000   $    74,023   $   141,562
Dale R. Shelton......        37,500(1)         1.36%      $ 1.60          June 22, 2009   $   540,000   $   917,337   $ 1,496,245
                              5,000(3)         0.18%      $ 8.00     September 26, 2009   $    30,000   $    74,023   $   141,562
David C. Reymann.....        18,750(1)         0.68%      $ 1.60          June 22, 2009   $   270,000   $   388,668   $   678,123
                             12,500(4)         0.45%      $ 8.00       October 11, 2009   $   100,000   $   225,779   $   418,748
                             20,000(3)         0.72%      $ 8.00     September 26, 2009   $   120,000   $   296,090   $   566,248
Brian W. Keane.......       125,000(5)         4.52%      $ 4.80        August 16, 2009   $   900,000   $ 1,843,342   $ 3,290,614
</TABLE>

- ---------------

* Options expire 90 days after the termination of employment of the option
  holder.

(1) The warrants are immediately exercisable in their entirety.

(2) Fifty percent of the options will become exercisable beginning on October
    20, 2000, and the other 50% will become exercisable on October 20, 2001.
    None of the options will become exercisable prior to such dates unless there
    is a change of control of Aether, which includes a sale of all our assets or
    the sale of at least 80% of the equity of our company.

(3) The options will become immediately exercisable in their entirety on
    September 26, 2001 and none of them will become exercisable prior to that
    date unless there is a change of control of Aether, which includes a sale of
    all our assets or the sale of at least 80% of the equity of our company.

                                       62
<PAGE>   65

(4) The options will become immediately exercisable in their entirety on October
    11, 2001 and none of them will become exercisable prior to that date unless
    there is a change of control of Aether, which includes a sale of all our
    assets or the sale of at least 80% of the equity of our company.

(5) One-third of the options are immediately exercisable. The remaining
    two-thirds of the options become exercisable annually over a two-year period
    in equal one-third increments, beginning on August 16, 2000.

(6) The options listed in this column were issued with an exercise price below
    the fair market value of the option at the time of issuance.

(7) The 5% and 10% assumed annual rates of compounded stock price appreciation
    are mandated by the SEC and are based on the assumption that the exercise
    price was the fair market value of the shares on the date of grant. Prior to
    October 20, 1999, the fair market value on the date of grant was determined
    by our board of directors. There is no assurance provided to any executive
    officer or any other holder of our securities that the actual price
    appreciation over the ten-year option term will be at the assumed 5% and 10%
    levels or at any other defined level.

     Aggregate Option Exercises and Holdings.  No options were exercised by the
named executive officers during the year ended December 31, 1999. The following
table provides information concerning the shares represented by outstanding
options held by each of the named executive officers as of December 31, 1999.

<TABLE>
<CAPTION>
                                                    NUMBER OF SHARES
                                                 UNDERLYING UNEXERCISED         VALUE OF UNEXERCISED
                                                   OPTIONS AT DEC. 31,         IN-THE-MONEY OPTIONS AT
                                                         1999(#)                 DEC. 31, 1999($)(1)
                                               ---------------------------   ---------------------------
                    NAME                       EXERCISABLE   UNEXERCISABLE   EXERCISABLE   UNEXERCISABLE
                    ----                       -----------   -------------   -----------   -------------
<S>                                            <C>           <C>             <C>           <C>
David S. Oros................................    932,500         12,600      $64,920,313    $  700,875
George M. Davis..............................    175,000         80,000      $12,404,375    $5,578,250
Dale R. Shelton..............................    150,000         67,500      $10,638,751    $4,715,187
David C. Reymann.............................     39,583         74,167      $ 2,774,115    $4,600,104
Brian W. Keane...............................     41,667         83,333      $ 2,784,375    $5,568,750
</TABLE>

- ---------------

(1) Options were "in the money" because the closing price of Aether's common
    stock on December 31, 1999 exceeded the exercise price of the options. The
    value of unexercised options represents the difference between the exercise
    price of net options and $71.625, which was the last reported sale price of
    Aether common stock on December 31, 1999.

EMPLOYMENT AGREEMENTS WITH EXECUTIVE OFFICERS

     We have entered into employment contracts with Messrs. Oros and Reymann and
will enter an employment agreement with Mr. Jackson upon the closing of our
Riverbed acquisition.

     Mr. Oros' contract became effective June 22, 1999 and provides for a salary
of $200,000 per year, a performance bonus of up to $100,000 per year and
additional bonuses based on annual revenue targets and proceeds raised from
private placements of our equity securities in 1999. The contract has an initial
term expiring in June 2002 and automatically extends for additional one month
increments until terminated by Aether or Mr. Oros on 15 days notice. Pursuant to
the contract, we granted Mr. Oros a warrant to acquire 875,000 shares of our
common stock. The warrant currently has an exercise price of $1.60 per share of
common stock. We also gave Mr. Oros the right to allocate to key employees of
his choosing warrants to acquire 125,000 shares of common stock having the same
terms and conditions. Mr. Oros has awarded warrants for 50,000 shares of our
common stock to Mr. Davis, 37,500 shares of our common stock to Mr. Shelton and
18,750 shares of our common stock to Mr. Reymann. Mr. Oros subsequently received
our permission to assign part of his warrant, leaving him with a warrant to
acquire 775,000 shares. In September 1999, Mr. Oros received a warrant to
acquire 175,000 shares of our common stock at an exercise price of $4 per share.
From this grant, Mr. Oros subsequently assigned a warrant exercisable for

                                       63
<PAGE>   66

17,500 shares of our common stock. If we terminate Mr. Oros without cause, he is
entitled to receive from us an amount equal to the salary he would have received
during the balance of the term of the employment contract, and his warrants will
fully vest immediately. Under the contract, "cause" means committing an act of
gross negligence or other willful act that materially adversely affects Aether,
refusing to comply in any respect with specific directions of our board of
directors, or being convicted or pleading no contest to any felony or any
misdemeanor involving fraud, breach of trust or misappropriation. Each of these
warrants became exercisable upon completion of our initial public offering.

     Mr. Reymann's contract was entered into June 1, 1999 and provides for a
minimum salary of $127,500 per year. The contract has an initial term expiring
on June 1, 2001. We and Mr. Reymann have agreed that if we terminate him without
cause, he is entitled to receive from us an amount equal to the salary he would
have received during the balance of the term of the employment contract.

     At the closing of the Riverbed acquisition, Mr. Jackson will enter into an
employment agreement to serve as president of our software products group. The
terms of the employment agreement have not yet been determined. We and Mr.
Jackson have agreed that if we terminate him without cause, he will be entitled
to receive from us an amount equal to six months of his base salary.

1999 EQUITY INCENTIVE PLAN

     Before our initial public offering, we adopted an equity incentive plan to
promote our long-term growth and profitability, improve stockholder value and
attract, retain and reward highly motivated and qualified employees and
directors. The compensation committee of our board of directors administers the
equity incentive plan unless the board of directors specifies another committee
of the board of directors or chooses to act itself as administrator. The board
of directors has given Mr. Oros authority as a special committee of the Board to
make option grants.

     Under the equity incentive plan, we can grant options for approximately 6.9
million shares of common stock (assuming completion of the Riverbed acquisition
and this offering), which number will adjust automatically to be 20% of our
outstanding common stock from time to time. We can grant options to employees in
the form of incentive stock options for up to 3,000,000 shares, but may choose
not to do so. Any options we grant that are not incentive stock options will be
nonqualified stock options.

     All of our employees, directors and certain service providers are eligible
to receive options under the equity incentive plan. For tax reasons, the equity
incentive plan limits the number of shares covered by the options that an
individual can receive in a calendar year to 50% of the original pool. The
administrator will determine the prices, exercise schedules, expiration dates
and other material conditions under which optionees may exercise their options.
The exercise price of these options may be less than the fair market value of
the common stock on the date of grant when the administrator considers that to
be appropriate. We replaced the options Aether Systems LLC granted with options
under this plan when we converted to a corporation before completion of our
initial public offering.

     All options will become exercisable if we have a change of control, except
as option agreements provide otherwise or as necessary to allow pooling of
interest accounting. The plan's administrator may provide that an optionee must
cooperate with us in connection with the change of control to receive this
acceleration. In general, we will have a change of control if:

     - anyone acquires or holds at least 80% of our voting securities, excluding
       holdings by our benefit plans and some other related parties;

     - we complete a merger or consolidation, unless, in general, our pre-merger
       shareholders own more than 20% of the voting securities of the merged
       companies;

     - our board changes in specified ways in connection with proxy contests or
       as a result of adding new directors who are not approved by existing
       directors; or

     - if we complete a liquidation or dissolution or sell or otherwise dispose
       of all or substantially all of our assets.
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In addition, unless we provide otherwise, or as necessary to allow pooling of
interest accounting, the equity incentive plan and all options will terminate in
defined circumstances if:

     - we are not the surviving company in a merger, consolidation or
       reorganization;

     - we complete a liquidation or dissolution or sell substantially all our
       assets; or

     - our board approves and we complete a transaction that results in a person
       or entity's owning all of our stock, unless the person or entity is
       related to us in specified ways.

However, before the equity incentive plan would terminate for one of those
reasons, we would either agree that our successor would assume the options
and/or the equity incentive plan, allow optionees to exercise the options if
these options were in-the-money, or cancel the options by paying the amount, if
any, by which the value determined with respect to that transaction exceeds the
exercise price of the options.

     The equity incentive plan limits the time during which an optionee can
exercise an option to no more than ten years. In addition, an optionee who
leaves employment will generally have no more than 90 days to exercise an
option, reduced to no days after employment in terminations for cause, and
additional rules apply to death and disability. The compensation committee may,
however, override the plan's rules, other than the ten year limit. We cannot
grant additional options under the equity incentive plan after September 20,
2009.

SENIOR BONUS PLAN

     We adopted a senior bonus plan before our initial public offering. A
special tax rule in Section 162(m) of the Internal Revenue Code of 1986, as
amended, limits the compensation that we can deduct for payments to our chief
executive officer and the four other most highly compensated executive officers
to $1 million per officer per year. We intend the senior bonus plan to provide
incentive compensation that does not count against each executive's deduction
limit. We may choose to use the senior bonus plan, or we may pay bonuses under
some other future plan to which the tax deduction limits will apply, as long as
we do not use the other payments to make up bonuses a participant loses under
the senior bonus plan.

     Unless our board of directors selects another committee, the compensation
committee administers the senior bonus plan and selects participants from our
key employees and those of any subsidiaries, although we expect that most
participants will be executive officers. When we refer to the "compensation
committee" in discussing the senior bonus plan, we also mean any other committee
that administers this plan. Only "outside directors" under the tax rules can
determine the participants, set the performance goals and certify that we or the
participants have met those goals. The compensation committee consists solely of
two outside directors and one director affiliated with a 5% stockholder. The
compensation committee has broad administrative authority to, among other
things, designate participants, establish performance goals and performance
periods, determine the effect of participant termination of employment and
"change in control" transactions before paying an award, and generally interpret
and administer the senior bonus plan. Neither we nor the board has designated
any participants or established any performance goals under the senior bonus
plan.

     The compensation committee will select participants for any given time
period based primarily on its judgment as to which executive officers are likely
to be named in our proxy statement as the chief executive officer or one of our
other four most highly compensated executive officers as of the end of the
performance period and that the compensation committee reasonably expects to
have compensation in excess of $1 million. None of our employees exceeded that
limit in 1999.

     In setting performance goals, the compensation committee will specify the
applicable performance criteria and targets it will use for such performance
period, which may vary from participant to participant.

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The performance criteria and targets will measure one or more of the following
company, subsidiary, operating unit or division financial performance measures:

     - pre-tax or after-tax net income or earnings;

     - earnings before interest expense, taxes, depreciation and amortization;

     - operating income or gross revenue;

     - profit or operating margin;

     - earnings per share;

     - stock price;

     - cash flows;

     - total stockholder return;

     - total stockholder return as compared to total return, on a comparable
       basis, of a publicly available index such as the Standard & Poor's 500
       Stock Index;

     - return on equity, on capital or on investment;

     - ratio of debt to stockholders' equity;

     - subscriber growth;

     - working capital; or

     - strategic business criteria consisting of one or more objectives based
       upon meeting specified revenue, market penetration, geographic business
       expansion goals, cost targets and goals relating to acquisitions or
       divestitures.

     The compensation committee may set these goals (1) on an absolute
stand-alone basis, or on a relative basis in comparison to others, (2) based on
internal targets, (3) based on comparison with prior performance, (4) based on
comparison to capital, shareholders' equity, shares outstanding, assets or net
assets, and/or (5) based on comparison to the performance of other companies.
For example, the compensation committee could express an income-based
performance measure in a number of ways, such as net earnings per share, or
return on equity or with reference to meeting or exceeding a specific target, or
with reference to growth above a specified level, such as prior year's
performance or peer group performance. The compensation committee can also
ignore unusual or nonrecurring accounting effects. The senior bonus plan
provides that achieving these goals must be substantially uncertain at the time
the goals are established and are subject to the committee's right to reduce the
amount of any award payable as a result of the performance as discussed below.

     The compensation committee may set a participant's target bonus, that is,
the amount the participant will receive if the targets are met, as a dollar
amount or in a formula, for example as a percentage share of a bonus pool,
provided that, if the committee uses a pool approach, the total bonus
opportunity for all participants who are part of the pool may not total more
than 100% of the pool. The committee has the sole discretion to reduce, but not
increase, the actual bonus awarded under the plan. The committee must determine
the extent to which the performance goals are met and the participant becomes
entitled to a bonus.

     The maximum bonus payable under the senior bonus plan to any one individual
in any one calendar year is $3 million, although we have no plans or
expectations at this time to pay bonuses of that size.

     Our board or the committee may at any time amend the senior bonus plan, and
our board may terminate the plan. However, without a participant's written
consent, no amendment or termination may materially adversely affect the annual
bonus rights, if any, of any already designated participant for a given
performance period after the participants and targets are set. Our board may
make any amendments necessary to comply with applicable regulatory requirements,
including the tax deduction limit for senior
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executives. If necessary to preserve the intended tax treatment, the board may
submit future amendments of the senior bonus plan to our shareholders for
approval.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

     None of the members of our compensation committee is an officer or employee
of Aether. None of our executive officers serves as a member of the board of
directors or compensation committee of any entity that has one or more executive
officers serving on our board of directors or compensation committee.

LIMITATION OF LIABILITY AND INDEMNIFICATION MATTERS

     Our certificate of incorporation limits the liability of directors to the
maximum extent permitted by Delaware law. Delaware law provides that a director
of a corporation will not be personally liable for monetary damages for breach
of an individual's fiduciary duties as a director except for liability:

     - for any breach of a director's duty of loyalty to Aether or to its
       stockholders;

     - for acts or omissions not in good faith or that involve intentional
       misconduct or a knowing violation of law;

     - for unlawful payments of dividends or unlawful stock repurchases or
       redemptions as provided in Section 174 of the Delaware General
       Corporation Law; or

     - for any transaction from which a director derives an improper personal
       benefit.

     Our bylaws provide that Aether will indemnify its directors and executive
officers and may indemnify its officers, employees and other agents to the full
extent permitted by law. We believe that indemnification under our bylaws will
cover at least negligence and gross negligence on the part of an indemnified
party. Our bylaws also permit us to advance expenses incurred by an indemnified
party in connection with the defense of any action or proceeding arising out of
a party's status or service as a director, officer, employee or other agent of
Aether upon an undertaking by the party to repay the advances if it is
ultimately determined that he or she is not entitled to indemnification.

     We entered into separate indemnification agreements with each of our
directors and officers. These agreements require us to, among other things,
indemnify the director or officer against expenses (including attorney's fees),
judgments, fines and settlements paid by the individual in connection with any
action, suit or proceeding arising out of the individual's status or service as
a director or officer of Aether (other than liabilities arising from willful
misconduct or conduct that is knowingly fraudulent or deliberately dishonest)
and to advance expenses incurred by the individual in connection with any
proceeding against the individual with respect to which he or she may be
entitled to indemnification by us.

     We believe that our certificate of incorporation and bylaw provisions and
indemnification agreements are necessary to attract and retain qualified persons
as directors and officers. We also maintain directors' and officers' liability
insurance.

     At present we are not aware of any pending litigation or proceeding
involving any director, officer, employee or agent of Aether where
indemnification will be required or permitted. Furthermore, we are not aware of
any threatened litigation or proceeding that might result in a claim for
indemnification.

     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers or persons controlling our company
pursuant to the foregoing provisions, we have been informed that, in the opinion
of the SEC, such indemnification is against public policy as expressed in the
Securities Act and is therefore unenforceable.

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                      TRANSACTIONS BETWEEN AETHER AND ITS
                OFFICERS, DIRECTORS OR SIGNIFICANT STOCKHOLDERS

     Since January 1, 1997, we have engaged in the following transactions with
executive officers, directors and owners of 5% or more of our equity, or
entities related to them.

EQUITY INVESTMENTS

     The following discussion describes the issuance of equity interests in
connection with the initial capitalization of our predecessor, Aether Systems,
LLC, and subsequent financings. Immediately prior to our initial public offering
on October 26, 1999, we converted into a Delaware corporation at which time,
each holder of units in our limited liability company was converted into two and
one-half shares of our common stock and each option or warrant for one unit was
converted into an option or warrant for two and one-half shares of our common
stock. The discussion below gives only the number of shares into which units
were converted.

     Aeros L.L.C., our predecessor, was formed in January 1996 by NexGen
Technologies, L.L.C. and a predecessor to Transettlements, Inc. At the time
Aeros was formed, NexGen contributed assets in the wireless data field in
exchange for 7,500,000 shares and Transettlements contributed $1,000,000 in cash
in exchange for 2,500,000 shares. In May 1996, Transettlements contributed an
additional $500,000 in exchange for an additional 1,250,000 shares. In August
1996, we changed our name to Aether Technologies International, L.L.C. Then, in
September 1999, we changed our name to Aether Systems, LLC.

     In February 1997, a subsidiary of Telcom Ventures, L.L.C. acquired 725,000
shares from Transettlements and 107,500 shares from NexGen and contributed
$1,000,000 to Aether in exchange for 1,562,500 shares. Additionally, Telcom
Ventures was granted an option to purchase 1,775,000 shares from Transettlements
and two options to purchase a total of 2,267,500 shares from NexGen. In December
1997, Telcom Ventures and its subsidiary contributed an additional $690,369 to
Aether in exchange for an additional 575,308 shares. In June 1999, Telcom
Ventures exercised its option with Transettlements and one of its options with
NexGen to purchase 1,775,000 and 392,500 shares, respectively. Aether did not
receive any proceeds from the exercise of these options.

     In October 1997, we borrowed $100,000 from Reuters Group Overseas Holdings
(UK) Limited pursuant to a demand note that accrued interest at 7% per year. In
January 1998, we borrowed an additional $100,000 from Reuters at an accrued
interest rate of 7% per year pursuant to a second demand note. In March 1998, as
part of the consideration paid by Reuters for Aether's development of
MarketClip, Reuters cancelled both of these notes.

     In January 1998, Pyramid Ventures, Inc., a subsidiary of Bankers Trust
Corporation, acquired 833,333 shares at $1.20 per share and 1,004,903 shares at
$1.49 per share for total proceeds to Aether of approximately $2.5 million. At
that time, Aether redeemed 208,333 shares held by NexGen for $249,999 and
625,000 shares held by Transettlements for $750,000. As part of the financing
arrangement, Pyramid agreed to use reasonable efforts (1) to cause BT Alex.
Brown to purchase 100 subscriptions to MarketClip for a 12-month period or (2)
to refer affiliates of BT Alex. Brown or third parties to Aether for the purpose
of entering into development contracts with an aggregate price of $300,000 over
a two-year period.

     In June 1998, Telcom Ventures and Pyramid each loaned us $250,000. The
notes accrued interest at 8% per year and were due on demand with a stated
maturity date of the earlier of December 31, 1998 or the closing of an
anticipated private placement of units. The notes were convertible into shares
at the option of the holder at the rate of $250,000 divided by the per share
price to be paid in the anticipated private placements. In connection with the
issuance of these notes, we also issued warrants to acquire 14,140 shares with
an exercise price of $0.01 per share to each of Telcom Ventures and Pyramid.
Pyramid converted its $250,000 loan plus accrued interest in August 1998 to
142,950 shares at a per share price of $1.77 and exercised its warrant and
acquired 14,140 shares. In August 1998, we repaid the amount owed

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Telcom Ventures, including $2,520 in interest. In August 1999, Telcom Ventures
exercised its warrant and acquired 14,140 shares at a per share price of $0.01.

     In August 1998, Reuters received 2,828,055 shares in exchange for
$4,735,020 in cash and forgiveness of $530,980 we owed Reuters for hardware and
other inventory, offset by $266,000 Reuters owed us under a license agreement we
previously entered into with Reuters relating to sales of MarketClip and related
fees.

     In October 1998, 3Com Corp. contributed $6,000,000 in exchange for
2,500,000 shares. At the same time, we issued 3Com a conditional warrant to
purchase 893,665 shares exercisable at $0.01 per share if the milestones
described below are achieved before October 20, 2001. 3Com achieved the first
milestone entitling it to exercise 143,665 shares as a result of having
completed a joint sales and marketing plan. 3Com may exercise an additional
375,000 shares if and when we receive $6 million in engineering services revenue
from business opportunities introduced by 3Com. 3Com may exercise an additional
375,000 shares if we attain 6,000 wireless service subscribers as a result of
business opportunities introduced to us by 3Com. 3Com has not attained either of
these last two milestones and has not exercised any of its warrants.

     Effective June 1999, we issued to Mr. Oros a warrant to acquire 875,000
shares at an exercise price of $.01 per share. We subsequently agreed with Mr.
Oros to amend the exercise price to $1.60 per share. We also gave Mr. Oros the
right to allocate to key employees of his choosing warrants to acquire 125,000
shares having the same terms and conditions. Mr. Oros has awarded warrants to
acquire 50,000 shares to Mr. Davis, 37,500 shares to Mr. Shelton and 18,750
shares to Mr. Reymann. Mr. Oros subsequently received our permission to
subdivide his warrant to give Mark Ein a warrant to acquire 100,000 shares,
leaving Mr. Oros with a warrant to acquire 775,000 shares. In September 1999,
when we increased the exercise price on the warrants issued to Mr. Oros in June
1999, we granted Mr. Oros a warrant to acquire an additional 175,000 shares at
an exercise price of $4 per share to compensate him for the increase in the
exercise price on the earlier warrants. From this grant, Mr. Oros subsequently
assigned a warrant exercisable for 17,500 shares to Mr. Ein.

     In August 1999, we issued to Mr. Ein 100,000 shares upon exercise of his
options at an exercise price of $0.40 per share. In September 1999, Mr. Beese
exercised an option for 75,000 shares at an exercise price of $0.40 per share.

     NexGen, Telcom-ATI Investors, Reuters and 3Com entered into a stockholder
agreement under which these parties vote for two directors named by each of
NexGen and Telcom-ATI Investors and for one director named by each of Reuters
and 3Com. In addition, commencing on the date of the first annual meeting of
stockholders, if the board of directors consists of up to nine members, these
parties will vote to elect to the board of directors one additional person named
jointly by NexGen and Telcom-ATI Investors Ventures; and if the board of
directors consists of 10 or more members, the parties will vote to elect two
members named jointly by NexGen and Telcom-ATI Investors. In connection with the
acquisition of Riverbed, these stockholders will amend the stockholder agreement
to allow for a board of 12 members. The right to name directors will end when
parties to the agreement reduce their share ownership below levels set forth in
the agreement.

     We entered into a registration rights agreement with NexGen, Telcom-ATI
Investors, Reuters, 3Com and Transettlements, which entitles these parties to an
aggregate of three demand registrations at any time after October 27, 2000, and
at the request of these parties, to include in any registration statement for
our own account or the account of any other stockholder, the shares of common
stock held by those parties, subject to limitations set forth in the agreement.
The agreement also requires us to file a shelf registration statement covering
the sale of all shares held by parties to the stockholder agreement from time to
time. The agreement requires us to file the shelf registration statement only
when we are eligible to use the short form registration statement on Form S-3,
which would be no earlier than October 20, 2000. Upon the acquisition of
Riverbed, the shareholders of Riverbed will become parties to this registration
rights agreement under which the shareholders of Riverbed and their assignees
will have equivalent rights to the original holders and their assignees
thereunder. In addition, the shareholders of Riverbed and their assignees, in
the aggregate, will have the right to one additional shelf registration after
October 20, 2000
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(or earlier if the original holders sell shares in reliance on Rule 144)
provided that the sales by any Riverbed shareholder or assignee under such
additional right will not exceed the amount that would be permitted under Rule
144(e) if the one year holding period had expired.

LOAN TO NEXGEN

     In September 1998, we loaned NexGen $155,000 at an interest rate of 7.5%
per year pursuant to two notes. One note for $95,000 was due in December 1998,
and one note for $60,000 was due in October 1998. In August 1999, both notes
were amended to be due upon 30 days notice. On December 24, 1998, NexGen made a
payment of $19,346 with respect to these notes. On February 15, 2000, NexGen
made an additional payment of $151,716 in full satisfaction of the notes.

REUTERS LICENSE AGREEMENT

     In August 1998, we entered into an amended license, marketing and
distribution agreement with Reuters, which continues through August 11, 2001 and
renews automatically for successive one-year terms unless either party provides
180 days prior written notice. Reuters granted us a non-exclusive license to use
the information supplied by Reuters Selectfeed Plus for distribution to
subscribers of MarketClip, AirBroker and for development purposes. In August
1999, Reuters granted us permission to use Selectfeed Plus information for the
TradeRunner service developed for Morgan Stanley Dean Witter Online and other
services we are developing. Pursuant to the agreement, Aether granted Reuters an
exclusive license to use the systems developed by Aether to transmit Reuters
information to wireless handheld devices and a license to use the MarketClip
software for purposes of supplying subscribers with MarketClip. The geographic
scope of all of the licenses under the agreement is limited to the United
States. Under the agreement, Reuters has a right of first refusal to purchase
shares of Aether if Aether or any stockholder sells shares and, as a result, a
competitor of Reuters holds 50% or more of our shares, or if we sell all or
substantially all of our assets to a competitor of Reuters. Under the terms of
the license, we pay Reuters a monthly fee for each subscriber to our services
that uses information provided by Reuters. During 1998 we paid Reuters $40,300
under this contract and the average monthly fee per subscriber was $4.89; during
1999 we paid Reuters $122,356 under this contract and the average monthly fee
per subscriber was $8.02.

OMNISKY

     On August 9, 1999, we formed a new company with 3Com in which we acquired
an interest in AirWeb Corporation, which was doing business as OpenSky and is
currently known as OmniSky Corporation. We contributed a perpetual,
non-exclusive, non-assignable, royalty-free worldwide license to our AIM
software platform in exchange for 7,000,000 shares of Series A Preferred Stock.
In connection with the formation of OmniSky, 3Com paid $7.0 million in cash and
agreed to contribute to OmniSky a perpetual, non-exclusive, non-assignable
license to 3Com's Web Clipping technology (including rights to derivative works)
and Palm OS software in exchange for 10,000,000 shares of Series A Preferred
Stock, which initially represented a 33% equity interest in OmniSky on a fully
diluted basis. The management team of OmniSky acquired in the aggregate 4.2
million shares of common stock and options to acquire an additional 5.8 million
shares. Following our initial public offering, we exercised a warrant to acquire
an additional 3,000,000 shares of Series A Preferred Stock for $2,500,000
increasing our equity interest in OmniSky to 33% on a fully diluted basis. In
January 2000, we exercised our right of first refusal to maintain our 33% equity
interest by acquiring 1,439,809 shares of Series B Preferred Stock for $6.7
million, net of the cancellation of approximately $613,000 of indebtedness owed
by OmniSky to us. 3Com did not exercise its right of first offer and thus its
33% interest has been diluted.

     As part of our investment with 3Com in OmniSky, we each received
registration rights, including two demand registration rights that we can use
after the earlier of the completion of OmniSky's initial public offering and
August 9, 2004. We also entered into a right of first refusal and co-sale
agreement, which, among other things, requires the management team to first
offer any OmniSky securities to OmniSky and then to us and 3Com before selling
the securities to a third party. This agreement also allows us and 3Com to sell
a pro rata portion of our stock to a third party along with the management team
if the right
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of first refusal is not exercised. We and 3Com have also agreed that before
either of us sells any shares of Series A Preferred Stock to an unrelated third
party, we would first offer the other (or any other holders of Series A
Preferred Stock) those shares on a pro rata basis and then offer their shares to
OmniSky.

     Aether, 3Com and OmniSky's management are each entitled to appoint one
director to OmniSky's board of directors. OmniSky's board of directors currently
includes: David S. Oros, our chairman, chief executive officer and president and
Janice M. Roberts, who is one of our directors. We have entered into a voting
agreement with 3Com and OmniSky's management in which each of the parties has
agreed to vote in favor of each of the directors named by Aether, 3Com and
OmniSky's management until the earliest of (1) OmniSky's completion of an
initial public offering of at least $15 million, (2) OmniSky's completion of a
sale of substantially all of the assets of OmniSky or the transfer of more than
50% of the voting power of OmniSky or (3) the parties' termination of the
agreement. OmniSky cannot take certain major corporate actions, such as selling
the company or issuing securities with rights and preferences senior to the
Series A Preferred Stock, without the approval of holders of two-thirds of the
Series A Preferred Stock.

     On August 9, 1999, we entered into a letter agreement with OmniSky under
which we have agreed to provide OmniSky, for a period of ten months from the
date of the letter agreement, engineering services for the design and
development of its proposed systems and services. The letter agreement
originally provided that OmniSky will pay us $250,000 per month for these
services but we subsequently amended it to be on a time and materials basis. In
addition, they paid us $500,000 for work performed prior to the date of the
letter agreement. Additionally, for a period of five years from the date of the
letter agreement, OmniSky has agreed to provide us the right to resell OmniSky's
basic package of services. We also have a right of first refusal for development
of all investment banking and brokerage applications for OmniSky for a period of
two years from the date of the letter agreement, subject to approval of the
company for whom the service is developed.

     In October 1999, we agreed to purchase 25,000 Minstrel V modems from
OmniSky for a price per modem of $230, which was OmniSky's cost. OmniSky has an
exclusive buying arrangement with Novatel for Minstrel V modems, which runs
through March 2000. We have paid for 20,000 of the 25,000 modems in two
installments: $1,400,000 on October 15, 1999 and $3,200,000 on November 15,
1999. The modems are being delivered to us through April of 2000.

RIVERBED

     On February 9, 2000, we entered into a merger agreement with Riverbed for
an aggregate of 5.4 million shares of our common stock. We agreed to issue
4,537,286 million shares in exchange for the outstanding shares of Riverbed
capital stock and to reserve an additional 862,480 shares of our common stock
for issuance upon exercise of options issued to Riverbed employees. Immediately
after the closing, E. Wayne Jackson, the chairman and chief executive officer of
Riverbed, will become the president of our software products group and a
director of Aether and Robin T. Vasan, a director of Riverbed, will become a
director of Aether. In addition, Mr. Jackson will enter into an employment
agreement which includes a provision restricting him from competing with us or
Riverbed, for one year following his termination. As part of the closing,
licensing fees for our AIM software platform that have been incurred by Riverbed
will no longer be payable.

REUTERS

     On February 8, 2000, we entered into a letter of intent with Reuters under
which we will contribute $100 million for 60% of a new European company. Under
the letter of intent, Reuters will own the remaining 40% through a contribution
of assets and $22 million in cash. David S. Oros, our chief executive officer,
will serve as chairman and interim chief executive officer of the new company.
This letter of intent is non-binding, and there is no assurance that we will
successfully complete definitive documentation with respect to this transaction.

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                       PRINCIPAL AND SELLING STOCKHOLDERS

     The following table sets forth certain information with respect to
beneficial ownership of our common stock as of February 15, 2000 (assuming
completion of the Riverbed acquisition), and as adjusted to reflect the sale of
2,346,219 shares of common stock offered in this offering (assuming no exercise
of the over-allotment option) and the closing of the Riverbed acquisition, as
to:

     - each person (or group of affiliated persons) known by us to own
       beneficially more than 5% of our outstanding common stock;

     - each stockholder selling shares of our common stock in this offering;

     - each of our directors and persons we have identified will become
       directors;

     - each of the executive officers named in the summary compensation table;
       and

     - all our directors and executive officers as a group.

     Except as indicated in the footnotes to this table and under applicable
community property laws, to our knowledge, the persons named in the table have
sole voting and investment power with respect to all shares of common stock.
Options exercisable on or before April 30, 2000, are included as shares
beneficially owned. For the purposes of calculating percent ownership as of
February 15, 2000, 34,509,687 shares were issued and outstanding (assuming
completion of the Riverbed acquisition) and, for any individual who beneficially
owns shares represented by options exercisable on or before April 30, 2000,
these shares are treated as if outstanding for that person, but not for any
other person. Unless otherwise indicated, the address of each of the individuals
and entities named below is: c/o Aether Systems, Inc., 11460 Cronridge Drive,
Owings Mills, Maryland 21117.

<TABLE>
<CAPTION>
                                           BENEFICIAL OWNERSHIP OF                   BENEFICIAL OWNERSHIP OF
                                         SHARES BEFORE THE OFFERING                 SHARES AFTER THE OFFERING
                                         ---------------------------   SHARES TO    -------------------------
           NAME AND ADDRESS                 NUMBER         PERCENT     BE SOLD**      NUMBER        PERCENT
           ----------------              -------------    ----------   ----------   -----------   -----------
<S>                                      <C>              <C>          <C>          <C>           <C>
DIRECTORS AND EXECUTIVE OFFICERS:
David S. Oros(1).......................    7,724,168         23.6%         30,000    7,524,376         21.9%
George M. Davis(2).....................      175,000             *         30,000      145,000             *
Dale R. Shelton(3).....................      150,000             *         30,000      120,000             *
David C. Reymann.......................       39,583             *         15,000       24,583             *
Brian W. Keane.........................       41,667             *         15,000       26,667             *
David K. Rensin........................      204,780             *          5,119      199,661             *
  c/o Riverbed Technologies, Inc.
  2070 Chain Bridge Road
  Vienna, VA 22182
Mitch I. Selbiger......................            0             *              0            0             *
Frank A. Bonsal, Jr.(4)................       42,250             *              0       42,250             *
  1119 St. Paul Street
  Baltimore, MD 21202
J. Carter Beese(5).....................       77,500             *              0       77,500             *
Mark D. Ein(6).........................      217,500             *              0      217,500             *
E. Wayne Jackson III...................      195,862             *         24,897      170,965             *
  6608 Corine Court
  Columbia, MD 21044
Rahul C. Prakash(7)....................        2,000             *              0        2,000             *
  c/o Telcom Ventures, L.L.C.
  211 N. Union St., Suite 300
  Alexandria, VA 22314
Janice M. Roberts(8)...................            0             *              0            0             *
  c/o 3Com Corporation
  5400 Bayfront Plaza
  Santa Clara, CA 95952
</TABLE>

                                       72
<PAGE>   75

<TABLE>
<CAPTION>
                                           BENEFICIAL OWNERSHIP OF                   BENEFICIAL OWNERSHIP OF
                                         SHARES BEFORE THE OFFERING                 SHARES AFTER THE OFFERING
                                         ---------------------------   SHARES TO    -------------------------
           NAME AND ADDRESS                 NUMBER         PERCENT     BE SOLD**      NUMBER        PERCENT
           ----------------              -------------    ----------   ----------   -----------   -----------
<S>                                      <C>              <C>          <C>          <C>           <C>
Dr. Rajendra Singh(9)..................    7,026,948           22%              0    6,851,274         19.9%
  c/o Telcom Ventures, L.L.C.
  211 N. Union St., Suite 300
  Alexandria, VA 22314
George P. Stamas(10)...................       11,250             *          5,000        6,250             *
  c/o DeutscheBanc Alex. Brown
  One South Street
  Baltimore, MD 21202
Robin T. Vasan(11).....................            0             *              0            0             *
  c/o Mayfield Fund
  2800 Sand Hill Road
  Menlo Park, CA 94025
Devin N. Wenig.........................            0             *              0            0             *
  c/o Reuters America, Inc.
  1700 Broadway, 2nd Floor
  New York, NY 10019
Thomas E. Wheeler(12)..................       47,500             *              0       42,500             *
All directors and executive officers as
  a group
  (18 persons)(13).....................   15,956,006         49.8%        500,507   15,455,499         43.0%
5% AND SELLING STOCKHOLDERS:
3Com Corporation(14)...................    2,643,665          8.2%              0    2,643,665          7.7%
  5400 Bayfront Plaza
  Santa Clara, CA 95052
NexGen Technologies, L.L.C.............    6,791,668         21.2%        169,792    6,621,876         19.3%
Pyramid Ventures, Inc.(15).............    1,995,325          6.2%         49,883    1,945,442          5.7%
  One Bankers Trust Plaza
  130 Liberty Street
  New York, NY 10006
Reuters MarketClip Holdings Sarl(16)...    2,828,055          8.8%              0    2,828,055          8.2%
  c/o Reuters America, Inc.
  1700 Broadway, 2nd Floor
  New York, NY 10019
Telcom-ATI Investors, L.L.C.(17).......    7,026,948         20.7%        175,674    6,851,274         19.9%
  211 N. Union St., Suite 300
  Alexandria, VA 22314
Columbia Capital LLC...................    1,448,590          4.5%         36,215    1,412,375          4.1%
  201 North Union Street, Suite 300
  Alexandria, VA 22314
FBR Technology Venture Partners L.P....      935,345          2.9%         23,384      911,961          2.6%
  11600 Sunrise Valley Drive, Suite 460
  Reston, VA 20191
Mayfield Fund L.P......................      996,997          3.1%         24,925      972,072          2.8%
  2800 Sand Hill Road
  Menlo Park, CA 94025
Noblestar Systems Corp.................      592,729          1.9%         14,818      577,911          1.7%
  Two Reston Overlook
  12021 Sunset Hills Road, Suite 600
  Reston, VA 20190
Paul Opalack(18)(19)...................      613,494          1.9%            101      613,393          1.7%
Steven Roth............................       26,593             *            665       25,928             *
  34 Pepperell Court
  Bethesda, MD 20817
Joe Nardone(18)........................       24,622             *            616       24,006             *
</TABLE>

                                       73
<PAGE>   76

<TABLE>
<CAPTION>
                                           BENEFICIAL OWNERSHIP OF                   BENEFICIAL OWNERSHIP OF
                                         SHARES BEFORE THE OFFERING                 SHARES AFTER THE OFFERING
                                         ---------------------------   SHARES TO    -------------------------
           NAME AND ADDRESS                 NUMBER         PERCENT     BE SOLD**      NUMBER        PERCENT
           ----------------              -------------    ----------   ----------   -----------   -----------
<S>                                      <C>              <C>          <C>          <C>           <C>
Kate June Opalack(18)..................        5,571             *            139        5,432             *
Matthew Paul Opalack(18)...............        5,571             *            139        5,432             *
Nancy W. Opalack(18)...................        5,571             *            139        5,432             *
Elizabeth Ruth Rensin Irrevocable
  Trust(18)............................        2,972             *             74        2,898             *
Paul Pocialik(18)......................        2,066             *             52        2,014             *
Joan H. and E. Wayne Jackson, Jr.......        1,486             *             37        1,449             *
  P.O. Box 1487
  8381 Raymond Brown Lane
  (Route 705)
  Gloucester, VA 23061
The Adam Wayne Jackson Irrevocable
  Trust(18)............................        1,486             *             37        1,449             *
The Audrey Louise Jackson Irrevocable
  Trust(18)............................        1,486             *             37        1,449             *
The Nicholas Wayne Jackson Irrevocable
  Trust(18)............................        1,486             *             37        1,449             *
</TABLE>

- ---------------
  *  Less than 1%.

**  Shares set forth in this column are shares to be sold by the person named
    and do not include shares over which the named person has indirect
    beneficial ownership.

 (1) Includes 6,791,668 shares owned by NexGen Technologies, L.L.C. over which
     Mr. Oros exercises voting and investment control by virtue of his position
     as Managing Member of NexGen. Also includes warrants to purchase 932,500
     shares of common stock.

 (2) Includes vested options to purchase 125,000 shares of common stock and
     warrants to purchase 50,000 shares of common stock.

 (3) Includes vested options to purchase 112,500 shares of common stock and
     warrants to purchase 37,500 shares of common stock.

 (4) The amount shown excludes approximately 18,170 shares in which Mr. Bonsal
     has an indirect interest as a result of his non-voting limited liability
     company membership interest in Telcom-ATI Investors and excludes the
     indirect interest Mr. Bonsal has in 6,713 shares Telcom-ATI Investors has
     the right the acquire.

 (5) The amount shown excludes approximately 103,825 shares in which Mr. Beese
     has an indirect interest as a result of his non-voting limited liability
     company membership interest in Telcom-ATI Investors and excludes the
     indirect interest Mr. Beese has in 38,355 shares Telcom-ATI Investors has
     the right to acquire.

                                       74
<PAGE>   77

 (6) Includes warrants to purchase 100,000 shares of common stock and warrants
     to purchase 17,500 shares of common stock at $4 per share.

 (7) Mr. Prakash, the president of Telcom-ATI Investors, (which is controlled by
     Telcom Ventures, LLC), disclaims beneficial ownership of the 5,151,948
     shares owned by Telcom-ATI Investors including approximately 52,000 shares
     in which he has an indirect interest as a result of his option to acquire a
     non-voting limited liability company membership interest in Telcom-ATI
     Investors and the indirect interest Mr. Prakash has in approximately 19,000
     shares Telcom-ATI Investors has the right to acquire.

 (8) Ms. Roberts is senior vice president global marketing and business
     development of 3Com Corp. and president of 3Com Ventures. Ms. Roberts
     disclaims beneficial ownership of shares held by 3Com Corp.

 (9) Includes 5,151,948 shares owned by Telcom-ATI Investors and entities it
     controls, and an additional 1,875,000 shares which Telcom-ATI Investors has
     the right to acquire over which Dr. Singh exercises voting and investment
     control by virtue of his position as chairman and chief executive officer
     of Telcom-ATI Investors.

(10) Includes vested options to purchase 11,250 shares of common stock. The
     amount shown excludes approximately 15,572 shares in which Mr. Stamas has
     an indirect interest as a result of his non-voting limited liability
     company membership interest in Telcom-ATI Investors and excludes the
     indirect interest Mr. Stamas has in 5,753 shares Telcom-ATI Investors has
     the right to acquire. Mr. Stamas also disclaims beneficial ownership of the
     1,995,325 shares beneficially owned by Pyramid Ventures, Inc., an affiliate
     of Deutsche Banc Alex. Brown.

(11) Mr. Vasan is a partner with Mayfield Fund. Mr. Vasan disclaims beneficial
     ownership of shares held by Mayfield Fund except to the extent of any
     pecuniary interest.

(12) Includes vested options to purchase 37,500 shares of common stock. Also
     includes 5,000 shares owned by the Carol and Tom Wheeler Foundation of
     which Mr. Wheeler is the trustee.

(13) Includes all the shares and options identified above and options for 20,833
     shares and 62,500 shares issuable upon exercise of options exercisable by
     April 30, 2000.

(14) Includes vested warrants to purchase 143,665 shares of common stock.

(15) Pyramid Ventures, Inc. is an indirect wholly-owned subsidiary of
     DeutscheBank AG.

(16) Reuters MarketClip Holdings Sarl is an indirect wholly-owned subsidiary of
     Reuters Group PLC.

(17) Includes an option to acquire 1,875,000 shares of common stock from NexGen
     at a price of $1.92 per share.

(18) c/o Riverbed Technologies, Inc.
     2070 Chain Bridge Road
     Vienna, VA 22182

(19) Includes (i) 592,729 shares owned by Noblestar Systems Corp. over which Mr.
     Opalack exercises voting and investment control by virtue of his position
     as President and 90% shareholder, (ii) 5,571 shares owned by his wife,
     (iii) 5,571 shares owned by his son, and (iv) 5,571 shares owned by his
     daughter. Mr. Opalack disclaims beneficial ownership over the 16,713 shares
     held by his wife, son and daughter.

                                       75
<PAGE>   78

                          DESCRIPTION OF CAPITAL STOCK

     Our authorized capital stock consists of 75,000,000 shares of common stock,
$.01 par value, and 1,000,000 shares of preferred stock, $.01 par value.

COMMON STOCK

     As of February 15, 2000 assuming the completion of the Riverbed
acquisition, there were 32,018,468 shares of common stock outstanding that were
held of record by approximately 19 recordholders. As of the same date, there
were options and warrants to purchase a total of 4,875,054 shares of common
stock assuming completion of the acquisition of Riverbed. As of February 15,
2000, assuming the completion of our Riverbed acquisition, there would be
34,509,687 shares of common stock outstanding (assuming no exercise of the
underwriters' over-allotment option) after giving effect to the sale of the
shares of common stock offered by this prospectus. After completion of the
concurrent offering of convertible notes there will be convertible notes
outstanding that are convertible into an aggregate of
shares of common stock.

     The holders of common stock are entitled to one vote per share on all
matters to be voted upon by the stockholders. Subject to preferences that may be
applicable to any outstanding preferred stock, the holders of common stock are
entitled to receive ratably any dividends that may be declared from time to time
by the board of directors out of funds legally available therefor. In the event
of a liquidation, dissolution or winding up of Aether, the holders of common
stock are entitled to share ratably in all assets remaining after payment of
liabilities, subject to prior rights of holders of preferred stock, if any, then
outstanding. The common stock has no preemptive or conversion rights or other
subscription rights. There are no redemption or sinking fund provisions
available to the common stock. All outstanding shares of common stock are fully
paid and non-assessable.

PREFERRED STOCK

     Aether is authorized to issue 1,000,000 shares of undesignated preferred
stock. The board of directors has the authority to issue the undesignated
preferred stock in one or more series and to determine the powers, preferences
and rights and the qualifications, limitations or restrictions granted to or
imposed upon any wholly unissued series of undesignated preferred stock and to
fix the number of shares constituting any series and the designation of a
series, without any further vote or action by the stockholders. The issuance of
preferred stock may have the effect of delaying, deferring or preventing a
change in control of Aether without further action by the stockholders and may
adversely affect the voting and other rights of the holders of common stock.
Furthermore, this preferred stock may have other rights, including economic
rights senior to the common stock, and, as a result, the issuance of preferred
stock could have a material adverse effect on the market value of the common
stock. At present, we have no plans to issue any shares of preferred stock.

STOCKHOLDER'S AGREEMENT

     NexGen, Telcom-ATI Investors, Reuters and 3Com entered into a stockholders
agreement which requires these parties to vote to elect to the board of
directors two persons named by each of NexGen and Telcom-ATI Investors, two
persons named jointly by NexGen and Telcom-ATI Investors and one person named by
each of Reuters and 3Com. We describe the terms of this agreement in further
detail in "Transactions Between Aether and its Officers, Directors or
Significant Stockholders" on page 68.

REGISTRATION RIGHTS OF STOCKHOLDERS

     We and NexGen, Telcom-ATI Investors, Reuters, 3Com, J. Carter Beese, Jr.
and Mark D. Ein entered into a registration rights agreement requiring us to
register their shares on demand beginning October 27, 2000. Following our
acquisition of Riverbed, the former Riverbed stockholders will become parties to
this agreement. We describe the terms of this agreement in further detail in
"Transactions Between Aether and its Officers, Directors or Significant
Stockholders" on page 68.
                                       76
<PAGE>   79

ANTI-TAKEOVER PROVISIONS OF DELAWARE LAW AND CHARTER PROVISIONS

     Our certificate of incorporation and bylaws contain provisions that are
intended to enhance the likelihood of continuity and stability in the
composition of our board of directors and in the polices formulated by our board
of directors. In addition, provisions of Delaware law may hinder or delay an
attempted takeover of Aether other than through negotiation with our board of
directors. These provisions could have the effect of discouraging attempts to
acquire us or remove incumbent management even if some or a majority of our
stockholders believe this action to be in their best interest, including
attempts that might result in the stockholders' receiving a premium over the
market price for the shares of common stock held by stockholders.

     Removal and replacement of directors.  Under our certificate of
incorporation and bylaws, directors may only be removed with cause. In addition,
a majority of the directors then in office can fill board vacancies and
newly-created directorships resulting from any increase in the size of the board
of directors, even if those directors do not constitute a quorum or only one
director is left in office. These provisions could prevent stockholders,
including parties who want to take over or acquire us, from removing incumbent
directors without cause and filling the resulting vacancies with their own
nominees.

     Advance notice provisions for stockholder proposals and stockholder
nominations of directors.  The bylaws establish an advance notice procedure
regarding stockholder proposals and nominations for director. The advance notice
procedure will not apply to proposals by our board of directors or management.
Any stockholder that wishes to make a proposal or nominate a director for
election at an annual meeting must deliver us notice of the proposal or the
nomination not less than 45 days nor more than 90 days before the first
anniversary of the proxy statement for the preceding year's annual meeting. For
a special meeting, the notice must generally be delivered not less than 70 days
nor more than 90 days before a special meeting or ten days following the day on
which public announcement of the meeting is first made. This advance notice
proposal could prevent someone interested in acquiring us from proposing actions
that could facilitate the takeover.

     Special meetings of stockholders and actions in lieu of a meeting.  Our
certificate of incorporation and bylaws permit special meetings of the
stockholders to be called only by the board of directors, the chairman of the
board or the president or holders of at least 50% of our securities that are
outstanding and entitled to vote generally in an election of directors. The
stockholders may take action by written consent in lieu of a meeting only if
such consent is signed by all stockholders. These provisions may make it more
difficult for stockholders to take actions opposed by the board of directors.

     Authorized but unissued shares.  Without further stockholder approval, we
can issue shares of common stock and preferred stock up to the number of shares
authorized for issuance in our certificate of incorporation, except as limited
by Nasdaq rules. We could use these additional shares for a variety of corporate
purposes. These purposes include future public offerings to raise additional
capital, corporate acquisitions and employee benefit plans. Our ability to issue
these shares of common stock and preferred stock could make it more difficult,
or discourage an attempt, to obtain control of Aether by means of a proxy
contest, tender offer, merger or otherwise.

     Amendment of bylaws.  The Delaware General Corporation Law generally
provides that the affirmative vote of a majority of the shares entitled to vote
on any matter is required to amend a corporation's certificate of incorporation
or bylaws, unless the corporation's certificate of incorporation or bylaws, as
the case may be, requires a greater percentage. Our certificate of incorporation
and bylaws require the affirmative vote of the holders of at least 66 2/3% of
our outstanding voting stock to amend or repeal our bylaws. Our bylaws may also
be amended or repealed by a simple majority vote of the board of directors.

     Section 203 of Delaware Law.  In addition to the foregoing provisions of
our certificate of incorporation and bylaws, we will be subject to the
provisions of Section 203 of the Delaware General Corporation Law. In general,
the statute prohibits a publicly-held Delaware corporation from engaging in a
"business combination" with an "interested stockholder" for a period of three
years after the date that the

                                       77
<PAGE>   80

person became an interested stockholder unless (with exceptions) the business
combination or the transaction in which the person became an interested
stockholder is approved in a prescribed manner. Generally, a "business
combination" includes a merger, asset or stock sale or other transaction
resulting in a financial benefit to the stockholder, and an "interested
stockholder" is a person who, together with affiliates and associates, owns (or
within three years prior, did own) 15% or more of the corporation's outstanding
voting stock. This provision may have the effect of delaying, deferring or
preventing a change in control of Aether without further action by the
stockholders. Transactions with NexGen or Telcom-ATI Investors or their
affiliates are not covered by this provision.

     Our stock option plan generally provides for assumption of our plan or
substitution of an equivalent option of a successor corporation or,
alternatively, at the discretion of the board of directors, exercise of some or
all of the options stock, including non-vested shares, or acceleration of
vesting of shares issued pursuant to stock grants, upon a change of control or
similar event. The ability to accelerate vesting may make a takeover more
expensive and thus discourage a takeover attempt.

WARRANTS

     As of the date of this prospectus, warrants were outstanding for the
purchase of 2,068,665 shares of common stock. Of these warrants, warrants for
1,000,000 shares are exercisable at a price of $1.60 per share and 175,000
warrants are exercisable at a price of $4.00 per share. 3Com holds the remaining
warrants to purchase 893,665 shares at a price of $.01 per share. The warrants
exercisable for $1.60 per share and the warrants exercisable for $4.00 per share
are currently exercisable and remain exercisable until June 2002. The remaining
warrants become exercisable from time to time upon the satisfaction of
conditions described on page 69 of this prospectus.

TRANSFER AGENT AND REGISTRAR

     The transfer agent and registrar for our common stock is BankBoston, N.A.

LISTING

     Our shares of common stock are quoted on the Nasdaq National Market under
the symbol "AETH."

                                       78
<PAGE>   81

                   UNITED STATES FEDERAL TAX CONSEQUENCES TO
                        NON-U.S. HOLDERS OF COMMON STOCK

GENERAL

     The following is a general discussion of the material U.S. federal income
and estate tax consequences of the ownership and disposition of our common stock
by a non-U.S. holder. As used in this discussion, a "non-U.S. holder" is any
person other than:

     - a citizen or resident of the United States,

     - a corporation or other entity created or organized in or under the laws
       of the United States, any state thereof, or the District of Columbia,

     - an estate the income of which is subject to U.S. federal income taxation
       regardless of its source, or

     - a trust that is subject to the primary supervision of a U.S. court and
       the control of one or more U.S. persons.

     This discussion is based on the Internal Revenue Code of 1986, as amended,
(the "Code"), U.S. Treasury regulations, and administrative and judicial
interpretations thereof, all of which may be subject to change, possibly with
retroactive effect. This discussion does not address all aspects of U.S. federal
income and estate taxation that may be relevant to a particular non-U.S. holder
in light of the holder's particular circumstances or to non-U.S. holders that
may be subject to special rules. This discussion also does not address the tax
consequences arising under the laws of any state, local, or non-U.S.
jurisdiction.

     THE FOLLOWING DISCUSSION IS INCLUDED IN THIS PROSPECTUS ONLY FOR GENERAL
INFORMATION. ACCORDINGLY, YOU SHOULD CONSULT YOUR TAX ADVISOR REGARDING THE U.S.
FEDERAL, STATE, LOCAL AND NON-U.S. TAX CONSEQUENCES OF HOLDING AND DISPOSING OF
SHARES OF OUR COMMON STOCK.

     An individual may be deemed to be a resident alien of the United States, as
opposed to a nonresident alien, by virtue of being present in the United States
for at least 31 days in the calendar year and for an aggregate of at least 183
days during the three-year period ending in the current calendar year. In
determining the 183-day period, all of the days in the current year are counted,
one-third of the days in the preceding year are counted, and one-sixth of the
days in the second preceding year are counted. Resident aliens are subject to
U.S. federal income and estate taxes in the same manner as U.S. citizens and
residents.

DIVIDENDS

     In the event that we pay dividends on our common stock, dividends paid to a
non-U.S. holder will generally be subject to a U.S. withholding tax at a rate of
30 percent, unless an applicable income tax treaty were to provide for a lower
withholding rate. You should consult your tax advisor regarding your entitlement
to benefits under a relevant income tax treaty.

     Dividends that (1) are effectively connected with a non-U.S. holder's
conduct of a trade or business in the U.S. and (2) if an income tax treaty
applies, attributable to a permanent establishment or, in the case of an
individual, a "fixed base" in the United States as provided in that treaty are
subject to U.S. federal income tax on a net income basis at graduated rates, and
are exempt from the 30 percent withholding tax if the non-U.S. holder files the
appropriate U.S. Internal Revenue Service ("IRS") form with the payor. In
addition, if received by a non-U.S. holder that is a corporation, those
dividends may also, under certain circumstances, be subject to an additional
"branch profits tax" at a 30 percent rate or such lower rate as may be specified
by an applicable income tax treaty.

     Dividends paid prior to January 1, 2001 to an address in a foreign country
are presumed, absent actual knowledge to the contrary, to be paid to a resident
of that country for purposes of the withholding

                                       79
<PAGE>   82

tax discussed above and for purposes of determining the applicability of a tax
treaty rate. For dividends paid after December 31, 2000:

     - a non-U.S. holder of our common stock who claims the benefit of an
       applicable income tax treaty rate generally will be required to satisfy
       applicable certification and other requirements,

     - in the case of Class A common stock held by a foreign partnership, the
       certification requirement will generally be applied to the partners of
       the partnership and the partnership will be required to provide certain
       information, including a U.S. taxpayer identification number, and

     - look-through rules will apply for tiered partnerships.

     A non-U.S. holder may obtain a refund of any excess amounts withheld by
filing an appropriate claim for refund along with the required information with
the IRS.

GAIN ON DISPOSITION OF COMMON STOCK

     A non-U.S. holder generally will not be subject to U.S. federal income tax
or withholding requirements with respect to gain recognized on the disposition
of our common stock unless one of the following situations applies:

     - The gain is (1) effectively connected with a U.S. trade or business of
       the non-U.S. holder or a U.S. partnership, trust, or estate in which the
       non-U.S. holder is a partner or beneficiary, and (2) if required by an
       applicable tax treaty, the gain is attributable to a permanent
       establishment or fixed base of the non-U.S. holder in the United States.
       In these cases, the non-U.S. holder will generally be taxed on its net
       gain at regular graduated U.S. federal income tax rates, unless an
       applicable treaty provides otherwise. If, in these cases, the non-U.S.
       holder is a foreign corporation, it may be subject to an additional
       "branch profits tax" at a 30 percent rate or such lower rate as may be
       specified by an applicable tax treaty.

     - The non-U.S. holder is an individual who holds the common stock as a
       capital asset within the meaning of section 1221 of the Code and who is
       present in the United States for 183 or more days in the taxable year of
       the disposition and meets certain other requirements. In such a case,
       unless an applicable treaty provides otherwise, the non-U.S. holder would
       generally be subject to a flat 30 percent tax on the net gain derived
       from the sale, which gain, along with other capital gains from U.S.
       sources, may be offset by capital losses of the non-U.S. holder for the
       taxable year from sources within the United States.

     - The non-U.S. holder is subject to tax pursuant to the provisions of U.S.
       tax law applicable to certain expatriates.

     - We are, or have previously been, a "United States real property holding
       corporation" for U.S. federal income tax purposes at any time during the
       shorter of (1) the five-year period preceding the non-U.S. holder's
       disposition of our common stock, or (2) the period during which the
       non-U.S. holder held the common stock. In such a case, the non-U.S.
       holder would be subject to U.S. federal income tax on its net gain at
       regular graduated rates, except as described below. Generally, a
       corporation is a United States real property holding corporation if the
       fair market value of its interests in U.S. real property represents 50
       percent or more of the fair market value of its worldwide real property
       interests plus other assets used or held for use in a trade or business.
       We do not believe that we are or ever have been, nor do we anticipate
       becoming, a United States real property holding corporation for U.S.
       federal income tax purposes. In the event that we were to become a United
       States real property holding corporation, any gain realized by a non-U.S.
       holder that directly or indirectly held 5 percent or less of our
       outstanding common stock at all times during the applicable period would
       not be subject to tax if such stock were "regularly traded" on an
       established securities market. If our common stock were not treated as
       regularly traded, the purchaser of such stock from any non-U.S. holder
       would be required to withhold 10 percent of the proceeds of the sale
       unless we could certify that we are not and were not during the
       applicable period a United States real property holding corporation.

                                       80
<PAGE>   83

FEDERAL ESTATE TAX

     For U.S. federal estate tax purposes, an individual's gross estate will
include common stock owned, or treated as owned, by that individual at the time
of his or her death. This is generally the case regardless of whether such
individual was a U.S. citizen or resident. Thus, such common stock owned by
non-U.S. holders may be subject to U.S. federal estate tax, unless an applicable
estate tax or other treaty limits such an inclusion.

INFORMATION REPORTING AND BACKUP WITHHOLDING TAX

     Generally, we must report annually to the IRS and to each non-U.S. holder
the amount of dividends paid to such holder and the tax withheld with respect to
such dividends. These information reporting requirements apply regardless of
whether withholding is required. Copies of these information returns may also be
made available to the tax authorities in the country in which the non-U.S.
holder is a resident under provisions of an applicable income tax treaty or
agreement.

     Dividends paid to a non-U.S. holder at an address within the United States
may be subject to backup withholding at a rate of 31 percent if the non-U.S.
holder fails to establish that it is entitled to an exemption or to provide a
correct taxpayer identification number and other information to the payor. Under
currently applicable law, non-U.S. holders of common stock generally will be
exempt from backup withholding on dividends paid prior to January 1, 2001 to an
address outside the United States. For dividends paid after December 31, 2000,
however, a non-U.S. holder of common stock that fails to certify its non-U.S.
holder status in accordance with applicable U.S. Treasury regulations may be
subject to backup withholding at a rate of 31 percent on payments of dividends.

     The payment by or through a United States office of a broker of the
proceeds of a sale of our common stock generally will be subject to both backup
withholding and information reporting unless the holder certifies to the payor
its status as a non-U.S. holder under penalties of perjury or otherwise
establishes an exemption.

     Information reporting and backup withholding generally will not apply to a
payment by or through a foreign office of a foreign broker of the proceeds of a
sale of our common stock effected outside the United States. However,
information reporting requirements, but currently not backup withholding, will
apply to a payment by or through a foreign office of a broker of the proceeds of
a sale of our common stock effected outside the United States if that broker:

     - is a United States person for U.S. federal income tax purposes;

     - is a foreign person that derives 50 percent or more of its gross income
       for certain periods from the conduct of a trade or business in the United
       States;

     - is a "controlled foreign corporation" as defined in the Code; or

     - is a foreign partnership with certain U.S. connections (for payments made
       after December 31, 2000).

     Information reporting requirements will not apply in the above cases if the
broker has documentary evidence in its records that the holder is a non-U.S.
holder and certain conditions are met or the holder otherwise establishes an
exemption. In addition, effective after December 31, 2000, backup withholding
may apply to the payment of disposition proceeds by or through a non-U.S. office
of a broker in the above cases unless certain certification requirements are
satisfied or an exemption is otherwise established and the broker has no actual
knowledge or reason to know that the holder is a U.S. person. Non-U.S. holders
should consult their own tax advisors regarding the application of the
information reporting and backup withholding rules to them, including changes to
these rules that will become effective after December 31, 2000.

     Amounts withheld under the backup withholding rules do not constitute a
separate United States federal income tax. Rather, any amounts withheld under
the backup withholding rules will be refunded or allowed as a credit against the
holder's U.S. federal income tax liability, if any, provided the required
information or appropriate claim for refund is filed with the IRS.

                                       81
<PAGE>   84

                        SHARES ELIGIBLE FOR FUTURE SALE

     Future sales of substantial amounts of common stock, including shares
issued upon exercise of outstanding options and warrants or conversion of
outstanding convertible notes, in the public market following this offering
could adversely affect market prices prevailing from time to time and could
impair our ability to raise capital through sale of our equity securities. Sales
of substantial amounts of our common stock in the public market after the
restrictions lapse could adversely affect the prevailing market price and our
ability to raise the equity capital in the future.

     As of February 15, 2000, assuming the completion of this offering and our
pending acquisition of Riverbed, we would have outstanding 34,509,687 shares of
common stock. Of these shares, 10,414,187 shares (including the 3,000,000 shares
to be sold in this offering (10,573,395 shares if the underwriters'
over-allotment option is exercised in full)), will be freely tradable in the
public market without restriction under the Securities Act, unless the shares
are held by "affiliates" of Aether, as that term is defined in Rule 144 under
the Securities Act.

     Of the 34,509,687 shares outstanding upon completion of this offering and
our pending acquisition of Riverbed, 24,095,500 will be "restricted securities"
as that term is defined under Rule 144. We issued and sold these restricted
securities in private transactions in reliance on exemptions from registration
under the Securities Act. Restricted securities may be sold in the public market
only if they are registered or if they qualify for an exemption from
registration under Rule 144 or Rule 701 under the Securities Act, as summarized
below.

     Pursuant to "lock-up" agreements, all directors of Aether have agreed with
the underwriters not to offer, sell, contract to sell, grant any option to
purchase or otherwise dispose of any of the 1,466,440 shares they hold or have
the right to acquire (or additional shares they may acquire) for a period of 90
days from the date of this prospectus. Pursuant to "lock-up" agreements, major
stockholders and all the executive officers of Aether have agreed with the
underwriters not to offer, sell, contract to sell, grant any option to purchase
or otherwise dispose of any of the 25,776,079 shares they hold or have the right
to acquire (or additional shares they may acquire) until October 21, 2000. We
also have entered into an agreement with the underwriters that we will not
offer, sell or otherwise dispose of common stock for a period of 90 days from
the date of this prospectus. However, Merrill Lynch & Co. may in its sole
discretion, at any time without notice, consent to the release all or any
portion of the shares subject to lock-up agreements.

     Taking into account the lock-up agreements, and assuming Merrill Lynch &
Co. does not release stockholders from these agreements, the following shares
will be eligible for sale in the public market at the following times:

     - on the date of this prospectus, 10,414,187 shares (10,573,395 shares if
       the underwriters' over-allotment option is exercised in full) will be
       immediately available for sale in the public market;

     - 90 days after the date of the prospectus, approximately 19,250 shares
       will be eligible for sale;

     - on October 26, 2000, 19,671,646 shares will be eligible for sale under
       Rule 144; and

     - at various times after October 26, 2000, 4,423,854 shares will be
       eligible for sale under Rule 144.

     In general, under Rule 144, after the expiration of the lock-up period, a
person who has beneficially owned restricted securities for at least one year
would be entitled to sell, within any three-month period, a number of shares
that does not exceed the greater of:

     - 1% of the then-outstanding shares of common stock; or

     - the average weekly trading volume of the common stock during the four
       calendar weeks preceding the sale.

                                       82
<PAGE>   85

     Sales under Rule 144 are also subject to manner of sale and notice
requirements and to the availability of current public information about Aether.
Under Rule 144(k), a person who has not been our affiliate at any time during
the three months before a sale and who has beneficially owned the shares
proposed to be sold for at least two years can sell these shares without
complying with the manner of sale, public information, volume limitation or
notice provisions of Rule 144.

     Through February 15, 2000, we have outstanding options and warrants to
purchase 4,012,574 shares of common stock to specified persons pursuant to our
equity incentive plan. We also will be issuing options to acquire approximately
862,480 shares of our common stock in connection with the acquisition of
Riverbed. We have filed a registration statement on Form S-8 to register
5,400,000 shares of common stock reserved for issuance under our equity
incentive plan. See "Management -- Executive Compensation" on page 60. Shares
issued under the foregoing plan may be sold in the open market, subject, in the
case of some holders, to the Rule 144 limitations applicable to affiliates, the
lock-up agreements and vesting restrictions imposed by us.

     In addition, following this offering, the holders of 23,920,501 shares of
outstanding common stock will, under some circumstances, have rights to require
us to register their shares for future sale. See "Description of Capital
Stock -- Registration Rights of Stockholders" on page 76.

                                       83
<PAGE>   86

                                  UNDERWRITING

GENERAL

     We intend to offer the shares in the U.S. and Canada through the U.S.
underwriters and elsewhere through the international managers. Merrill Lynch,
Pierce, Fenner & Smith Incorporated, FleetBoston Robertson Stephens Inc.,
Donaldson, Lufkin & Jenrette Securities Corporation, U.S. Bancorp Piper Jaffray
Inc., Bear, Stearns & Co. Inc. and Friedman, Billings, Ramsey & Co., Inc. are
acting as U.S. representatives of the U.S. underwriters named below. Subject to
the terms and conditions described in a U.S. purchase agreement among us, the
selling stockholders and the U.S. underwriters, and concurrently with the sale
of 450,000 shares to the international managers, we and the selling stockholders
have agreed to sell to the U.S. underwriters, and the U.S. underwriters
severally have agreed to purchase from us and the selling stockholders, the
number of shares listed opposite their names below.

<TABLE>
<CAPTION>
                                                                              NUMBER
               U.S. UNDERWRITER                                              OF SHARES
               ----------------                                              ---------
<S>            <C>                                                           <C>
Merrill Lynch, Pierce, Fenner & Smith
               Incorporated................................................
FleetBoston Robertson Stephens Inc.........................................
Donaldson, Lufkin & Jenrette Securities Corporation........................
U.S. Bancorp Piper Jaffray Inc.............................................
Bear, Stearns & Co. Inc....................................................
Friedman, Billings, Ramsey & Co., Inc......................................
                                                                             ---------
               Total.......................................................  2,550,000
                                                                             =========
</TABLE>

     We and the selling stockholders have also entered into an international
purchase agreement with the international managers for sale of the shares
outside the U.S. and Canada for whom Merrill Lynch International, FleetBoston
Robertson Stephens International Limited, Donaldson, Lufkin & Jenrette
International, U.S. Bancorp Piper Jaffray Inc., Bear, Stearns International
Limited and Friedman, Billings, Ramsey International, Ltd. are acting as lead
managers. Subject to the terms and conditions in the international purchase
agreement, and concurrently with the sale of 2,550,000 shares to the U.S.
underwriters pursuant to the U.S. purchase agreement, we and the selling
stockholders have agreed to sell to the international managers, and the
international managers severally have agreed to purchase 450,000 shares from us
and the selling stockholders. The initial public offering price per share and
the total underwriting discount per share are identical under the U.S. purchase
agreement and the international purchase agreement.

     The U.S. underwriters and the international managers have agreed to
purchase all of the shares sold under the U.S. and international purchase
agreements if any of these shares are purchased. If an underwriter defaults, the
U.S. and international purchase agreements provide that the purchase commitments
of the nondefaulting underwriters may be increased or the purchase agreements
may be terminated. The closings for the sale of shares to be purchased by the
U.S. underwriters and the international managers are conditioned on one another.

     We and the selling stockholders have agreed to indemnify the U.S.
underwriters and the international managers against certain liabilities,
including liabilities under the Securities Act, or to contribute to payments the
U.S. underwriters and international managers may be required to make in respect
of those liabilities.

     The underwriters are offering the shares, subject to prior sale, when, as
and if issued to and accepted by them, subject to approval of legal matters by
their counsel, including the validity of the shares, and other conditions
contained in the purchase agreements, such as the receipt by the underwriters of
officer's certificates and legal opinions. The underwriters reserve the right to
withdraw, cancel or modify offers to the public and to reject orders in whole or
in part.

                                       84
<PAGE>   87

COMMISSIONS AND DISCOUNTS

     The U.S. representatives have advised us and the selling stockholders that
the U.S. underwriters propose initially to offer the shares to the public at the
initial public offering price on the cover page of this prospectus and to
dealers at that price less a concession not in excess of $     per share. The
U.S. underwriters may allow, and the dealers may reallow, a discount not in
excess of $     per share to other dealers. After the public offering, the
public offering price, concession and discount may be changed.

     The following table shows the public offering price, underwriting discount
and the proceeds before expenses to us and the selling stockholders. This
information assumes either no exercise or full exercise by the U.S. underwriters
and the international managers of their over-allotment options.

<TABLE>
<CAPTION>
                                                       PER SHARE    WITHOUT OPTION    WITH OPTION
                                                       ---------    --------------    -----------
<S>                                                    <C>          <C>               <C>
     Public offering price...........................     $              $                 $
     Underwriting discount...........................     $              $                 $
     Proceeds, before expenses, to Aether............     $              $                 $
     Proceeds, before expenses, to the selling
       stockholders..................................     $              $                 $
</TABLE>

     The expenses of the offering, not including the underwriting discount, are
estimated at $1.3 million and are payable by Aether.

OVER-ALLOTMENT OPTION

     We and the selling stockholders have granted options to the U.S.
underwriters to purchase up to 382,500 additional shares at the public offering
price less the underwriting discount. The U.S. underwriters may exercise these
options for 30 days from the date of this prospectus solely to cover any
over-allotments. If the U.S. underwriters exercise these options, each will be
obligated, subject to conditions contained in the U.S. purchase agreement, to
purchase a number of additional shares proportionate to that U.S. underwriter's
initial amount reflected in the above table.

     We and the selling stockholders have also granted options to the
international managers, exercisable for 30 days from the date of this prospectus
to purchase up to 67,500 additional shares to cover any over-allotments on terms
similar to those granted to the U.S. underwriters.

INTERSYNDICATE AGREEMENT

     The U.S. underwriters and the international managers have entered into an
intersyndicate agreement that provides for the coordination of their activities.
Under the intersyndicate agreement, the U.S. underwriters and the international
managers may sell shares to each other for purposes of resale at the initial
public offering price, less an amount not greater than the selling concession.
Under the intersyndicate agreement, the U.S. underwriters and any dealer to whom
they sell shares will not offer to sell or sell shares to persons who are
non-U.S. or non-Canadian persons or to persons they believe intend to resell to
persons who are non-U.S. or non-Canadian persons, except in the case of
transactions under the intersyndicate agreement. Similarly, the international
managers and any dealer to whom they sell shares will not offer to sell or sell
shares to U.S. persons or Canadian persons or to persons they believe intend to
resell to U.S. or Canadian persons, except in the case of transactions under the
intersyndicate agreement.

NO SALES OF SIMILAR SECURITIES

     We and the selling stockholders and our executive officers and directors
have agreed, with exceptions, not to sell or transfer any common stock for 90
days after the date of this prospectus without first obtaining the written
consent of Merrill Lynch. Specifically, we and these other individuals have
agreed not to directly or indirectly

     - offer, pledge, sell or contract to sell any common stock,

                                       85
<PAGE>   88

     - sell any option or contract to purchase any common stock,

     - purchase any option or contract to sell any common stock,

     - grant any option, right or warrant for the sale of any common stock,

     - lend or otherwise dispose of or transfer any common stock,

     - request or demand that we file a registration statement related to the
       common stock, or

     - enter into any swap or other agreement that transfers, in whole or in
       part, the economic consequence of ownership of any common stock whether
       any such swap or transaction is to be settled by delivery of shares or
       other securities, in cash or otherwise.

     This lockup provision applies to common stock and to securities convertible
into or exchangeable or exercisable for or repayable with common stock. It also
applies to common stock owned now or acquired later by the person executing the
agreement or for which the person executing the agreement later acquires the
power of disposition.

QUOTATION ON THE NASDAQ NATIONAL MARKET

     The shares are quoted on the Nasdaq National Market under the symbol
"AETH."

PRICE STABILIZATION, SHORT POSITIONS AND PENALTY BIDS

     Until the distribution of the shares is completed, SEC rules may limit
underwriters and selling group members from bidding for and purchasing our
common stock. However, the U.S. representatives may engage in transactions that
stabilize the price of the common stock, such as bids or purchases to peg, fix
or maintain that price.

     If the underwriters create a short position in the common stock in
connection with the offering, i.e., if they sell more shares than are listed on
the cover of this prospectus, the U.S. representatives may reduce that short
position by purchasing shares in the open market. The U.S. representatives may
also elect to reduce any short position by exercising all or part of the
over-allotment option described above. Purchases of the common stock to
stabilize its price or to reduce a short position may cause the price of the
common stock to be higher than it might be in the absence of such purchases.

     Neither we nor any of the underwriters makes any representation or
prediction as to the direction or magnitude of any effect that the transactions
described above may have on the price of the common stock. In addition, neither
we nor any of the underwriters makes any representation that the U.S.
representatives or the lead managers will engage in these transactions or that
these transactions, once commenced, will not be discontinued without notice.

PASSIVE MARKET MAKING

     In connection with this offering, underwriters and selling group members
may engage in passive market making transactions in the common stock on the
Nasdaq National Market in accordance with Rule 103 of Regulation M under the
Exchange Act during a period before the commencement of offers or sales of
common stock and extending through the completion of distribution. A passive
market maker must display its bid at a price not in excess of the highest
independent bid of that security. However, if all independent bids are lowered
below the passive market maker's bid, that bid must then be lowered when
specified purchase limits are exceeded.

OTHER RELATIONSHIPS

     Some of the underwriters and their affiliates have engaged in, and may in
the future engage in, investment banking and other commercial dealings in the
ordinary course of business with us. They have received and may receive
customary fees and commissions for these transactions.

                                       86
<PAGE>   89

                                 LEGAL MATTERS

     The validity of the common stock offered hereby will be passed upon for
Aether by Wilmer, Cutler & Pickering, Washington, D.C. George P. Stamas, a
consultant to Wilmer, Cutler & Pickering, is a director of Aether. Mr. Stamas
owns options to purchase 11,250 shares of common stock, and he holds a non-
voting interest in Telcom-ATI Investors, which owns 7,026,948 shares of common
stock. Certain legal matters in connection with this offering will be passed
upon for the underwriters by Hogan & Hartson L.L.P., Washington, D.C.

                                    EXPERTS

     The consolidated financial statements and schedule of Aether Systems, Inc.
as of December 31, 1998 and 1999, and for each of the years in the three-year
period ended December 31, 1999 have been included herein and in the registration
statement in reliance upon the reports of KPMG LLP, independent certified public
accountants, appearing elsewhere herein, and upon the authority of said firm as
experts in accounting and auditing.

     The financial statements of Mobeo, Inc. as of December 31, 1997 and 1998
and for each of the three years in the period ended December 31, 1998 included
in this prospectus have been included in reliance on the report of
PricewaterhouseCoopers LLP, independent accountants, given on the authority of
said firm as experts in auditing and accounting.

     The financial statements of Riverbed Technologies, Inc. as of December 31,
1998 and 1999, and for the period from October 21, 1998 (date of inception) to
December 31, 1998 and for the year ended December 31, 1999, have been included
herein and in the registration statement in reliance upon the report of KPMG
LLP, independent certified public accountants, appearing elsewhere herein, and
upon authority of said firm as experts in accounting and auditing.

                      WHERE YOU CAN FIND MORE INFORMATION

     We are subject to the informational requirements of the Securities Exchange
Act and we file reports, proxy and information statements and other information
with the Commission. You may read and copy all or any portion of the reports,
proxy and information statements or other information we file at the
Commission's principal office in Washington, D.C., and copies of all or any part
thereof may be obtained from the Public Reference Section of the Commission, 450
Fifth Street, N.W., Washington, D.C. 20549, and at the Commission's regional
offices located at Citicorp Center, 500 West Madison Street, Suite 1400,
Chicago, Illinois 60661 and at 7 World Trade Center, 13th Floor, New York, New
York 10048 after payment of fees prescribed by the Commission. Please call the
Commission at 1-800-SEC-0330 for further information on operation of the public
reference rooms. The Commission also maintains a World Wide Web site which
provides online access to reports, proxy and information statements and other
information regarding registrants that file electronically with the Commission
at the address http://www.sec.gov.

     We have filed with the Commission a Registration Statement on Form S-1
under the Securities Act with respect to the common stock to be sold in this
offering. This prospectus does not contain all of the information set forth in
the registration statement and the exhibits to the registration statement. For
further information with respect to Aether Systems, Inc. and our common stock
offered hereby, reference is made to the Registration Statement and the exhibits
filed as a part of the Registration Statement. Statements contained in this
prospectus concerning the contents of any contract or any other document are not
necessarily complete; reference is made in each instance to the copy of such
contract or any other document filed as an exhibit to the registration
statement. Each such statement is qualified in all respects by such reference to
such exhibit. The registration statement, including exhibits thereto, may be
inspected without charge at the locations described above, or obtained upon
payment of fees prescribed by the Commission.

                                       87
<PAGE>   90

                         INDEX TO FINANCIAL STATEMENTS

                              AETHER SYSTEMS, INC.

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Independent Auditors' Report................................   F-2
Consolidated Balance Sheets as of December 31, 1998 and
  1999......................................................   F-3
Consolidated Statements of Operations and Other
  Comprehensive Loss for the years ended December 31, 1997,
  1998 and 1999.............................................   F-4
Consolidated Statements of Stockholders' Equity for the
  years ended December 31, 1997, 1998 and 1999..............   F-5
Consolidated Statements of Cash Flows for the years ended
  December 31, 1997, 1998 and 1999..........................   F-6
Notes to Consolidated Financial Statements..................   F-7
</TABLE>

                                  MOBEO, INC.

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Report of Independent Accountants...........................  F-20
Balance Sheets as of December 31, 1997 and 1998.............  F-21
Statements of Operations for the years ended December 31,
  1996, 1997 and 1998.......................................  F-22
Statements of Changes in Stockholders' Equity (Deficit) for
  the years ended December 31, 1996, 1997 and 1998..........  F-23
Statements of Cash Flows for the years ended December 31,
  1996, 1997 and 1998.......................................  F-24
Notes to Financial Statements...............................  F-25
</TABLE>

                          RIVERBED TECHNOLOGIES, INC.

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Independent Auditors' Report................................  F-31
Balance Sheets as of December 31, 1998 and 1999.............  F-32
Statements of Operations for the period from October 21,
  1998 (Date of Inception) to December 31, 1998 and for the
  year ended December 31, 1999..............................  F-33
Statements of Stockholders' Equity (Deficit) for the period
  from October 21, 1998 (Date of Inception) to December 31,
  1998 and for the year ended December 31, 1999.............  F-34
Statements of Cash Flows for the period from October 21,
  1998 (Date of Inception) to December 31, 1998 and for the
  year ended December 31, 1999..............................  F-35
Notes to Financial Statements...............................  F-36
</TABLE>

                         UNAUDITED PRO FORMA CONDENSED
                       CONSOLIDATED FINANCIAL INFORMATION

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Description of Unaudited Pro Forma Condensed Consolidated
  Financial Information.....................................  F-44
Unaudited Pro Forma Condensed Consolidated Balance Sheet as
  of December 31, 1999......................................  F-45
Unaudited Pro Forma Condensed Consolidated Balance Sheet
  Adjustments for Completed Transactions as of December 31,
  1999......................................................  F-47
Unaudited Pro Forma Condensed Consolidated Balance Sheet
  Adjustments for Pending Transaction as of December 31,
  1999......................................................  F-49
Unaudited Pro Forma Condensed Consolidated Statement of
  Operations for the year ended
  December 31, 1999.........................................  F-51
Unaudited Pro Forma Condensed Consolidated Statement of
  Operations Adjustments for Completed Transactions for the
  year December 31, 1999....................................  F-53
Unaudited Pro Forma Condensed Consolidated Statement of
  Operations Adjustments for Pending Transaction for the
  year December 31, 1999....................................  F-55
</TABLE>

                                       F-1
<PAGE>   91

                          INDEPENDENT AUDITORS' REPORT

The Board of Directors and Stockholders
Aether Systems, Inc.:

     We have audited the accompanying consolidated balance sheets of Aether
Systems, Inc. and subsidiary as of December 31, 1998 and 1999, and the related
consolidated statements of operations and other comprehensive loss,
stockholders' equity and cash flows for each of the years in the three-year
period ended December 31, 1999. These consolidated financial statements are the
responsibility of the Company's management. Our responsibility is to express an
opinion on these consolidated financial statements based on our audits.

     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

     In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the financial position of Aether
Systems, Inc. and subsidiary as of December 31, 1998 and 1999, and the results
of their operations and their cash flows for each of the years in the three-year
period ended December 31, 1999, in conformity with generally accepted accounting
principles.

                                          KPMG LLP

McLean, Virginia
February 9, 2000

                                       F-2
<PAGE>   92

                              AETHER SYSTEMS, INC.

                          CONSOLIDATED BALANCE SHEETS

                                     ASSETS

<TABLE>
<CAPTION>
                                                                    DECEMBER 31,
                                                              -------------------------
                                                                 1998          1999
                                                              ----------   ------------
<S>                                                           <C>          <C>
Current assets:
  Cash and cash equivalents.................................  $1,755,350   $ 78,541,792
  Short-term investments....................................   6,191,287      2,091,962
  Trade accounts receivable, net of allowance for doubtful
     accounts of $157,061 and $56,371 at December 31, 1998
     and 1999, respectively.................................     118,489      1,002,845
  Inventory, net of allowance for obsolescence of $169,630
     and $115,153 at December 31, 1998 and 1999,
     respectively...........................................     143,617        688,494
  Prepaid expenses and other current assets.................      45,646      4,994,965
                                                              ----------   ------------
          Total current assets..............................   8,254,389     87,320,058
Property and equipment, net.................................     510,437      2,795,920
Intangible assets, net......................................          --     12,209,442
Other assets................................................          --        208,698
                                                              ----------   ------------
                                                              $8,764,826   $102,534,118
                                                              ==========   ============

                LIABILITIES, MEMBERS' CAPITAL AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable..........................................  $  195,930   $  1,425,435
  Accrued expenses..........................................     288,350      1,619,947
  Accrued employee compensation and benefits................     250,975        971,110
  Deferred revenue..........................................          --        175,193
                                                              ----------   ------------
          Total current liabilities.........................     735,255      4,191,685
Members' capital............................................   8,029,571             --
Stockholders' equity:
  Preferred stock, $0.01 par value; 1,000,000 shares
     authorized; 0 shares issued and outstanding at December
     31, 1999,..............................................          --             --
  Common stock, $0.01 par value; 75,000,000 shares
     authorized; 27,154,398 issued and outstanding at
     December 31, 1999......................................          --        271,543
  Additional paid-in-capital................................          --    120,892,478
  Accumulated deficit.......................................          --    (22,613,640)
  Notes receivable from stockholder.........................          --       (137,879)
  Unrealized loss on investments available for sale.........          --        (70,069)
                                                              ----------   ------------
          Total stockholders' equity........................          --     98,342,433
                                                              ----------   ------------
          Commitments and contingencies
                                                              $8,764,826   $102,534,118
                                                              ==========   ============
</TABLE>

          See accompanying notes to consolidated financial statements.

                                       F-3
<PAGE>   93

                              AETHER SYSTEMS, INC.

       CONSOLIDATED STATEMENTS OF OPERATIONS AND OTHER COMPREHENSIVE LOSS

<TABLE>
<CAPTION>
                                                               YEAR ENDED DECEMBER 31,
                                                       ----------------------------------------
                                                          1997          1998           1999
                                                       -----------   -----------   ------------
<S>                                                    <C>           <C>           <C>
Subscriber revenue...................................  $   161,400   $   549,057   $  3,731,792
Engineering services revenue.........................    1,624,733       963,165      2,594,476
                                                       -----------   -----------   ------------
          Total revenue..............................    1,786,133     1,512,222      6,326,268
Cost of subscriber revenue...........................      447,480       797,165      2,109,807
Cost of engineering services revenue.................      846,140       304,137      1,366,426
                                                       -----------   -----------   ------------
          Total cost of revenue......................    1,293,620     1,101,302      3,476,233
                                                       -----------   -----------   ------------
          Gross profit...............................      492,513       410,920      2,850,035
                                                       -----------   -----------   ------------
Operating expenses:
  Research and development (exclusive of option and
     warrant expense of $0, $0, and $150,288 for the
     year ended December 31, 1997, 1998 and 1999,
     respectively)...................................      733,630     1,267,320      2,613,726
  General and administrative (exclusive of option and
     warrant expense of $40,277, $32,580, and
     $18,004,623 for the years ended December 31,
     1997, 1998, and 1999, respectively).............    1,504,250     2,773,332      5,891,504
  Selling and marketing (exclusive of option and
     warrant expense of $0, $0 and $1,043,298 for the
     years ended December 31, 1997, 1998, and 1999,
     respectively)...................................      333,191       840,455      2,095,074
  Depreciation and amortization......................      189,160       264,685      1,089,013
  Option and warrant expense.........................       40,277        32,580     19,198,209
                                                       -----------   -----------   ------------
                                                         2,800,508     5,178,372     30,887,526
                                                       -----------   -----------   ------------
          Operating loss.............................   (2,307,995)   (4,767,452)   (28,037,491)
Other income (expense):
  Interest income....................................        7,788       140,479        996,436
  Interest expense...................................           --       (70,171)    (1,056,718)
  Equity in losses of investments....................     (144,825)                  (2,425,000)
  Realized gain (loss) on sale of short-term
     investments.....................................           --         3,872       (168,721)
  Realized loss on sale of investment................     (302,145)           --             --
                                                       -----------   -----------   ------------
          Net loss...................................  $(2,747,177)  $(4,693,272)  $(30,691,494)
Other comprehensive loss-unrealized holding gain
  (loss) on investments available for sale...........           --       (58,030)       (12,039)
                                                       -----------   -----------   ------------
Comprehensive loss...................................  $(2,747,177)  $(4,751,302)  $(30,703,533)
                                                       ===========   ===========   ============
Pro forma statement of operations data (unaudited):
  Loss before income taxes, as reported..............  $(2,747,177)  $(4,693,272)  $(30,691,494)
  Pro forma income tax provision (benefit)...........           --            --             --
                                                       -----------   -----------   ------------
  Pro forma net loss.................................  $(2,747,177)  $(4,693,272)  $(30,691,494)
                                                       ===========   ===========   ============
  Pro forma net loss per share-basic and diluted.....  $     (0.22)  $     (0.29)  $      (1.45)
                                                       ===========   ===========   ============
  Pro forma weighted average shares outstanding-basic
     and diluted.....................................   12,655,901    15,916,383     21,207,225
                                                       ===========   ===========   ============
</TABLE>

          See accompanying notes to consolidated financial statements.

                                       F-4
<PAGE>   94

                              AETHER SYSTEMS, INC.

                CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
<TABLE>
<CAPTION>
                                                                                            NOTES
                                                            ADDITIONAL                   RECEIVABLE    UNREALIZED
                                    PREFERRED    COMMON      PAID-IN      ACCUMULATED       FROM         LOSS ON      MEMBERS'
                                      STOCK      STOCK       CAPITAL        DEFICIT      STOCKHOLDER   INVESTMENTS     CAPITAL
                                    ---------   --------   ------------   ------------   -----------   -----------   -----------
<S>                                 <C>         <C>        <C>            <C>            <C>           <C>           <C>
Balance at January 1, 1997........     $--      $     --   $         --   $         --    $      --     $     --     $ 1,100,866
 Issuance of member units in
   February 1997..................      --            --             --             --           --           --       1,000,000
 Issuance of member units in
   December 1997..................      --            --             --             --           --           --         690,369
 Unit option and warrant
   expense........................      --            --             --             --           --           --          40,277
 Note receivable from member......      --            --             --             --           --           --         (10,000)
 Net loss.........................      --            --             --             --           --           --      (2,747,177)
                                       ---      --------   ------------   ------------    ---------     --------     -----------
Balance at December 31, 1997......      --            --             --             --           --           --          74,335
 Issuance of member units in
   January 1998...................      --            --             --             --           --           --       1,499,314
 Issuance of warrants in
   June 1998......................      --            --             --             --           --           --          50,000
 Exercise of warrants in August
   1998...........................      --            --             --             --           --           --              56
 Conversion of note payable and
   issuance of member units in
   August 1998....................      --            --             --             --           --           --         252,467
 Issuance of member units in
   August 1998....................      --            --             --             --           --           --       5,000,000
 Issuance of member units in
   October 1998...................      --            --             --             --           --           --       6,000,000
 Unit option and warrant
   expense........................      --            --             --             --           --           --          32,580
 Unrealized loss on investments
   available for sale.............      --            --             --             --           --                      (58,030)
 Note receivable from member......      --            --             --             --           --           --        (127,879)
 Net loss.........................      --            --             --             --           --           --      (4,693,272)
                                       ---      --------   ------------   ------------    ---------     --------     -----------
Balance at December 31, 1998......      --            --             --             --           --                    8,029,571
 Issuance of replacement options
   to Mobeo, Inc. employees.......      --            --             --             --           --           --         374,000
 Exercise of unit options and
   warrants.......................      --            --             --             --           --           --          70,000
 Option and warrant expense.......      --            --             --             --           --           --       2,323,698
 Net loss -- pre merger...........      --            --             --             --           --           --      (8,077,854)
 Merger of Aether Technologies
   International, L.L.C. into
   Aether Systems, Inc. in October
   1999...........................      --       200,670      2,714,654             --     (137,879)     (58,030)     (2,719,415)
 Net proceeds of initial public
   offering.......................      --        69,000    101,044,831             --           --           --
 Unrealized loss on investments
   available for sale.............      --            --             --             --           --      (12,039)             --
 Option and warrant expense.......      --            --     16,874,511             --           --           --              --
 Exercise of stock options........      --         1,873        258,482             --           --           --              --
 Net loss -- post merger..........      --            --             --    (22,613,640)          --           --              --
                                       ---      --------   ------------   ------------    ---------     --------     -----------
Balance at December 31, 1999......     $--      $271,543   $120,892,478   $(22,613,640)   $(137,879)    $(70,069)    $        --
                                       ===      ========   ============   ============    =========     ========     ===========

<CAPTION>

                                       TOTAL
                                    ------------
<S>                                 <C>
Balance at January 1, 1997........  $  1,100,866
 Issuance of member units in
   February 1997..................     1,000,000
 Issuance of member units in
   December 1997..................       690,369
 Unit option and warrant
   expense........................        40,277
 Note receivable from member......       (10,000)
 Net loss.........................    (2,747,177)
                                    ------------
Balance at December 31, 1997......        74,335
 Issuance of member units in
   January 1998...................     1,499,314
 Issuance of warrants in
   June 1998......................        50,000
 Exercise of warrants in August
   1998...........................            56
 Conversion of note payable and
   issuance of member units in
   August 1998....................       252,467
 Issuance of member units in
   August 1998....................     5,000,000
 Issuance of member units in
   October 1998...................     6,000,000
 Unit option and warrant
   expense........................        32,580
 Unrealized loss on investments
   available for sale.............       (58,030)
 Note receivable from member......      (127,879)
 Net loss.........................    (4,693,272)
                                    ------------
Balance at December 31, 1998......     8,029,571
 Issuance of replacement options
   to Mobeo, Inc. employees.......       374,000
 Exercise of unit options and
   warrants.......................        70,000
 Option and warrant expense.......     2,323,698
 Net loss -- pre merger...........    (8,077,854)
 Merger of Aether Technologies
   International, L.L.C. into
   Aether Systems, Inc. in October
   1999...........................            --
 Net proceeds of initial public
   offering.......................   101,113,831
 Unrealized loss on investments
   available for sale.............       (12,039)
 Option and warrant expense.......    16,874,511
 Exercise of stock options........       260,355
 Net loss -- post merger..........   (22,613,640)
                                    ------------
Balance at December 31, 1999......  $ 98,342,433
                                    ============
</TABLE>

          See accompanying notes to consolidated financial statements.

                                       F-5
<PAGE>   95

                              AETHER SYSTEMS, INC.

                     CONSOLIDATED STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                                      YEAR ENDED DECEMBER 31,
                                                              ----------------------------------------
                                                                 1997          1998           1999
                                                              -----------   -----------   ------------
<S>                                                           <C>           <C>           <C>
Cash flows from operating activities:
  Net loss..................................................  $(2,747,177)  $(4,693,272)  $(30,691,494)
  Adjustments to reconcile net loss to net cash used by
    operating activities:
    Depreciation and amortization...........................      189,160       264,685      1,089,013
    Provision (recovery) for doubtful accounts..............           --       157,061        (59,530)
    Provision (recovery) for inventory obsolescence.........           --       169,630        (54,477)
    Realized (gain) loss on sale of short-term
     investments............................................           --        (3,872)       168,721
    Equity in losses of investments.........................      144,825            --      2,425,000
    Realized loss on sale of investment.....................      302,145            --             --
    Issuance of warrants....................................           --        50,000             --
    Option and warrant expense..............................       40,277        32,580     19,198,209
    Changes in assets and liabilities:
      (Increase) decrease in trade accounts receivable......       74,812      (153,417)    (1,730,942)
      Increase in inventory.................................           --      (313,247)      (490,400)
      (Increase) decrease in prepaid expenses and other
       current assets.......................................        3,828       (30,529)    (3,785,442)
      Increase (decrease) in accounts payable...............       67,360        83,421       (376,810)
      Increase in accrued expenses and employee compensation
       and benefits.........................................      272,622       216,457      2,051,732
      Increase (decrease) in deferred revenue...............      162,500      (162,500)       175,193
                                                              -----------   -----------   ------------
         Net cash used by operating activities..............   (1,489,648)   (4,383,003)   (12,081,227)
                                                              -----------   -----------   ------------
Cash flows (used) by investing activities:
  Sales of short-term investments...........................       49,977     1,295,525     12,640,562
  Purchases of short-term investments.......................           --    (7,535,118)    (8,721,997)
  Acquisition of Mobeo, Inc., net of cash acquired..........           --            --    (11,547,976)
  Purchases of property and equipment.......................     (441,700)     (228,274)    (2,447,106)
  Investment in OmniSky, Inc................................           --            --     (2,500,000)
  Long-term investments.....................................      (23,000)           --             --
  Proceeds from sale of investment in joint venture.........      205,000            --             --
                                                              -----------   -----------   ------------
         Net cash used in investing activities..............     (209,723)   (6,467,867)   (12,576,517)
                                                              -----------   -----------   ------------
Cash flows provided by financing activities:
  Issuance of member units..................................    1,690,369    12,501,781             --
  Proceeds from issuance of common stock....................           --            --    101,113,831
  Repayments from member....................................      (50,000)           --             --
  Proceeds from note payable................................      150,000       500,000             --
  Repayments on notes payable...............................           --      (400,000)            --
  Proceeds from credit facility.............................           --            --     14,830,000
  Repayments of credit facility.............................           --            --    (14,830,000)
  Issuance of notes receivable from member..................      (10,000)     (127,879)            --
  Exercise of options and warrants..........................           --            56        330,355
                                                              -----------   -----------   ------------
         Net cash provided by financing activities..........    1,780,369    12,473,958    101,444,186
                                                              -----------   -----------   ------------
         Net increase in cash and cash equivalents..........       80,998     1,623,088     76,786,442
Cash and cash equivalents, at beginning of period...........       51,264       132,262      1,755,350
                                                              -----------   -----------   ------------
Cash and cash equivalents, at end of period.................  $   132,262   $ 1,755,350   $ 78,541,792
                                                              ===========   ===========   ============
Supplemental disclosure of cash flow information:
  Cash paid during the year for interest....................  $     3,894   $    20,171   $  1,026,643
                                                              ===========   ===========   ============
</TABLE>

- ---------------
Supplemental disclosure of noncash investing and financing activities:
    In 1997, the Company made a $26,457 investment in Navox, Inc. by forgiving a
     trade account receivable of an equal amount.
    In 1998, a member converted a $250,000 promissory note payable into
     membership units.
    In 1998 and 1999, the Company incurred unrealized holding losses associated
     with its investments available for sale totaling $58,030 and $12,039. These
     amounts have been reported as reductions in members' capital and
     stockholders' equity, respectively.
    In September 1999, the Company issued 18,442 unit options (46,105 shares)
     valued at $374,000 as part of the cost to acquire Mobeo, Inc. This amount
     has been reported as an increase in members' capital.
    In October 1999, approximately $1.1 million of trade receivables owed to the
     Company by OmniSky, Inc. were settled against amounts due in connection
     with the purchase of 20,000 modems from OmniSky, Inc.

          See accompanying notes to consolidated financial statements.

                                       F-6
<PAGE>   96

                              AETHER SYSTEMS, INC.

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
(1)  ORGANIZATION AND DESCRIPTION OF BUSINESS

     Aether Systems, Inc. and its subsidiary (the "Company") designs, develops,
sells and supports wireless data services and systems enabling people to use
handheld devices for mobile data communications and real-time transactions. The
Company operates in a highly competitive environment subject to rapid
technological change and emergence of new technology. Although management
believes its services are transferable to emerging technologies, rapid changes
in technology could have an adverse financial impact on the Company.

     The Company expects to expand its operations through continued capital
investment in new systems and services and through strategic acquisitions. The
Company has a limited operating history and has incurred net losses since its
inception. The Company expects to continue to incur significant sales and
marketing, systems development and administrative expenses. The Company may
require additional capital in the future to meet its operating and capital
needs.

(2)  MERGER AND INITIAL PUBLIC OFFERING

     The Company is the successor to the business formerly conducted by Aether
Systems, L.L.C. ("Aether") (previously Aether Technologies International,
L.L.C.), which was formed in January, 1996. Effective October 26, 1999, in
connection with the Company's initial public offering of common stock, Aether
merged with and into Aether Systems, Inc. The Company is the surviving company
in the merger, and owns all of the assets and rights and is subject to all of
the obligations and liabilities of Aether. Immediately prior to the merger, each
member of the Company contributed its membership units in Aether Systems, L.L.C.
to Aether Systems, Inc., a newly formed Delaware corporation, in exchange for
two and one-half shares of common stock of Aether Systems, Inc. Effective with
the merger, the Company converted to a Subchapter C Corporation under the
Internal Revenue Code of 1986 as amended.

     On October 26, 1999, the Company completed its initial public offering,
which involved the sale of 6,900,000 shares of common stock at $16.00 per share,
including 900,000 shares from the exercise of the underwriters' over-allotment
option, at the initial public offering price less underwriting discounts and
offering expenses. Net proceeds to the Company after deducting underwriting
discounts, commissions and other expenses of the offering were approximately
$101.1 million.

(3)  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

  (a) Principles of Consolidation

     The consolidated financial statements include the accounts of Aether
Systems, Inc. and its wholly owned subsidiary, Mobeo, Inc. All significant
intercompany transactions and balances have been eliminated in consolidation.

  (b) Revenue Recognition

     The Company derives subscriber revenue from the provision of real-time
access to information from selected financial markets integrated into existing
wireless communication platforms. Subscriber revenue consists of monthly fixed
charges for usage and equipment and is recognized as the service is provided on
a monthly basis and a one time non-refundable activation fee which is recognized
upon service activation. Direct activation costs are expensed as incurred.
Certain of the Company's customers are billed in advance with revenue deferred
and recognized on a monthly basis over the term of the agreement. Also included
in subscriber revenue are market exchange fees for access to financial
information from the securities exchanges and markets, which are recognized as
the service is provided. Engineering services revenue is derived from the
provision of wireless integration consulting under time-and-materials and
fixed-fee contracts. Revenue on time-and-materials contracts is recognized as
services are performed. Revenue on fixed-fee contracts is recognized on the
percentage-of-completion method based on costs incurred in

                                       F-7
<PAGE>   97
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

relation to total estimated costs. Anticipated contract losses are recognized as
soon as they become known and estimable.

  (c) Cost of Revenues

     Cost of subscriber revenue consists primarily of airtime costs, financial
data costs, wireless handheld device costs, and securities exchange and market
fees. Since the Company's service agreements are generally for a one-year period
and subject to cancellation, non-payment and non-return risk, the Company
expenses the cost of wireless handheld devices upon shipment to the customer.
Cost of engineering services revenue consists of cash compensation and related
costs for engineering personnel and materials.

  (d) Cash and Cash Equivalents

     Cash equivalents include all highly liquid investments purchased with
original maturities of three months or less. Cash equivalents consist of
approximately $193,000 and $5,521,000 in overnight repurchase agreements,
$1,562,000 and $68,831,000 in money market accounts, and $0 and $3,979,000 in
commercial paper at December 31, 1998 and 1999, respectively.

  (e) Short-term Investments

     Short-term investments consist of highly liquid investments with original
maturities greater than three months and less than one year and those
longer-term investments that the Company expects to liquidate within twelve
months. The Company has classified its short-term investments as "available for
sale" and carries such investments at fair value. Unrealized gains (losses) are
excluded from earnings and are reported as a separate component of other
comprehensive income until realized. Realized gains and losses from the sale of
these investments are determined on a specific identification basis.

  (f) Fair Value of Financial Instruments

     The carrying amounts of the Company's financial instruments, which include
cash equivalents, accounts receivable, accounts payable and accrued expenses
approximate their fair values due to the relatively short duration of the
instruments.

  (g) Concentration of Credit Risk

     Financial instruments that potentially subject the Company to a
concentration of credit risk consist of accounts receivable. The Company extends
credit to its customers on an unsecured basis in the normal course of business.

  (h) Inventory

     Inventory, net of allowance for obsolete and slow-moving inventory,
consists primarily of handheld and laptop computers, pagers, wireless modems,
and accessories and is stated at the lower of cost or market. Cost is determined
using the first-in, first-out (FIFO) method. The inventory of the Company is
subject to rapid technological changes which could have an adverse impact on its
realization in future periods. In addition, there are a limited number of
suppliers of the Company's inventory.

  (i) Property and Equipment

     Property and equipment are stated at cost. Depreciation is calculated using
the straight-line method over the estimated useful lives of the assets, which
range from three to seven years. The costs of leasehold improvements are
capitalized and amortized using the straight-line method over the shorter of the
lease term or the estimated useful life of the asset.

                                       F-8
<PAGE>   98
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

  (j) Investment in OmniSky, Inc.

     The Company uses the equity method of accounting for advances to and
earnings and losses of its investment in OmniSky, Inc.

  (k) Goodwill and Recovery of Long-Lived Assets

     Cost in excess of the fair value of tangible and identifiable intangible
net assets acquired is included in intangible assets and is amortized on a
straight-line basis over seven years.

     The Company's policy is to review its long-lived assets for impairment
whenever events or changes in circumstances indicate that the carrying amount
may not be recoverable. The Company recognizes an impairment loss when the sum
of the expected future undiscounted cash flows is less than the carrying amount
of the asset. The measurement of the impairment losses to be recognized is based
upon the difference between the fair value and the carrying amount of the
assets.

  (l) Stock Options and Warrants

     The Company accounts for equity-based compensation arrangements in
accordance with the provisions of Accounting Principle Board ("APB") Opinion No.
25, "Accounting for Stock Issued to Employees," and related interpretations, and
complies with the disclosure provisions of Statement of Financial Accounting
Standards ("SFAS") No. 123, "Accounting for Stock-Based Compensation." Under APB
No. 25, compensation expense is based upon the difference, if any, on the date
of grant, between the fair value of the Company's stock and the exercise price.
All equity-based awards to non-employees are accounted for at their fair value
in accordance with SFAS No. 123.

  (m) Pro Forma Income (Loss) Data (Unaudited)

     The accompanying unaudited pro forma information has been prepared as if
the Company was treated as Subchapter C Corporation for Federal and state income
tax purposes from January 1, 1997. The Company has provided no income taxes on a
pro forma basis due to the losses incurred in all periods.

     The Company computes net income (loss) per share in accordance with SFAS
No. 128, "Earnings Per Share," and SEC Staff Accounting Bulletin No. 98 ("SAB
98"). Under the provisions of SFAS No. 128 and SAB 98, basic net income (loss)
per share is computed by the dividing the net income (loss) available to common
stockholders for the period by the weighted average number of common shares
outstanding during the period. Diluted net income (loss) per share is computed
by dividing the net income (loss) for the period by the weighted average number
of common and dilutive common equivalent shares outstanding during the period.
Pro forma basic and diluted net loss per share has been calculated assuming that
the capital structure established at the date of the initial public offering was
in effect during the periods presented. As the Company had a net loss in each of
the periods presented, pro forma basic and diluted net loss per share are the
same.

  (n) Research and Development

     Research and development costs are expensed as incurred.

  (o) Advertising Expense

     Advertising costs are expensed as incurred. Advertising expense was
approximately $248,000, $504,000, and $933,000 for the years ended December 31,
1997, 1998 and 1999, respectively.

  (p) Income Taxes

     The Company recognizes income taxes using the asset and liability method,
in accordance with Statement of Financial Accounting Standards ("SFAS") No. 109.
Under the asset and liability method, deferred tax assets and liabilities are
recognized for the future tax consequences attributable to differences

                                       F-9
<PAGE>   99
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

between the financial statement carrying amounts of existing assets and
liabilities and their respective tax bases. Deferred tax assets and liabilities
are measured using enacted tax rates expected to apply to taxable income in the
years in which those temporary differences are expected to be recovered or
settled. The effect of a tax rate change on deferred tax assets and liabilities
is recognized in income in the period that includes the enactment date.

     Prior to October 26, 1999, Aether had elected limited liability status and,
as such, was not directly subject to Federal and state income taxes. Rather, the
members were responsible for income taxes on their proportionate share of
taxable income and entitled to their proportionate share of tax deductions and
tax credits.

  (q) Use of Estimates

     The preparation of consolidated financial statements in conformity with
generally accepted accounting principles requires management to make estimates
and assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the dates of the consolidated
financial statements and the reported amounts of revenue and expenses during the
reporting period. Actual results could differ from those estimates.

  (r) Other Comprehensive Loss

     Effective January 1, 1998, the Company adopted SFAS No. 130, "Reporting
Comprehensive Income", which established standards for reporting and displaying
comprehensive income and its components in financial statements. Comprehensive
income, as defined, includes changes in equity of a business enterprise during a
period from transactions and other events and circumstances from non-owner
sources. Other comprehensive income refers to revenue, expenses, gains and
losses that under generally accepted accounting principles are included in
comprehensive income, but excluded from net income.

     For the years ended December 31, 1998 and 1999, other comprehensive income
(loss) consists of unrealized losses on investments available for sale.

  (s) Recent Accounting Pronouncements

     In June 1998, the FASB issued SFAS No. 133, "Accounting for Derivative
Instruments and Hedging Activities." The new standard establishes accounting and
reporting standards for derivative instruments, including certain derivative
instruments embedded in other contracts and for hedging activities. This
statement, as amended, is effective for all fiscal quarters beginning after June
15, 2000. The Company does not expect SFAS No. 133 to have a material affect on
its financial position or results of operations.

(4)  ACQUISITION OF MOBEO, INC.

     On August 19, 1999, the Company entered into a purchase agreement to
acquire all the outstanding common stock of Mobeo, Inc. ("Mobeo") for an
aggregate purchase price consisting of cash of approximately $11.5 million,
including acquisition costs of approximately $112,000, and 18,442 unit options
(46,105 shares) with an exercise price of $12.00 per unit ($4.80 per share)
valued at approximately $374,000. The acquisition was completed on September 28,
1999. Mobeo provides employees and customers at major banks and financial
institutions with continuous pricing information and news headlines for foreign
exchange, government securities, and commodity markets on wireless handheld
devices. Additionally, the Company entered into two-year advisory service
agreements with two former owners of Mobeo which provided for the grant of an
aggregate 125,000 unit options (312,500 shares) with an exercise price of $15.00
per unit ($6.00 per share). The Company also issued 22,000 options (55,000
shares) at an exercise price of $6.00 per unit ($2.40 per share) and 30,000
options (75,000 shares) at an exercise price of $12.00 per unit ($4.80 per
share) to employees of Mobeo. The Company has recorded option and warrant
expense of approximately $418,000 in 1999 associated with

                                      F-10
<PAGE>   100
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

these options and expects to record an additional $2.9 million in option and
warrant expense over the remaining service and vesting periods.

     The acquisition has been accounted for under the purchase method of
accounting and, accordingly, the assets acquired and liabilities assumed have
been recorded at their estimated fair value as of the acquisition date. The
allocation of the purchase price is summarized as follows:

<TABLE>
<S>                                                           <C>
Current assets..............................................  $   258,000
Property and equipment......................................      372,000
Other assets................................................      133,000
Current liabilities.........................................   (1,606,000)
Goodwill and other intangibles..............................   12,765,000
                                                              -----------
Total consideration paid....................................  $11,922,000
                                                              ===========
</TABLE>

     The following summary, prepared on a pro forma basis, presents the results
of operations (unaudited) of the Company as if the Mobeo acquisition had been
completed as of January 1, 1998:

<TABLE>
<CAPTION>
                                                                    (UNAUDITED)
                                                       DECEMBER 31, 1998   DECEMBER 31, 1999
                                                       -----------------   -----------------
<S>                                                    <C>                 <C>
Revenue..............................................     $10,093,008        $ 13,836,410
Net loss.............................................      (6,842,574)        (31,749,078)
Net loss per share -- basic and diluted..............            (.43)              (1.50)
</TABLE>

     The unaudited pro forma results of operations are not necessarily
indicative of what actually would have occurred if Mobeo had been owned for the
entire periods presented or a projection of the Company's results of operations
for any future period.

(5)  INVESTMENT IN OMNISKY, INC.

     On August 9, 1999, the Company entered into a new venture with 3Com
Corporation ("3Com"), forming a new Company called OpenSky, which was later
renamed OmniSky, Inc. ("OmniSky"). OmniSky was formed to develop wireless
Internet access, e-mail and electronic commerce services that address
opportunities in the emerging consumer and business mass markets. The Company
contributed a perpetual, non-exclusive, non-assignable, worldwide license to
certain proprietary software in exchange for a 26% equity interest in OmniSky in
the form of 7,000,000 shares of Series A Preferred Stock and an option to
purchase an additional 3,000,000 shares of Series A Preferred Stock for an
additional $2.5 million. Upon exercising the option, the Company would increase
its ownership in OmniSky to 33% on a fully diluted basis. On November 9, 1999,
the Company exercised its option to acquire these additional shares. The chief
executive officer of the Company serves as a member of OmniSky's board of
directors. The Company provides engineering services to OmniSky under an
agreement in the amount of $3.0 million through June 2000. As of December 31,
1999, the Company has recognized $2.2 million in engineering services revenue
under the OmniSky agreement. This amount represents 86% of engineering services
revenue and 35% of total revenue for the year ended December 31, 1999. The
agreement also provides for OmniSky to pay $1.50 per month per subscriber for
the use of the Company's network operations center. The Company has the right to
offer OmniSky's services to its subscribers for a monthly fee of $3.00 per
subscriber. There has been no activity as of December 31, 1999 under these
provisions of the agreement.

     The Company accounts for its investment in OmniSky under the equity method
of accounting. The Company recorded $2.4 million in expenses through December
31, 1999, to reflect its proportionate share of the losses in OmniSky based upon
unaudited financial information provided by OmniSky.

                                      F-11
<PAGE>   101
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

     During 1999, OmniSky, Inc. reported a net loss of approximately $5.7
million (unaudited) and had net assets of $9.7 million (unaudited) as of
December 31, 1999.

     In October 1999, the Company agreed to purchase 25,000 Minstrel V modems
from OmniSky for $230 per modem. OmniSky has an exclusive buying arrangement
with Novatel for Minstrel V modems, which began in December 1999 and will run
through March of 2000. The Company purchased 20,000 of the 25,000 for cash of
$3.5 million and cancellation of $1.1 million of trade receivables owed to the
Company by Omnisky. An additional $1.2 million will be paid to OmniSky, Inc. for
the remaining 5,000 modems after the delivery of the initial 20,000 modems,
which began in November 1999 and will continue through April of 2000. As of
December 31, 1999, the Company has recorded prepaid expenses of approximately
$4.5 million associated with this agreement. The Company received approximately
$58,000 of modems during 1999.

     On January 18, 2000, the Company entered into a Series B Preferred Stock
Purchase Agreement, whereby the Company purchased 1,439,809 shares of Series B
preferred stock of OmniSky for an aggregate purchase price of approximately $6.7
million, consisting of cash of approximately $6.1 million and the cancellation
of approximately $600,000 of indebtedness owed to the Company by OmniSky for
engineering services. The investment was made to maintain the Company's 33
percent ownership in OmniSky. The Company's per share purchase price was the
same as the other Series B Preferred Stock investors.

(6)  SHORT-TERM INVESTMENTS

     As of December 31, 1998, short-term available for sale investments consists
of:

<TABLE>
<CAPTION>
                                                      GROSS           GROSS
                                     AMORTIZED     UNREALIZED       UNREALIZED        FAIR
                                        COST      HOLDING GAINS   HOLDING LOSSES     VALUE
                                     ----------   -------------   --------------   ----------
<S>                                  <C>          <C>             <C>              <C>
U.S. Treasury securities...........  $1,929,810      $    --         $(21,677)     $1,908,133
Corporate debt securities..........   4,319,507       11,881          (48,234)      4,283,154
                                     ----------      -------         --------      ----------
                                     $6,249,317      $11,881         $(69,911)     $6,191,287
                                     ==========      =======         ========      ==========
</TABLE>

     Maturities of debt securities classified as available for sale were as
follows at December 31, 1998:

<TABLE>
<CAPTION>
                                                              AMORTIZED       FAIR
                                                                 COST        VALUE
                                                              ----------   ----------
<S>                                                           <C>          <C>
Due within one year.........................................  $2,124,838   $2,129,084
Due after one year through five years.......................   1,184,890    1,157,964
Due after five years through ten years......................   1,435,695    1,412,043
Due after ten years.........................................   1,503,894    1,492,196
                                                              ----------   ----------
                                                              $6,249,317   $6,191,287
                                                              ==========   ==========
</TABLE>

     As of December 31, 1999, short-term available for sale investments consists
of:

<TABLE>
<CAPTION>
                                                      GROSS           GROSS
                                     AMORTIZED     UNREALIZED       UNREALIZED        FAIR
                                        COST      HOLDING GAINS   HOLDING LOSSES     VALUE
                                     ----------   -------------   --------------   ----------
<S>                                  <C>          <C>             <C>              <C>
U.S. Treasury securities...........  $1,828,460        $95           $(45,895)     $1,782,660
Corporate debt securities..........     333,571         --            (24,269)        309,302
                                     ----------        ---           --------      ----------
                                     $2,162,031        $95           $(70,164)     $2,091,962
                                     ==========        ===           ========      ==========
</TABLE>

                                      F-12
<PAGE>   102
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

     Maturities of debt securities classified as available for sale were as
follows at December 31, 1999:

<TABLE>
<CAPTION>
                                                              AMORTIZED       FAIR
                                                                 COST        VALUE
                                                              ----------   ----------
<S>                                                           <C>          <C>
Due within one year.........................................  $  325,076   $  326,177
Due after one year through five years.......................     855,751      834,434
Due after five years through ten years......................     717,944      667,257
Due after ten years.........................................     263,260      264,094
                                                              ----------   ----------
                                                              $2,162,031   $2,091,962
                                                              ==========   ==========
</TABLE>

(7)  PROPERTY AND EQUIPMENT

     Property and equipment consists of the following:

<TABLE>
<CAPTION>
                                                                       DECEMBER 31,
                                                   ESTIMATED     ------------------------
                                                  USEFUL LIVES      1998         1999
                                                  ------------   ----------   -----------
<S>                                               <C>            <C>          <C>
Furniture and fixtures..........................      7 Years    $  102,345   $   593,030
Computer and equipment..........................  3 - 5 Years       684,328     2,113,229
Software........................................      3 Years       175,000       175,000
Leasehold improvements..........................      5 Years        47,854       946,927
                                                  -----------    ----------   -----------
                                                                  1,009,527     3,828,186
Less depreciation and amortization..............                   (499,090)   (1,032,266)
                                                                 ----------   -----------
                                                                 $  510,437   $ 2,795,920
                                                                 ==========   ===========
</TABLE>

(8)  INTANGIBLE ASSETS

     Intangible assets consists of the following:

<TABLE>
<CAPTION>
                                                               ESTIMATED     DECEMBER 31,
                                                              USEFUL LIVES       1999
                                                              ------------   ------------
<S>                                                           <C>            <C>
Goodwill....................................................    7 Years      $  6,165,279
Acquired subscribers........................................    5 Years         6,400,000
Assembled workforce.........................................    3 Years           200,000
                                                                             ------------
                                                                               12,765,279
Less accumulated amortization...............................                     (555,837)
                                                                             ------------
                                                                             $ 12,209,442
                                                                             ============
</TABLE>

     Goodwill represents the purchase price in excess of the fair value of the
tangible and identifiable intangible assets acquired.

(9)  NOTES PAYABLE TO MEMBERS

     The Company had an unsecured note payable of $150,000 as of December 31,
1997 due to one of its members, Telcom Ventures LLC ("Telcom Ventures"). The
note carried interest at a rate of 7.5 percent per annum and all principal and
accrued interest was due in January 1999, or earlier upon the occurrence of
specified criteria. The note payable, plus accrued interest, was repaid in 1998.

     In June 1998, the Company borrowed $250,000 from one of its members,
Pyramid Ventures, Inc. ("Pyramid") under a convertible promissory note. The note
was unsecured, bore interest at 8 percent per annum, and was convertible into
membership units at the option of the member. In August 1998, the

                                      F-13
<PAGE>   103
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

member elected to convert the note and accrued interest of $2,467 into 57,180
membership units (142,950 shares) in accordance with its terms.

     In June 1998, the Company borrowed $250,000 from another one of its
members, Telcom Ventures, under a similar convertible promissory note. All
principal and accrued interest was paid by the Company in August 1998.

     In connection with the convertible promissory notes, the Company granted
warrants to purchase 5,656 member units (14,140 shares) at an exercise price of
$0.01 per unit to Pyramid and Telcom Ventures (note 13). The estimated value of
the warrants on the grant date of $50,000 was recognized in interest expense in
1998. Pyramid exercised its warrants to purchase 5,656 member units (14,140
shares) in August 1998. In August 1999, Telcom Ventures exercised its warrants
to purchase 5,656 member units (14,140 shares).

     All outstanding membership units were subsequently exchanged for common
stock in connection with the Company's initial public offering, effective
October 26, 1999 (Note 2).

(10)  INCOME TAXES

     Effective October 26, 1999, in connection with the Company's initial public
offering of common stock, Aether merged with and into the Company and the merged
entity became a Subchapter C Corporation under the Internal Revenue Code of
1986. As a result, the Company recorded a deferred tax expense of approximately
$1.4 million, principally relating to intangible assets other than goodwill
acquired as part of the Mobeo acquisition prior to becoming a Subchapter C
Corporation, offset, in part, by deferred tax assets associated with option and
warrant expense. The Company recorded a deferred tax benefit of $1.4 million
related to losses generated subsequent to the change in tax status.

     The Company has provided no income taxes on a pro forma basis due to the
losses incurred in all periods.

     The tax effects of temporary differences that give rise to significant
portions of the deferred tax assets and liabilities at December 31, 1999, are
presented below:

<TABLE>
<CAPTION>
                     DECEMBER 31, 1999
                     -----------------
<S>                                                           <C>
Deferred tax assets:
  Net operating loss carryforwards..........................  $ 2,274,000
  Depreciation and amortization.............................       54,000
  Option and warrant expense................................    7,903,000
                                                              -----------
Gross deferred tax assets...................................  $10,231,000
Valuation allowance for deferred tax assets.................   (7,692,000)
                                                              -----------
Net deferred tax assets.....................................    2,539,000
                                                              -----------
Deferred tax liabilities:
  Allowance for doubtful accounts...........................       18,000
  Intangibles...............................................    2,521,000
                                                              -----------
Net deferred tax liabilities................................    2,539,000
                                                              -----------
Deferred income taxes, net..................................  $        --
                                                              -----------
</TABLE>

     As of December 31, 1999, the Company had Federal and state net operating
loss carryforwards of approximately $5,400,000 which expire in 2019.

     In addressing the realizability of deferred tax assets, management
considers whether it is more likely than not that some portion or all of the
deferred tax assets will not be realized. The ultimate realization of deferred
tax assets is dependent on the generation of future taxable income during the
periods in which

                                      F-14
<PAGE>   104
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

those temporary differences become deductible. Management considers the
scheduled reversal of deferred tax liabilities, projected future taxable income
and tax planning strategies in making this assessment.

(11)  LEASES

     The Company is obligated under noncancelable operating leases for office
space, that expire at various dates through 2010. Future minimum lease payments
under noncancelable operating leases are approximately as follows:

<TABLE>
<CAPTION>
                  YEAR ENDING DECEMBER 31,
                  ------------------------
<S>                                                           <C>
2000........................................................  $  648,000
2001........................................................     664,000
2002........................................................     676,000
2003........................................................     705,000
2004........................................................     736,000
Thereafter..................................................   3,866,000
                                                              ----------
Total minimum lease payments................................  $7,295,000
                                                              ==========
</TABLE>

     Rent expense under operating leases was approximately $84,000, $91,000, and
$282,000 for the years ended December 31, 1997, 1998 and 1999, respectively.

(12)  PENSION PLANS

     The Company has two defined contribution plans under Section 401(k) of the
Internal Revenue Code that provide for voluntary employee contributions of 1 to
15 percent of compensation for substantially all employees. The Company
contributed $4,000 to one of the plans for the year ended December 31, 1999.

(13)  STOCK OPTIONS AND WARRANTS

  (a) Options

     In 1996, the Company adopted a Unit Option Plan. In September 1999, the
Company adopted the 1999 Equity Incentive Plan (the "Plan") to replace the Unit
Option Plan. Under the 1999 Equity Incentive Plan, the Company has the ability
to grant options to acquire up to 5.4 million shares of common stock to its
employees, directors, and service providers. Options under the Plan generally
expire after ten years and normally vest over a period of up to three years.
Options are generally granted at an exercise price equal to the fair value on
the grant date.

     In June 1999, the Company entered into an employment agreement with its
Chief Executive Officer ("Executive"). As part of this agreement, the Executive
was granted 350,000 unit options (875,000 shares) at an exercise price of $4.00
per unit ($1.60 per share) and the right to grant an additional 50,000 unit
options (125,000 shares) at an exercise price of $4.00 per unit ($1.60 per
share) to other key executives. These options expire in June 2009. In September
1999, the Company granted the Executive an additional 70,000 unit options
(175,000 shares) at an exercise price of $10.00 per unit ($4.00 per share).
These options expire in September 2009. Both grants of options became fully
vested in October 1999, as a result of the completion of the Company's initial
public offering. In October 1999, the Company recorded option and warrant
expense of $16.5 million, which is equal to the difference between the fair
value of the shares of Aether System Inc.'s common stock and the exercise price
measured at the date of the initial public offering, times the number of
options.

     The Company recorded total option and warrant expense of $40,277, $32,580
and $19,198,209 in 1997, 1998, and 1999, respectively. The Company expects to
record an additional $5.9 million in option and warrant expense through June 30,
2002 for the difference between the exercise price and the fair market value of
the units or stock at the date of grant.

                                      F-15
<PAGE>   105
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

     The Company applies APB 25 and related interpretations in accounting for
its unit option plan. Had compensation cost been recognized consistent with SFAS
No. 123, the Company's net loss would have increased by $24,000, $41,000, and
$4,243,000 for 1997, 1998, and 1999, respectively.

     The per share weighted-average value of options granted by the Company
during 1997, 1998, and 1999 was $0.16, $0.55, and $9.21, respectively, on the
date of grant using the Black-Scholes option-pricing model. These amounts were
calculated using an expected option life of 3 years and volatility of zero for
options granted in 1997 and 1998. In 1999, an expected option life of four years
and volatility of 70 percent was used for option grants. In addition, the
calculations assumed a risk-free interest rate of 5.77 percent to 6.25 percent
in 1997, 4.55 percent to 5.51 percent in 1998, and 4.60 percent to 6.11 percent
in 1999.

     A summary of the stock option and warrant activity, as adjusted for the
exchange of unit options and warrants for stock options, is as follows:

<TABLE>
<CAPTION>
                                          1997                      1998                      1999
                                 -----------------------   -----------------------   -----------------------
                                              WEIGHTED-                 WEIGHTED-                 WEIGHTED-
                                               AVERAGE                   AVERAGE                   AVERAGE
                                              EXERCISE                  EXERCISE                  EXERCISE
                                  NUMBER        PRICE       NUMBER        PRICE       NUMBER        PRICE
                                 OF SHARES   (PER SHARE)   OF SHARES   (PER SHARE)   OF SHARES   (PER SHARE)
                                 ---------   -----------   ---------   -----------   ---------   -----------
<S>                              <C>         <C>           <C>         <C>           <C>         <C>
Outstanding at beginning of
  year.........................    693,438      $0.40      1,000,000      $0.40      1,545,000      $0.85
Options and warrants granted...    306,562      $0.40        604,688      $1.54      2,763,856      $6.19
Options exercised..............         --         --             --         --       (365,498)     $0.54
Options canceled...............         --         --        (59,688)     $0.40        (10,000)     $1.49
                                 ---------      -----      ---------      -----      ---------      -----
Outstanding at end of year.....  1,000,000      $0.40      1,545,000      $0.85      3,933,358      $4.48
                                 =========      =====      =========      =====      =========      =====
Options exercisable at
  year-end.....................    596,720      $0.40        991,093      $0.50      2,450,657      $2.13
                                 =========      =====      =========      =====      =========      =====
</TABLE>

     The following table summarizes information about stock options at December
31, 1999:

<TABLE>
<CAPTION>
                                  OPTIONS OUTSTANDING                         OPTIONS EXERCISABLE
                   --------------------------------------------------   -------------------------------
                                        WEIGHTED
                                         AVERAGE         WEIGHTED                          WEIGHTED
                                        REMAINING    AVERAGE EXERCISE    NUMBER AT     AVERAGE EXERCISE
RANGE OF EXERCISE      NUMBER AT       CONTRACTUAL        PRICE         DECEMBER 31,        PRICE
     PRICES        DECEMBER 31, 1999      LIFE         (PER SHARE)          1999         (PER SHARE)
- -----------------  -----------------   -----------   ----------------   ------------   ----------------
                                       (IN YEARS)
<S>                <C>                 <C>           <C>                <C>            <C>
$ 0.40 - $ 0.40          617,314           2.19           $ 0.40            591,219         $0.40
$ 1.49 - $ 8.00        3,085,044           8.36           $ 2.98          1,859,438         $2.68
$52.25 - $79.75          231,000           9.90           $35.34                 --            --
                      ----------                                         ----------
                       3,933,358           6.83           $ 4.48          2,450,657         $2.13
                      ==========                                         ==========
</TABLE>

  (b) Warrants Issued to Members

     The Company granted warrants to purchase an aggregate 11,312 member units
(28,280 shares) at an exercise price of $0.01 per unit to Telcom Ventures and
Pyramid, as consideration for obtaining short-term loans (note 9).

     In connection with the sale of membership units to 3Com, the Company
granted a conditional warrant to 3Com to purchase 357,466 member units (893,665
shares) at an exercise price of $0.01 per unit. 3Com vested in 57,466 units
(143,665 shares) in June 1999 upon completion of a joint sales and marketing
plan. As a result, the Company recorded option and warrant expense of
approximately $862,000. 3Com vests in the remaining 300,000 warrants (750,000
shares) as follows: 150,000 warrants

                                      F-16
<PAGE>   106
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

(375,000 shares) upon the occurrence of the Company obtaining $6 million in
engineering services revenue from opportunities introduced by 3Com and 150,000
warrants (375,000 shares) upon the Company obtaining 6,000 wireless service
subscribers, all from opportunities introduced by 3Com. If and when it becomes
probable that 3Com will attain the specified milestones necessary for the
warrants to vest, the Company will begin to record an expense reflecting the
fair value of the warrants, which will be determined in part based on the market
price of the common stock. The Company would begin to recognize this expense
based on the probability that the milestones would be achieved, continuing
through the actual vesting date. The Company would initially estimate the amount
of the expense at the time of the determination that achievement is probable,
based in part on the market price of the common stock at that time. At the time
of the actual vesting, the fair value of the warrant would be remeasured and, if
different from the value used in initially estimating the expense, the
difference would be reflected as an additional charge or credit at that time. As
of December 31, 1999, the Company believes that it is not yet probable that 3Com
will attain the specified milestones relating to the remaining warrants to
purchase 750,000 shares and, accordingly, no expense relating to these warrants
has been recorded.

  (c) Notes Payable

     In September 1999, the Company entered into a $17,000,000 senior secured
credit facility with Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith
Incorporated. The credit facility was for a one-year term, with the possibility
of extension for an additional one-year term and accrued interest at a variable
rate. The credit facility was collateralized by substantially all of the assets
of the Company and contained certain financial covenants. In connection with the
credit facility, the Company granted warrants to Merrill Lynch Capital
Corporation to purchase up to 967,876 (2,419,690 shares) of the member units in
the Company which became exercisable for no consideration if the Company did not
repay the credit facility in a timely manner. On September 28, 1999, the Company
borrowed approximately $14,830,000 under the credit facility, primarily to pay
the purchase price of Mobeo. On October 26, 1999, the Company repaid the amount
outstanding under the credit facility and the warrants were canceled.

(14)  OTHER RELATED-PARTY TRANSACTIONS

  (a) Notes Receivable from Stockholder

     As of December 31, 1998 and 1999, the Company has amounts due from a
stockholder under short-term promissory notes of $137,879. The Company has
classified the notes as a reduction of stockholders' equity in the accompanying
consolidated statements of stockholders' equity. The notes are callable by the
Company at any time and bear interest at a rate of 7.5 percent per annum. The
notes and accrued interest were repaid in February 2000.

  (b) Consulting Agreements with Stockholders

     The Company derived approximately 34 percent and 39 percent of its revenue
for 1997 and 1998, respectively, from consulting services arrangements with one
and two of its stockholders, respectively. The Company had trade no accounts
receivable due from these stockholders as of December 31, 1998 and 1999,
respectively.

     As of December 31, 1997, the Company had received advances of $162,500 from
two of its members under consulting arrangements. This amount was recorded as
deferred revenue in the accompanying 1997 balance sheet, and was subsequently
recognized as revenue in 1998, when the related consulting services were
performed.

  (c) Purchases from Stockholder

     In 1998, the Company purchased approximately $560,000 of equipment and
inventory from a stockholder.

                                      F-17
<PAGE>   107
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

(15)  INVESTMENTS

     In February 1996, the Company made an investment of $750,000 to acquire a
20 percent interest in Real World Solutions, Inc. (RWS), a California company,
which was in the business of developing wireless middleware. The Company
accounted for its investment in RWS under the equity method and recorded its
proportionate share of losses generated by RWS. In July 1997, the Company sold
its interest in RWS to Puma Technology, Inc. (Puma), a Delaware company for
$205,000. The Company's carrying value of the investment in RWS as of the date
of sale was approximately $507,000 resulting in a realized loss on the sale of
the investment of approximately $302,000.

     Concurrently with the sale of the Company's investment in RWS to Puma, the
Company entered into an agreement with Puma for $175,000 to obtain perpetual
license rights for certain wireless middleware software. This amount was
capitalized and is being amortized over a three-year period.

     In December 1996, the Company made an investment of $48,000 in Navox, Inc.,
(Navox) a privately-held Delaware company which provides wireless communication,
location and security system development services. In June 1997, the Company
made an additional investment of $26,457 in Navox. The Company's investment
represents an approximate 5.5 percent interest in Navox, and includes
representation on Navox's board of directors. The Company accounts for its
investment in Navox under the equity method of accounting and records its
proportionate share of losses generated by Navox. The Company derived
approximately 50 percent and 2 percent of its revenue for 1997 and 1998,
respectively, under consulting arrangements with Navox. The Company had no trade
accounts receivables due from Navox as of December 31, 1998 and 1999,
respectively. The Company does not anticipate significant revenue from Navox in
the future.

(16)  RESERVED SHARE PROGRAM

     Prior to October 20, 1999, the effectiveness of the Company's registration
statement for its initial public offering, the Company sent a letter to
approximately 90 employees, officers and directors of the Company whom it had
designated as potential offerees of up to 390,000 shares of common stock in a
directed share program in connection with its initial public offering. These
materials were not accompanied by a preliminary prospectus and may have
constituted a prospectus that does not meet the requirements of the Securities
Act of 1933. If the mailing of these original materials did constitute a
violation of the Securities Act of 1933, the recipients of the letter who
purchased common stock in the initial public offering could have the right, for
a period of one year from the date of their purchase of common stock, to obtain
recovery of the consideration paid in connection with their purchase of common
stock or, if they have already sold the stock, sue the Company for damages
resulting from their purchase of common stock. These refunds or damages could
total up to approximately $6.2 million, based on the initial public offering
price of $16.00 per share, in the event that investors suffer a total loss of
their investment during this period and seek refunds or damages.

(17)  CONTINGENCY

     The Company has received two claims that it has infringed patents developed
by other parties. Management believes that these claims are without merit and
intends to contest them vigorously. If the Company is unsuccessful in its
defense, it could be liable for damages or could be required to enter into
costly royalty arrangements.

(18)  SUBSEQUENT EVENTS

  (a) Acquisition of LocusOne Communications, Inc.

     On February 3, 2000, the Company acquired all the outstanding common stock
and preferred stock of LocusOne Communications, Inc. ("LocusOne") for a purchase
price of approximately $40 million. LocusOne is a developer of wireless
communications for the supply chain management industry. The

                                      F-18
<PAGE>   108
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

acquisition will be accounted for under the purchase method of accounting.
Approximately $19.0 million of the purchase price is payable in the form of
non-interest bearing notes payable due no later than December 31, 2000.

  (b) Inciscent

     On February 7, 2000 the Company agreed to form a new company with
Metrocall, Inc., PSINet, Inc. and Hicks, Muse, Tate & Furst, Incorporated to be
called Inciscent. Inciscent will offer technology services to small and
medium-sized businesses and home office customers. The Company agreed to acquire
a 27.5% interest in Inciscent for $10 million. The Company also agreed to
acquire a 9.9% interest in Metrocall for $17 million.

  (c) Strategic Alliance with Reuters PLC

     On February 8, 2000, the Company entered into a non-binding letter of
intent with Reuters PLC to establish a new company focused on financial markets
in Europe. The Company plans to acquire a 60% interest in this new company for
$100 million.

  (d) Pending Acquisition of Riverbed Technologies, Inc.

     On February 9, 2000, the Company entered into an definitive merger
agreement to acquire Riverbed Technologies, Inc. ("Riverbed") for approximately
4,537,000 shares of common stock, plus the issuance of options to acquire
approximately 862,000 additional shares of common stock for replacement of
existing options of Riverbed's employees. Riverbed develops products to extend
the accessibility of applications and information from corporate networks and
databases to handheld devices. The acquisition will be accounted for under the
purchase method of accounting and is subject to regulatory approval and
shareholder vote by Riverbed shareholders.

                                      F-19
<PAGE>   109

                       REPORT OF INDEPENDENT ACCOUNTANTS

To the Board of Directors and Stockholders of Mobeo, Inc.

     In our opinion, the accompanying balance sheets and the related statements
of operations, changes in stockholders' equity (deficit) and cash flows, present
fairly, in all material respects, the financial position of Mobeo, Inc. at
December 31, 1997 and 1998, and the results of its operations and its cash flows
for the three years in the period ended December 31, 1998, in conformity with
generally accepted accounting principles. These financial statements are the
responsibility of the Company's management; our responsibility is to express an
opinion on these financial statements based on our audits. We conducted our
audits in accordance with generally accepted auditing standards which require
that we plan and perform the audit to obtain reasonable assurance about whether
the financial statements are free of material misstatement. An audit includes
examining, on a test basis, evidence supporting the amounts and disclosures in
the financial statements, assessing the accounting principles used and
significant estimates made by management, and evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for the opinion expressed above.

PricewaterhouseCoopers LLP
McLean, Virginia
March 10, 1999

                                      F-20
<PAGE>   110

                                  MOBEO, INC.

                                 BALANCE SHEETS

                                     ASSETS

<TABLE>
<CAPTION>
                                                                   DECEMBER 31,
                                                              -----------------------
                                                                 1997         1998
                                                              ----------   ----------
<S>                                                           <C>          <C>
Current assets:
  Cash and cash equivalents.................................  $  125,446   $  193,913
  Accounts receivable, net..................................     278,620      293,895
  Prepaid expenses and other................................      37,032       28,724
  Income tax refund receivable..............................      20,756       20,756
  Deferred income tax.......................................     142,365      186,549
                                                              ----------   ----------
          Total current assets..............................     604,219      723,837
Property and equipment, net.................................     321,876      405,148
Patents, net................................................          --       30,307
Deposits....................................................      24,475       23,609
Deferred income tax.........................................      71,476       14,542
                                                              ----------   ----------
          Total assets......................................  $1,022,046   $1,197,443
                                                              ==========   ==========

                   LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable..........................................  $  989,316   $1,130,184
  Accrued expenses..........................................     275,541      390,172
  Income tax payable........................................          --           --
  Capital lease obligations.................................      12,159           --
  Deferred revenue..........................................      71,220      104,170
                                                              ----------   ----------
          Total current liabilities.........................   1,348,236    1,624,526
                                                              ----------   ----------
Commitments and contingencies
Stockholders' equity (deficit):
  Common stock; no par value, 10,000 shares authorized,
     1,171 shares issued and outstanding....................          --           --
  Additional paid-in capital................................     172,625      172,625
  Accumulated deficit.......................................    (455,795)    (556,688)
  Notes receivable-related parties..........................     (43,020)     (43,020)
                                                              ----------   ----------
          Total stockholders' deficit.......................    (326,190)    (427,083)
                                                              ----------   ----------
          Total liabilities and stockholders' deficit.......  $1,022,046   $1,197,443
                                                              ==========   ==========
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-21
<PAGE>   111

                                  MOBEO, INC.

                            STATEMENTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                             FOR THE YEAR ENDED DECEMBER 31,
                                                           ------------------------------------
                                                              1996         1997         1998
                                                           ----------   ----------   ----------
<S>                                                        <C>          <C>          <C>
Service revenue..........................................  $6,484,864   $7,088,993   $8,580,786
Cost of services.........................................   2,947,185    3,148,051    3,040,743
                                                           ----------   ----------   ----------
Gross profit.............................................   3,537,679    3,940,942    5,540,043
                                                           ----------   ----------   ----------
Selling, general and administrative expenses:
  Sales and marketing....................................   1,641,502    1,812,696    2,302,360
  General and administrative.............................   1,149,218    1,937,829    2,706,544
  Research and development...............................      94,609      174,867      496,570
  Depreciation and amortization..........................     355,276      464,419      112,903
                                                           ----------   ----------   ----------
                                                            3,240,605    4,389,811    5,618,377
                                                           ----------   ----------   ----------
Other expense (income):
  Interest expense (income)..............................          --        2,628       (4,969)
  Loss on disposal of assets.............................          --      148,000       14,778
                                                           ----------   ----------   ----------
          Total other expenses (income)..................          --      150,628        9,809
                                                           ----------   ----------   ----------
Income (loss) before income taxes........................     297,074     (599,497)     (88,143)
Provision for (benefit from) income taxes................     120,150     (211,841)      12,750
                                                           ----------   ----------   ----------
Net income (loss)........................................  $  176,924   $ (387,656)  $ (100,893)
                                                           ==========   ==========   ==========
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-22
<PAGE>   112

                                  MOBEO, INC.

            STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT)

<TABLE>
<CAPTION>
                                                                                            NOTES
                                                               ADDITIONAL                 RECEIVABLE
                                                                PAID-IN     ACCUMULATED    RELATED
                                             SHARES   AMOUNT    CAPITAL       DEFICIT      PARTIES       TOTAL
                                             ------   ------   ----------   -----------   ----------   ---------
<S>                                          <C>      <C>      <C>          <C>           <C>          <C>
Balance at December 31, 1995...............  1,171     $--      $172,625     $(245,063)   $      --    $ (72,438)
  Issuance of notes receivable-related
    parties................................     --      --            --            --     (171,250)    (171,250)
  Net income...............................     --      --            --       176,924           --      176,924
                                             -----     ---      --------     ---------    ---------    ---------
Balance at December 31, 1996...............  1,171     $--      $172,625     $ (68,139)   $(171,250)   $ (66,764)
  Issuance of notes receivable-related
    parties................................     --      --            --            --      (65,603)     (65,603)
  Collections on notes receivable-related
    parties................................     --      --            --            --       71,250       71,250
  Allowance for notes receivable-related
    parties................................     --      --            --            --      122,583      122,583
  Net loss.................................     --      --            --      (387,656)          --     (387,656)
                                             -----     ---      --------     ---------    ---------    ---------
Balance at December 31, 1997...............  1,171      --       172,625      (455,795)     (43,020)    (326,190)
  Net loss.................................     --      --            --      (100,893)          --     (100,893)
                                             -----     ---      --------     ---------    ---------    ---------
Balance at December 31, 1998...............  1,171     $--      $172,625     $(556,688)   $ (43,020)   $(427,083)
                                             -----     ---      --------     ---------    ---------    ---------
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-23
<PAGE>   113

                                  MOBEO, INC.

                            STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                               FOR THE YEAR ENDED DECEMBER 31,
                                                              ---------------------------------
                                                                1996        1997        1998
                                                              ---------   ---------   ---------
<S>                                                           <C>         <C>         <C>
Cash flows from operating activities:
  Net income (loss).........................................  $ 176,924   $(387,656)  $(100,893)
  Adjustments to reconcile net income (loss) to net cash
    provided by operating activities:
    Bad debt expense........................................     23,976      62,956      51,620
    Deferred income taxes...................................     62,200    (211,841)     12,750
    Depreciation and amortization...........................    355,276     464,419     112,903
    Loss on disposal of assets..............................     57,472     148,009      14,778
    Allowance for notes receivable-related parties..........         --     122,583          --
    Changes in assets and liabilities:
       Accounts receivable..................................     74,989    (181,580)    (66,895)
       Income tax refund receivable.........................      6,414     (16,259)         --
       Restricted cash......................................     15,000          --          --
       Deposits, prepaid expenses and other.................     24,353     (30,990)      9,174
       Accounts payable and accrued expenses................    (66,407)    179,434     255,499
       Income tax payable...................................    (60,940)    (49,560)         --
       Deferred revenue.....................................   (127,115)      4,114      32,950
                                                              ---------   ---------   ---------
         Net cash provided by operating activities..........    542,142     103,629     321,886
                                                              ---------   ---------   ---------
Cash flows from investing activities:
  Purchase of property and equipment........................   (347,526)    (68,558)   (210,804)
  Payments to acquire patent................................         --          --     (30,456)
  Advances of notes receivable-related parties..............   (171,250)    (78,103)         --
  Collections on notes receivable-related parties...........         --      83,750          --
                                                              ---------   ---------   ---------
         Net cash used in investing activities..............   (518,776)    (62,911)   (241,260)
                                                              ---------   ---------   ---------
Cash flows from financing activities:
  Principal payments on capital leases......................    (42,268)    (48,414)    (12,159)
                                                              ---------   ---------   ---------
         Net cash used in financing activities..............    (42,268)    (48,414)    (12,159)
                                                              ---------   ---------   ---------
Net increase (decrease) in cash and cash equivalents........    (18,902)     (7,696)     68,467
Cash and cash equivalents at beginning of the year..........    152,044     133,142     125,446
                                                              ---------   ---------   ---------
Cash and cash equivalents at end of the year................  $ 133,142   $ 125,446   $ 193,913
                                                              =========   =========   =========
Supplemental disclosure of cash flow information:
  Cash paid for interest....................................  $  20,360   $  13,428   $   1,378
                                                              =========   =========   =========
  Cash paid for income taxes................................  $ 112,476   $  65,819   $      --
                                                              =========   =========   =========
  Supplemental disclosure of non-cash investing and
    financing activities:
    Allowance for notes receivable-related parties..........  $      --   $ 122,583   $      --
                                                              =========   =========   =========
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-24
<PAGE>   114

                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

1. ORGANIZATION

     DocuPro, Inc. was incorporated in the District of Columbia and commenced
operations in January 1989. In June 1998, DocuPro reincorporated in the state of
Delaware and in September 1998 changed its name to Mobeo, Inc. (the Company).
The Company is an electronic publisher specializing in providing financial
information over wireless networks. The Company's F/X Alert(R) service provides
major banks and financial institutions with continuous pricing and news
headlines of foreign exchange, government securities, and commodity markets on a
palm sized data terminal. The Company's PocketFutures(R) product provides the
individual futures trader with continuous pricing and news headlines of future
markets. Subsequent to December 31, 1998, the Company launched the Mobeo1.0(R)
product, designed for the individual equities trader.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

  Use of estimates

     The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenue and expenses during the reporting
period. Actual results could differ from those estimates.

  Cash and cash equivalents

     All highly liquid instruments with original maturities of three months or
less are considered to be cash equivalents. The Company invests its cash
balances in repurchase accounts with a large financial institution.

  Revenue recognition

     The Company enters into one year service contracts for providing financial
information over wireless networks. For substantially all its customers, the
Company bills on a monthly cycle and recognizes revenue monthly. Certain of the
Company's customers are billed in advance annually with revenue deferred and
recognized on a monthly basis over the life of the agreement. Non-refundable
activation fees are billed and recognized at the time of initial subscription.

  Concentration of credit risk

     Financial instruments that potentially subject the Company to
concentrations of credit risk consist principally of cash and cash equivalents
and accounts receivable. The Company maintains its cash and cash equivalents in
bank accounts which, at times, may exceed federally insured limits. The Company
has not experienced any losses in such bank accounts. The Company believes it is
not exposed to any significant credit risk on cash and cash equivalents. The
Company regularly monitors all outstanding accounts receivable balances to
assess collectibility. Accounts receivable as of December 31, 1997 and 1998, are
net of an allowance for doubtful accounts of $30,000 and $32,700, respectively.
The accounts receivable, which are not collateralized, are due mainly from banks
and financial institutions.

     Although the Company has sales on a national basis, 75% of their revenue
were derived in the New York City area. No individual accounts receivable were
greater than 10% of total accounts receivable as of December 31, 1997 and 1998.

                                      F-25
<PAGE>   115
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

  Property and equipment

     Property and equipment are recorded at cost. Property and equipment under
capital leases are recorded at the lower of their fair market value or the
present value of future minimum lease payments determined at the inception of
the lease.

     Amortization of leasehold improvements is recorded on a straight-line basis
over the shorter of the estimated useful life of the improvement or the term of
the lease. Amortization of property and equipment under capital leases is
recorded on a straight-line basis over the lease term. Property and equipment
under capital leases for which title passes to the Company at the conclusion of
the lease term is amortized on a straight line basis over the estimated useful
life of the related asset. Depreciation of other property and equipment is
recorded on a straight-line basis over expected useful lives of 3 to 10 years.

     When property and equipment is retired or otherwise disposed, the related
cost and accumulated depreciation are removed from the accounts and any
resulting gain or loss is reflected in income. Costs associated with repairs and
maintenance are expensed as incurred.

  Patents

     The cost of acquiring patents was approximately $30,000 as of December 31,
1998. Upon approval, the patents are to be amortized on a straight-line basis
over their estimated economic life, which is less than the statutory life of the
patents.

  Income taxes

     The Company accounts for income taxes in accordance with the liability
method. Deferred tax assets and liabilities are recognized for tax consequences
in future years for differences between financial reporting and tax bases of
assets and liabilities and are measured using the enacted tax rates and laws
that will be in effect when the differences are expected to reverse. The
provision for income taxes includes the current tax provision and the change
during the year in the net deferred tax liability or asset. A valuation
allowance is provided to reduce the deferred tax asset to a level which, more
likely than not, will be realized.

  Recent accounting pronouncements

     In June 1999, the FASB issued SFAS No. 137, Accounting for Derivative
Instruments and Hedging Activities-Deferral of the Effective Date of FASB No.
133 an amendment of FASB Statement No. 133, which defers the effective date of
SFAS No. 133 to all fiscal quarters of all fiscal years beginning after June 15,
2000. The Company will adopt SFAS No. 133 for the year ending December 31, 2000.
SFAS No. 133 requires that all derivative instruments be recorded on the balance
sheet at their fair value. Changes in the fair value of derivatives are recorded
each period in current earnings or other comprehensive income, depending on
whether a derivative is designated as part of a hedge transaction and, if it is,
the type of hedge transaction. Currently, the Company does not utilize
derivative instruments, therefore the adoption of SFAS No. 133 is not expected
to have a significant effect on the Company's results of operations or its
financial position.

  Reclassifications

     Certain amounts in the 1997 financial statements have been reclassified to
conform with the 1998 presentation.

                                      F-26
<PAGE>   116
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

3. PROPERTY AND EQUIPMENT

     Property and equipment consisted of the following:

<TABLE>
<CAPTION>
                                                                  DECEMBER 31,
                                                              ---------------------
                                                                1997        1998
                                                              ---------   ---------
<S>                                                           <C>         <C>
System hardware and software................................  $ 278,202   $ 196,038
Office furniture and equipment..............................    216,158     454,817
Leasehold improvements......................................     44,106      44,106
                                                              ---------   ---------
                                                                538,466     694,961
Less accumulated depreciation and amortization..............   (216,590)   (289,813)
                                                              ---------   ---------
                                                              $ 321,876   $ 405,148
                                                              =========   =========
</TABLE>

     During 1997, the Company leased certain office equipment under capital
leases. As of December 31, 1997, the cost of the office equipment related to
these capital leases was $44,035, and the accumulated amortization was $27,684.
These leases were fully amortized in 1998.

     During 1997, the Company reassessed the useful life of their pagers, which
are provided to customers upon activation of services at no fee. Since the
Company's service agreements are for a one-year period and subject to
cancellation, non-payment and non-return risk, management changed the estimated
useful life from three years to immediate expense recognition when the pagers
are acquired. As a result, the remaining net book value of pagers acquired prior
to 1997 of $228,000 was charged to depreciation expense for the year ended
December 31, 1997, while pagers purchased for the years ended December 31, 1997
and 1998 totaled $138,000 and $281,000, respectively.

     During 1997 and 1998, the Company disposed of certain system hardware and
software equipment with an original cost of $435,000 and $54,310, respectively,
and accumulated amortization of $287,000 and $35,675, respectively. The
resulting losses on disposals are included as a separate component on the
statement of operations.

4. INCOME TAXES

     The components of the provision for (benefit from) income taxes consisted
of the following:

<TABLE>
<CAPTION>
                                                                  YEAR ENDED
                                                                 DECEMBER 31,
                                                              -------------------
                                                                1997       1998
                                                              ---------   -------
<S>                                                           <C>         <C>
Current provision (benefit):
Federal.....................................................  $      --   $    --
State and local.............................................         --        --
                                                              ---------   -------
                                                                     --        --
                                                              ---------   -------
Deferred provision (benefit):
Federal.....................................................   (169,073)   10,200
State and local.............................................    (42,768)    2,550
                                                              ---------   -------
                                                               (211,841)   12,750
                                                              ---------   -------
Total provision for (benefit from) income taxes.............  $(211,841)  $12,750
                                                              =========   =======
</TABLE>

                                      F-27
<PAGE>   117
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

     Deferred income taxes reflect the net tax effects of temporary differences
between the carrying amounts of assets and liabilities for financial reporting
purposes and the amounts used for income tax purposes. Components of the
Company's net deferred tax assets and liabilities are as follows:

<TABLE>
<CAPTION>
                                                                 DECEMBER 31,
                                                              -------------------
                                                                1997       1998
                                                              --------   --------
<S>                                                           <C>        <C>
Current deferred tax assets
Allowance for doubtful accounts.............................  $ 64,848   $ 65,995
Deferred revenue............................................    30,264     36,611
Other.......................................................    10,714      3,163
Net operating loss carryback................................    36,539     80,780
                                                              --------   --------
Total current deferred tax assets...........................  $142,365   $186,549
                                                              --------   --------
Noncurrent deferred tax assets
Accumulated depreciation....................................    71,476     14,542
                                                              --------   --------
Total noncurrent deferred tax assets........................    71,476     14,542
                                                              --------   --------
Total deferred tax assets...................................  $213,841   $201,091
                                                              ========   ========
</TABLE>

     The change in the deferred tax assets in 1998 primarily represents the
effect of changes in the amounts of temporary differences. The Company's 1998
provision for income taxes differs from the provision that would have resulted
from applying the federal statutory rates to net loss before taxes due to
permanent differences primarily attributable to deductible business meals and
entertainment and other permanent differences of 48%. The Company believes it is
more likely than not to realize the net deferred tax asset and accordingly no
valuation allowance has been provided as of December 31, 1997 and 1998. This
conclusion is based on, (i) the Company's ability to carryback net operating
losses to offset taxable income from previous years and (ii) the Company's
expected future profitability.

5. PROFIT SHARING AND 401(K) PLANS

     The Company has a discretionary profit sharing plan and a self-directed
401(k) plan which cover all employees employed more than six months. Employees
become fully vested after three years of service. Employer contributions to the
profit sharing plan were $102,172 and $94,664 and contributions to the 401(k)
plan were $44,040 and $60,490 for the years ended December 31, 1997 and 1998,
respectively.

6. STOCK-BASED COMPENSATION

     On April 30, 1998, the Company adopted the Omnibus Stock Option Plan (the
Plan), under which incentive stock options, non-qualified stock options, stock
appreciation rights, restricted or unrestricted stock awards, phantom stock,
performance awards or any combination thereof may be granted to the Company's
employees and certain other persons in accordance with the Plan. The Board of
Directors, which administers the Plan, determines the number of options granted,
the vesting period and the exercise price. The Board of Directors may terminate
the Plan at any time. Options granted under the Plan generally vest over a four
year period and expire ten years after the date of grant. Prior to the common
stock becoming publicly traded, the Company retains the right of first offer to
buy the employees' shares at the offer price. At December 31, 1998, 48 shares
were reserved for issuance under the Plan.

                                      F-28
<PAGE>   118
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

     As of December 31, 1998, a total of 35 incentive stock options
respectively, had been granted to employees, at an exercise price of $3,250 per
share. The exercise price was established by the Board of Directors.

<TABLE>
<CAPTION>
                                                                                 WEIGHTED
                                                            INCENTIVE            AVERAGE
                                                              STOCK              EXERCISE
                                                             OPTIONS    PRICE     PRICE
                                                            ---------   ------   --------
<S>                                                         <C>         <C>      <C>
Options outstanding at December 31, 1997..................      --          --        --
Options granted...........................................      35      $3,250    $3,250
Options exercised.........................................      --          --
Options canceled..........................................      --          --        --
                                                               ---      ------    ------
Options outstanding at December 31, 1998..................      35      $3,250    $3,250
                                                               ---      ------    ------
Options granted...........................................      10      $3,250    $3,250
Options exercised.........................................      --          --
Options canceled..........................................      --          --        --
                                                               ---      ------    ------
Options outstanding at June 30, 1999 (unaudited)..........      45      $3,250    $3,250
                                                               ===      ======    ======
</TABLE>

     At December 31, 1998 no options were exercisable. The weighted-average fair
value of options granted during the year ended December 31, 1998.

     The Company measures compensation expense for its employee stock-based
compensation using the intrinsic value method and provides pro forma disclosures
of net loss as if the fair value method had been applied in measuring
compensation expense. Under the intrinsic value method of accounting for stock-
based compensation, when the exercise price of options granted to employees is
less than the fair value of the underlying stock on the date of grant,
compensation expense is to be recognized over the applicable vesting period. No
options granted through December 31, 1998 were less than fair value of the
underlying stock. Had the fair value method been applied, the Company's net loss
at December 31, 1998 would have been increased to the pro forma amounts
indicated below:

<TABLE>
<CAPTION>
                                                              DECEMBER 31,
                                                                  1998
                                                              ------------
<S>                                                           <C>
Net loss as reported........................................   $(100,893)
Pro forma net loss..........................................   $(103,313)
</TABLE>

     The fair value of each option is estimated on the date of grant using the
Black-Scholes option pricing model with the following weighted-average
assumptions used for grants during the year ended December 31, 1998: dividend
yield of 0%, expected volatility of 0%, risk-free interest rate of 5.07% and
expected term of 9 years.

     As of December 31, 1998, the weighted average remaining contractual life of
the options is 9.7 years.

7. COMMITMENTS AND CONTINGENCIES

  Data services and royalty arrangement

     In January 1995, the Company entered into a multi-year distribution
agreement with a provider of financial information for transmission to the
Company's customers. During 1998, the Company entered into two additional
multi-year agreements with new suppliers. Under these agreements, the Company
pays a monthly royalty to the data suppliers based on the number of wireless
units receiving data. Included in accounts payable at December 31, 1997 and 1998
and, respectively, related to purchases of financial information for
transmission to customers.

                                      F-29
<PAGE>   119
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

  Paging services

     In April 1994, the Company entered into a multi-year nonexclusive national
reseller agreement with a wireless messaging service provider. During 1998, the
Company entered into two additional multi-year nonexclusive national reseller
agreements with new suppliers. Under the terms of these agreements, the Company
is purchasing paging services from these providers for the purpose of marketing
and reselling such services to end users.

  Vulnerabilities due to certain concentrations

     The Company obtains all of its data from three sources and resells
primarily through one wireless messaging provider. Although there are a limited
number of data sources and messaging service providers, management believes that
they could obtain such services on terms comparable to the Company's existing
agreements. A change in suppliers, however, could cause delays in service, which
would adversely affect the Company's financial position, results of operations
and cash flows.

  Leases

     The Company leases office space in Bethesda, Maryland for its corporate
headquarters under an agreement which expires in December 1999. In addition, the
Company maintains facilities in New York, N.Y., under an agreement which expires
in 1999. The lease agreement for its corporate headquarters contains provisions
allowing free rent periods and periodic rate increases during the lease terms.
The Company recognizes rent expense under operating leases ratably over the
lease terms. As of December 31, 1997 and 1998, the Company had $13,000 and
$7,000, respectively, recorded as deferred rent included in accrued expenses.
Total rent expense was $238,783 and $239,936 for the years ended December 31,
1997 and 1998, respectively.

     In addition to office space, the Company leases an automobile under a 36
month operating lease, which expires in 1999.

     Future minimum lease payments under non-cancelable operating leases are as
follows:

<TABLE>
<S>                                                 <C>
1999..............................................  $201,695
</TABLE>

8. RELATED PARTY TRANSACTIONS

     In 1996, the Company advanced $171,250 to certain employees and
shareholders under notes receivable arrangements. During 1997, the Company
advanced an additional $78,103 under these arrangements, and received $83,750 in
collections on the notes receivables. There is no planned settlement of the
notes receivable balance in the foreseeable future, therefore the Company has
classified the amounts as a component of stockholders' equity (deficit). Under
these arrangements, the Company provided an allowance for doubtful accounts of
$122,583 to reflect the net realizable value of the notes at December 31, 1997
and 1998, respectively.

                                      F-30
<PAGE>   120

                          INDEPENDENT AUDITORS' REPORT

The Board of Directors and Stockholders
Riverbed Technologies, Inc.

     We have audited the accompanying balance sheets of Riverbed Technologies,
Inc. (the Company) as of December 31, 1998 and 1999, and the related statements
of operations, stockholders' equity (deficit), and cash flows for the period
from October 21, 1998 (date of inception) to December 31, 1998 and for the year
ended December 31, 1999. These financial statements are the responsibility of
the Company's management. Our responsibility is to express an opinion on these
financial statements based on our audits.

     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

     In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of Riverbed Technologies, Inc.
as of December 31, 1998 and 1999 and the results of its operations and its cash
flows for the period from October 21, 1998 (date of inception) to December 31,
1998 and for the year ended December 31, 1999, in conformity with generally
accepted accounting principles.

                                          KPMG LLP

McLean, Virginia
February 15, 2000

                                      F-31
<PAGE>   121

                          RIVERBED TECHNOLOGIES, INC.

                                 BALANCE SHEETS

<TABLE>
<CAPTION>
                                                                   DECEMBER 31,
                                                              -----------------------
                                                                1998         1999
                                                              --------    -----------
<S>                                                           <C>         <C>
                                       ASSETS
Current assets:
  Cash and cash equivalents.................................  $     --    $ 5,340,801
  Short-term investments....................................        --      3,936,542
  Accounts receivable.......................................    21,883        619,071
  Prepaids and other........................................        --        428,855
                                                              --------    -----------
          Total current assets..............................    21,883     10,325,269
Property and equipment, net.................................    48,161        718,075
                                                              --------    -----------
          Total assets......................................  $ 70,044    $11,043,344
                                                              ========    ===========
                     LIABILITIES, REDEEMABLE PREFERRED STOCK AND
                           STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable..........................................  $ 46,789    $   637,378
  Accrued expenses..........................................        --        497,135
  Deferred revenues.........................................     3,000         68,510
  Advance from stockholder..................................    81,834             --
  Note payable -- current portion...........................        --        120,578
                                                              --------    -----------
  Total current liabilities.................................   131,623      1,323,601
                                                              --------    -----------
Long-term liabilities:
  Note payable -- less current portion......................        --        241,155
                                                              --------    -----------
          Total liabilities.................................   131,623      1,564,756
                                                              --------    -----------
Series A preferred stock, convertible, $0.01 par value, zero
  and 3,500,000 shares authorized, issued and outstanding at
  December 31, 1998 and 1999, respectively (liquidation
  value $3,829,863).........................................        --      3,785,531
Series B preferred stock, convertible, $0.01 par value, zero
  and 4,145,211 shares authorized, issued and outstanding at
  December 31, 1998 and 1999, respectively (liquidation
  value $12,053,001)........................................        --     11,985,989
Stockholders' equity (deficit):
  Common stock, $0.01 par value, 100,000 and 14,354,789
     shares authorized at December 31, 1998 and 1999,
     respectively; 100,000 and 2,887,793 shares issued and
     outstanding at December 31, 1998 and 1999,
     respectively...........................................     1,000         28,878
  Additional paid-in-capital................................    (1,000)       561,033
  Accumulated deficit.......................................   (61,579)    (6,882,843)
                                                              --------    -----------
          Total stockholders' equity (deficit)..............   (61,579)    (6,292,932)
                                                              --------    -----------
  Commitments and contingencies
          Total liabilities, redeemable preferred stock and
            stockholders' equity (deficit)..................  $ 70,044    $11,043,344
                                                              ========    ===========
</TABLE>

                See accompanying notes to financial statements.
                                      F-32
<PAGE>   122

                          RIVERBED TECHNOLOGIES, INC.

                            STATEMENTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                                PERIOD FROM
                                                              OCTOBER 21, 1998
                                                           (DATE OF INCEPTION) TO       YEAR ENDED
                                                             DECEMBER 31, 1998       DECEMBER 31, 1999
                                                           ----------------------    -----------------
<S>                                                        <C>                       <C>
Software license revenue.................................         $     --              $   757,899
Maintenance, consulting and support revenue..............               --                  169,186
                                                                  --------              -----------
          Total revenue..................................               --                  927,085
Cost of software revenue.................................               --                  221,101
Cost of maintenance, consulting and support revenue......               --                  506,383
                                                                  --------              -----------
          Total cost of revenue..........................               --                  727,484
                                                                  --------              -----------
Gross profit.............................................               --                  199,601
Operating expenses:
Sales and marketing......................................           38,115                2,865,470
Research and development.................................           10,091                2,050,778
General and administrative...............................           13,373                1,055,071
Stock option expense.....................................               --                1,200,294
                                                                  --------              -----------
                                                                    61,579                7,171,613
                                                                  --------              -----------
          Operating loss.................................          (61,579)              (6,972,012)
Interest income (expense), net...........................               --                  150,748
                                                                  --------              -----------
Loss before income taxes.................................          (61,579)              (6,821,264)
Income taxes.............................................               --                       --
                                                                  --------              -----------
Net loss.................................................         $(61,579)             $(6,821,264)
Preferred stock dividend requirements....................               --                 (628,376)
                                                                  --------              -----------
Net loss available to common stockholders................         $(61,579)             $(7,449,640)
                                                                  ========              ===========
</TABLE>

                See accompanying notes to financial statements.
                                      F-33
<PAGE>   123

                          RIVERBED TECHNOLOGIES, INC.

                  STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT)

<TABLE>
<CAPTION>
                                    COMMON STOCK        ADDITIONAL
                                --------------------     PAID-IN-     ACCUMULATED
                                 SHARES        PAR       CAPITAL        DEFICIT         TOTAL
                                ---------    -------    ----------    -----------    -----------
<S>                             <C>          <C>        <C>           <C>            <C>
Balance at inception, October
  21, 1998....................         --    $    --    $       --    $        --    $        --
  Shares issued at
     inception................    100,000      1,000        (1,000)            --             --
  Net loss....................         --         --            --        (61,579)       (61,579)
                                ---------    -------    ----------    -----------    -----------
Balance at December 31,
  1998........................    100,000      1,000        (1,000)       (61,579)       (61,579)
  Stock split.................  1,722,917     17,229        17,229             --             --
  Issuance of common shares...    984,376      9,844            --             --          9,844
  Exercise stock options......     80,500        805         7,344             --          8,149
  Stock option expense........         --         --     1,200,294             --      1,200,294
  Preferred stock dividend
     requirements.............         --         --      (628,376)            --       (628,376)
  Net loss....................         --         --            --     (6,821,264)    (6,821,264)
                                ---------    -------    ----------    -----------    -----------
Balance at December 31,
  1999........................  2,887,793    $28,878    $  561,033    $(6,882,843)   $(6,292,932)
                                =========    =======    ==========    ===========    ===========
</TABLE>

                See accompanying notes to financial statements.
                                      F-34
<PAGE>   124

                          RIVERBED TECHNOLOGIES, INC.

                            STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                                PERIOD FROM
                                                              OCTOBER 21, 1998
                                                           (DATE OF INCEPTION) TO       YEAR ENDED
                                                             DECEMBER 31, 1998       DECEMBER 31, 1999
                                                           ----------------------    -----------------
<S>                                                        <C>                       <C>
Cash flow from operating activities:
  Net loss...............................................         $(61,579)             $(6,821,264)
  Adjustments to reconcile net loss to net cash used in
     operating activities
     Stock option expense................................               --                1,200,294
     Depreciation and amortization.......................               --                   97,050
     Changes in operating assets and liabilities:
       Increase in accounts receivable...................          (21,883)                (597,188)
       Increase in prepaids and other current assets.....               --                 (428,855)
       Increase in accounts payable and accrued
          expenses.......................................           46,789                1,087,724
       Increase in deferred revenue......................            3,000                   65,510
                                                                  --------              -----------
Net cash used in operating activities....................          (33,673)              (5,396,729)
                                                                  --------              -----------
Cash flows from investing activities:
     Purchases of property and equipment.................          (48,161)                (766,964)
     Purchase of short-term investments..................               --               (3,936,542)
                                                                  --------              -----------
  Net cash used in investing activities..................          (48,161)              (4,703,506)
                                                                  --------              -----------
Cash flows from financing activities:
     Advance (repayment) from stockholder................           81,834                  (81,834)
     Proceeds from the issuance of common stock and
       exercise of stock options.........................               --                   17,993
     Proceeds from the issuance of preferred stock, net
       of issuance costs.................................               --               15,143,144
     Proceeds from line of credit........................               --                  250,000
     Repayment on line of credit.........................               --                 (250,000)
     Proceeds from note payable..........................               --                  361,733
                                                                  --------              -----------
Net cash provided by financing activities................           81,834               15,441,036
Net increase in cash and cash equivalents................               --                5,340,801
Cash and cash equivalents, beginning of period...........               --                       --
                                                                  --------              -----------
Cash and cash equivalents, end of period.................         $     --              $ 5,340,801
                                                                  ========              ===========
Supplemental disclosure of cash flow information:
  Interest...............................................         $     --              $     4,355
  Income taxes...........................................         $     --              $        --
</TABLE>

                See accompanying notes to financial statements.
                                      F-35
<PAGE>   125

                          RIVERBED TECHNOLOGIES, INC.

                         NOTES TO FINANCIAL STATEMENTS

(1) ORGANIZATION AND DESCRIPTION OF BUSINESS

     Riverbed Technologies, Inc. (the "Company"), a Delaware corporation, was
formed on October 21, 1998 and is based in Vienna, Virginia.

     The Company designs, develops, sells and supports synchronization and
management software that enables handheld devices to be used as a natural
extension of the enterprise and systems enabling people to use wireless handheld
devices for data communications and transactions. The Company operates in a
highly competitive environment subject to rapid technological change and
emergence of new technology. Although management believes its services are
transferable to emerging technologies, rapid changes in technology could have an
adverse financial impact on the Company.

     The Company expects to expand its operations through continued capital
investment in new systems and services. The Company is not currently generating
sufficient cash flows from operations to support its current operating and
capital requirements. The Company has and will continue to be dependent upon its
stockholders and other financing sources to fund these requirements.

(2) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

  (a) Revenue Recognition

     Revenues are generated from licensing software and providing services,
including maintenance and technical support, training and consulting.

     In October 1997, the American Institute of Certified Public Accountants
("AICPA") issued Statement of Position ("SOP") No. 97-2, Software Revenue
Recognition. Subsequently, in March 1998 and December 1998, the AICPA issued SOP
98-4 and SOP 98-9, respectively, which defer until the Company's fiscal year
beginning January 1, 2000, the application of several paragraphs and examples in
SOP 97-2 that limit the definition of vendor specific objective evidence
("VSOE") for determining fair value of various elements in a multiple element
arrangement. The provisions of SOP 97-2 have been applied to transactions
entered into from the inception (October 21, 1998) of the Company. Management of
the Company does not believe that the adoption of the remaining portions of SOP
97-2, which were deferred by SOP 98-4 and SOP 98-9, will have a material impact
on the Company's financial statements.

     Software revenue consists of fees for licenses of the Company's software
products. The Company recognizes the revenue when the license agreement is
signed, the license fee is fixed and determinable, delivery of the software has
occurred, and collectibility of the fee is considered probable.

     Services revenue consists of maintenance and technical support, training
and consulting. Revenues from maintenance and technical support, which consists
of unspecified when-and-if-available product updates and customer telephone
support services, are recognized ratably over the term of the service period.
Other services revenues are recognized as the related services is provided.

  (b) Cost of Revenues

     The cost of software license revenues consists primarily of third party
royalties. The cost of maintenance, consulting and support revenue consists
primarily of personnel-related costs.

  (c) Software Development Costs

     Software development costs are accounted for in accordance with Statement
of Financial Accounting Standards ("SFAS") No. 86, Accounting for the Costs of
Computer Software to be Sold, Leased or Otherwise Marketed (the "Standard").
Under the Standard, capitalization of software development costs begins upon the
establishment of technological feasibility, subject to net realizable value
considerations.

                                      F-36
<PAGE>   126
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

To date, the period between achieving technological feasibility and the general
availability of such software has been short; therefore, software development
costs qualifying for capitalization have been immaterial. Accordingly, the
Company has not capitalized any software development costs and has charged all
such costs to research and development expense. Research and development costs
are expensed as incurred.

  (d) Advertising Expense

     Advertising costs are expensed as incurred. Advertising expense was $0 and
$343,000 for the period from October 21, 1998 (date of inception) to December
31, 1998 and for the year ended December 31, 1999, respectively.

  (e) Income Taxes

     The Company recognizes income taxes using the asset and liability method,
in accordance with Statement of Financial Accounting Standards ("SFAS") No. 109.
Under the asset and liability method, deferred tax assets and liabilities are
recognized for the future tax consequences attributable to differences between
the financial statement carrying amounts of existing assets and liabilities and
their respective tax bases. Deferred tax assets and liabilities are measured
using enacted tax rates expected to apply to taxable income in the years in
which those temporary differences are expected to be recovered or settled. The
effect of a tax rate change on deferred tax assets and liabilities is recognized
in income in the period that includes the enactment date.

  (f) Cash and Cash Equivalents

     Cash equivalents include all highly liquid investments with original
maturities of three months or less. Cash equivalents include approximately
$3,508,000 in money market accounts as of December 31, 1999.

  (g) Short-term Investments

     Short-term investments consist of highly liquid investments with original
maturities greater than three months and less than one year. Short-term
investments consisted of U.S. Treasury securities. Short-term investments are
recorded at their amortized cost which approximates fair value as of December
31, 1999.

  (h) Concentration of Credit Risk

     Financial instruments that potentially subject the Company to credit risk
consist of accounts receivable. The Company extends credit to its customers on
an unsecured basis in the normal course of business.

     For the year ended December 31, 1999, the Company derived approximately 60
percent of its revenue from three customers. As of December 31, 1999,
approximately 88 percent of the accounts receivable balance was due from four
customers.

  (i) Use of Estimates

     The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and the
disclosure of contingent assets and liabilities at the dates of the financial
statements and reported amounts of revenues and expenses during the reporting
period. Actual results could differ from those estimates.

                                      F-37
<PAGE>   127
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

  (j) Fair Value of Financial Instruments

     The carrying of the Company's financial instruments, including cash and
cash equivalents, accounts receivable, accounts payable, accrued expenses and
notes payable approximate their fair value because of the short duration of the
instruments.

  (k) Property and Equipment

     Property and equipment are stated at cost. Depreciation is calculated using
the straight-line method over the estimated useful lives of the assets, which
range from three to five years. The costs of leasehold improvements are
amortized using the straight-line method over the shorter of the lease term or
the estimated useful life of the asset.

  (l) Recovery of Long-Lived Assets

     The Company's policy is to review its long-lived assets for impairment
whenever events or changes in circumstances indicate that the carrying amount
may not be recoverable. The Company recognizes an impairment loss when the sum
of the expected future undiscounted cash flows is less than the carrying amount
of the asset. The measurement of the impairment losses to be recognized is based
upon the difference between the fair value and the carrying amount of the
assets.

  (m) Stock Compensation

     The Company accounts for stock-based employee compensation arrangements in
accordance with the provisions of Accounting Principles Board ("APB") No. 25,
"Accounting for Stock Issued to Employees," and complies with the disclosure
requirements of SFAS No. 123, "Accounting for Stock-Based Compensation." Under
APB No. 25, compensation cost, if any, is recognized over the respective vesting
period based on the difference, on the date of grant, between the fair value of
the Company's common stock and the exercise price. All stock-based awards to
non-employees are accounted for at their fair value in accordance with SFAS No.
123.

  (n) Other Comprehensive Loss

     The Company has adopted the provisions of SFAS No. 130, "Reporting
Comprehensive Income." SFAS No. 130 established standards for reporting
comprehensive income and its components in financial statements. Comprehensive
income, as defined, includes changes in equity of business enterprise during a
period from transactions and other events and circumstances from non-owner
sources. Other comprehensive income refers to revenue, expenses, gains and
losses that under generally accepted accounting principles are included in
comprehensive income, but excluded from net income. The Company has had no
transactions of this nature since its inception.

  (o) Recent Accounting Pronouncements

     In June 1998, the Financial Accounting Standards Board ("FASB") issued SFAS
No. 133, "Accounting for Derivative Instruments and Hedging Activities." The new
standard establishes accounting and reporting standards for derivative
instruments, including certain derivative instruments embedded in other
contracts, and for hedging activities. This statement, as amended, is effective
for all fiscal quarters beginning after June 15, 2000. The Company does not
expect SFAS No. 133 to have a material affect on its financial position or
results of operations.

                                      F-38
<PAGE>   128
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

(3) CAPITALIZATION

     The Company's Certificate of Incorporation, as amended, authorizes the
Company to issue 14,354,789 shares of common stock. As of December 31, 1999, the
Company had reserved shares of common stock for future issuance as follows:

<TABLE>
<S>                                                           <C>
Conversion of Series A Preferred Stock......................  3,500,000
Conversion of Series B Preferred Stock......................  4,145,412
Exercise of stock options pursuant to stock option plan.....  2,484,376
</TABLE>

     On October 21, 1998, the Company was formed and initially capitalized when
Noblestar Systems Corporation ("NobleStar") contributed certain intangible
assets in exchange for all 100,000 shares of the Company's authorized common
stock. On January 16, 1999, the Company effected a stock split of 18.22917 to 1
of its common stock. On January 20, 1999, the Company granted 984,376 shares of
common stock to two of its founders. In connection with this grant the Company
recorded stock option expense of approximately $778,000.

(4) PREFERRED STOCK

     In January 1999, the Company issued 3,500,000 shares of Series A Preferred
Stock ("Series A") at a price of $1.00 per share. Total proceeds, net of
offering expenses, were approximately $3,442,000.

     In October 1999, the Company issued 4,145,211 shares of Series B Preferred
Stock ("Series B") at a price of $2.84 per share. Total proceeds, net of
offering expenses, were approximately $11,701,000.

  (a) Voting Rights and Protective Provisions

     The Series A and B stockholders may vote with the common stock as a single
class on all actions to be taken by the stockholders. The Series A and B
stockholders each are entitled to elect one member of the Board of Directors
provided that at least 10 percent of authorized preferred stock of each class is
then outstanding. Furthermore, as long as 10 percent of each class of preferred
stock is outstanding, approval by at least two-thirds of holders of then
outstanding shares of Series A and B is required for: (i) changing rights,
preferences or privileges of each class; and (ii) issuing any equity security
having a preference or parity with each class with respect to voting, dividends,
liquidation or redemption. Finally, as long as 10 percent of each class of
preferred stock of each class is outstanding, approval by at least fifty percent
of the holders of then outstanding shares of Series and A and B is required for:
(i) the sale of the Company or substantially all of its assets; (ii) increasing
the authorized number of shares of preferred stock or common stock; (iii)
amending the Company's charter or bylaws; (iv) materially changing the Company's
business; (v) approving an annual budget and executive compensation plan,
including expenses greater than $100,000; or (vi) increasing the number of
directors of the Company.

  (b) Dividends

     Series A and B stock accrues cumulative dividends at rate of 10 percent per
annum, whether or not the dividends are declared by the Board of Directors.
Unpaid and undeclared dividends on Series A and Series B was approximately
$330,000 and $280,000, respectively, as of December 31, 1999.

  (c) Liquidation

     In the event of any liquidation, dissolution, or winding up of the
Corporation, either voluntary or involuntary, the holders of Series A and B
stock shall be entitled to receive an amount equal to the original share price
paid plus any unpaid cumulative dividends, whether or not declared. The Series A
and

                                      F-39
<PAGE>   129
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

B stockholders may also participate on an equal basis with the common stock in
any remaining assets after accumulated dividend are paid.

  (d) Redemption

     Series A and B stock are redeemable after October 2003 upon notice to the
Company by at least 50 percent of the holders of the then outstanding stock. The
redemption price shall equal the liquidation amount and is payable in three
annual installments beginning on the redemption date.

  (e) Conversion

     Series A and B stock is convertible on a one-for-one basis into shares of
common stock at the option of the holder. Series A and B stock is automatically
converted into common stock in the event of an initial public offering in which
the aggregate proceeds are not less than $15,000,000 and the Company's pre-
offering valuation is at least $150,000,000.

(5) PROPERTY AND EQUIPMENT

     Property and equipment consists of the following:

<TABLE>
<CAPTION>
                                                                 DECEMBER 31,
                                                              -------------------
                                                               1998        1999
                                                              -------    --------
<S>                                                           <C>        <C>
Computer hardware...........................................  $48,161    $638,594
Computer software...........................................       --     158,375
Furniture and fixtures......................................       --      18,156
                                                              -------    --------
                                                               48,161     815,125
Less: Accumulated depreciation..............................       --      97,050
                                                              -------    --------
                                                              $48,161    $718,075
                                                              =======    ========
</TABLE>

(6) LINE OF CREDIT AND NOTES PAYABLE

     In August 1999, the Company entered into a two-tranche credit facility with
a bank for a maximum available credit of $2,000,000. The assets and intellectual
properties of the Company collateralize the facility.

     The first tranche is an equipment note payable not to exceed $500,000, of
which, approximately $362,000 was payable at December 31, 1999. Amounts
available under the equipment note payable are limited to the advance purchase
of certain equipment through June 30, 2000. At December 31, 1999, there was
approximately $138,000 available to the Company under the equipment financing.
Principal is payable in thirty-six equal installments plus interest commencing
in January 2000. Any amounts drawn down between January and June 2000, and the
related interest, are due in thirty-six equal installments commencing in July
2000. Interest accrues on the unpaid principal at 1.625% above the bank's prime
rate (10.125% at December 31, 1999).

     The second tranche is a revolving line of credit not to exceed $1,500,000.
Amounts available under the revolving line of credit are limited by certain
asset based formulas and at December 31, 1999, there was approximately $836,000
available to the Company. All outstanding principal and interest is due on
January 31, 2001, the termination date of the revolving line of credit. Interest
accrues on the unpaid principal at 1.25% above the bank's prime rate (9.75% at
December 31, 1999) and is payable monthly.

     Finally, as of December 31, 1999, an irrevocable standby letter of credit
for $100,000 was established in lieu of a deposit on the lease for the Company's
headquarters.
                                      F-40
<PAGE>   130
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

(7) EMPLOYEE BENEFIT PLANS

  Retirement Plan

     As of March 1, 1999, the Company adopted a 401(k) Retirement Plan (the
"Plan") covering substantially all its employees. Participants in the Plan may
elect to defer up to 15% of their compensation. The Company may make a
discretionary matching contribution. In 1999, the Company matched 50% of
employee contributions up to 6% of compensation. The amount recorded as expense
for the year ended December 31, 1999 was approximately $25,000.

  Stock Option Plan

     During 1999, the Board of Directors adopted the 1999 Stock Option Plan
("the Stock Plan"). The Company has reserved up to 2,484,376 shares for issuance
under the Stock Plan. All of the Company's employees, officers, directors,
consultants and advisors are eligible to be granted options under the Stock
Plan. The exercise price and duration of the option are determined by the Board
at the date of grant. The options generally vest ratably over a period of 4
years, and generally expire in 10 years.

     The following table summarizes option activity for the year ended December
31, 1999. No options were granted in 1998.

<TABLE>
<CAPTION>
                                                                      1999
                                                              ---------------------
                                                                           WEIGHTED
                                                                           AVERAGE
                                                                           EXERCISE
                                                               SHARES       PRICE
                                                              ---------    --------
<S>                                                           <C>          <C>
Outstanding at beginning of year............................         --     $  --
Granted.....................................................  1,823,641      0.60
Exercised...................................................    (80,500)     0.10
Cancelled...................................................   (113,996)     0.10
                                                              ---------     -----
Outstanding at year end.....................................  1,629,145      0.65
                                                              =========     =====
Options exercisable at year end.............................    324,252      0.35
                                                              =========     =====
Options available for future grant..........................    660,735
                                                              =========
</TABLE>

     The per share weighted-average fair value of the options granted during
1999 was $1.90. The fair value of each option grant is estimated on the date of
grant, using the Black-Scholes options-pricing model with the following
assumptions: expected option life of 5 years, volatility of zero, risk-free
interest rate of 6.0% and dividend yield of zero percent.

<TABLE>
<CAPTION>
                    OPTIONS OUTSTANDING              OPTIONS EXERCISABLE
           -------------------------------------   -----------------------
              NUMBER       WEIGHTED                   NUMBER
           OUTSTANDING      AVERAGE     WEIGHTED   EXERCISABLE    WEIGHTED
                AT         REMAINING    AVERAGE       AS OF       AVERAGE
EXERCISE   DECEMBER 31,   CONTRACTUAL   EXERCISE   DECEMBER 31,   EXERCISE
 PRICES        1999          LIFE        PRICE         1999        PRICE
- --------   ------------   -----------   --------   ------------   --------
<S>        <C>            <C>           <C>        <C>            <C>
 $0.10        396,545        2.85        $0.10       216,336       $0.10
 $0.30        284,100        3.60        $0.30            --          --
 $0.85        854,000        3.83        $0.85       107,916        0.85
 $2.27         94,500        3.88        $2.27            --          --
            ---------                                -------       -----
            1,629,145        3.48        $0.65       324,252       $0.35
            =========                                =======
</TABLE>

                                      F-41
<PAGE>   131
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

     The Company applies APB Opinion No. 25 and related interpretations in
accounting for its stock options. The Company recorded compensation expense of
approximately $422,000 relating to options granted in the year ended December
31, 1999, equal to the difference between the estimated fair market value of the
Company's common stock on the grant date and the exercise price of the options.
The expense will be recognized ratably over the vesting period of the options,
which is generally four years.

     SFAS No. 123 requires pro forma net income (loss) disclosures as if the
Company had accounted for its stock options granted under the fair value method
prescribed by that statement. Had the Company used the fair value methodology
for determining compensation expense, the following table presents the pro forma
net income (loss) that would have been recorded by the Company for the options
granted during the year ended December 31, 1999:

<TABLE>
<CAPTION>
                                                                          YEAR ENDED
                                                                         DECEMBER 31,
                                                                             1999,
                                                                     ---------------------
<S>                                                   <C>            <C>
Net loss............................................  As reported         $(6,821,264)
                                                      Proforma            $(6,863,264)
</TABLE>

     The effects of applying SFAS No. 123 in this pro forma disclosure are not
indicative of future amounts.

(8) INCOME TAXES

     No provision for federal or state income taxes has been recorded as the
Company incurred net operating losses for all periods presented. As of December
31, 1999, the Company had net operating loss carryforwards available to offset
future taxable income of approximately $5,755,000 which expire in 2019. The
actual income tax benefit differed from the income tax benefit which would be
computed based upon the statutory federal tax rates as a result of recording a
valuation allowance.

     The tax effected amounts of temporary differences as of December 31, 1998
and 1999 are as follows:

<TABLE>
<CAPTION>
                                                                   DECEMBER 31,
                                                            --------------------------
                                                               1998           1999
                                                            -----------    -----------
<S>                                                         <C>            <C>
Deferred tax assets:
Net operating loss carryforward...........................  $        --    $ 2,359,000
Start-up costs............................................       25,000         19,000
Accrued vacation..........................................           --         10,000
                                                            -----------    -----------
Total deferred tax assets.................................       25,000      2,388,000
Valuation allowance.......................................      (25,000)    (2,340,000)
                                                            -----------    -----------
Net deferred tax assets...................................           --         48,000
                                                            -----------    -----------
Deferred tax liabilities:
Depreciation and amortization.............................           --         48,000
                                                            -----------    -----------
Total deferred tax liabilities............................           --         48,000
                                                            -----------    -----------
Net deferred taxes........................................  $        --    $        --
                                                            ===========    ===========
</TABLE>

(9) LEASES

     In December 1999, the Company entered into a long-term, non-cancelable
operating lease for its headquarters. The Company also leases other facilities
and certain office equipment under short-term, non-

                                      F-42
<PAGE>   132
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

cancelable operating leases. Future minimum lease payments under non-cancelable
operating leases are as follows:

<TABLE>
<CAPTION>
                                                               MINIMUM
                                                                LEASE
YEARS ENDING DECEMBER 31,                                      PAYMENTS
- -------------------------                                     ----------
<S>                                                           <C>
  2000......................................................  $  563,000
  2001......................................................     572,000
  2002......................................................     587,000
  2003......................................................      52,000
                                                              ----------
                                                              $1,774,000
                                                              ==========
</TABLE>

     Rent expense under operating leases was approximately $400 and $107,000,
for the period from October 21, 1998 (date of inception) to December 31, 1998
and the year ended December 31, 1999, respectively.

(10) RELATED PARTY TRANSACTIONS

     In 1998, the Company's operations were funded through non-interest bearing
advances made by Noblestar. As of December 31, 1998, approximately $82,000 was
due to Noblestar for such advances. These amounts were repaid in 1999.

(11) SUBSEQUENT EVENT

     On February 9, 2000, the Company entered into a definitive merger agreement
to be acquired by Aether Systems, Inc. for approximately 4,537,000 shares of
Aether's common stock, plus the issuance of options to acquire approximately
863,000 shares of Aether's common stock for replacement of existing options
issued to the Company's employees. The acquisition is subject to regulatory and
stockholder approval.

                                      F-43
<PAGE>   133

                         UNAUDITED PRO FORMA CONDENSED
                       CONSOLIDATED FINANCIAL INFORMATION

     The unaudited pro forma condensed consolidated financial information has
been prepared by Aether's management and gives effect to:

     (1) the acquisition of Mobeo, Inc. completed on September 28, 1999 and the
         acquisition of LocusOne Communications, Inc. completed on February 3,
         2000, which are collectively referred to in this "Unaudited Pro Forma
         Condensed Consolidated Financial Information" section as the "Completed
         Transactions", and

     (2) the pending acquisition of Riverbed Technologies, Inc. which is
         referred to in this "Unaudited Condensed Consolidated Pro Forma
         Financial Information" section as the "Pending Transaction".

     The pro forma condensed consolidated statement of operations for the year
ended December 31, 1999 has been prepared to give effect to the Mobeo, LocusOne
and Riverbed acquisitions as if they had occurred on January 1, 1999. The pro
forma as adjusted statement of operations gives effect to the Mobeo, LocusOne,
and Riverbed acquisitions plus the offering of shares covered by this prospectus
and the application of the net proceeds. The pro forma as further adjusted
statement of operations also gives effect to the concurrent offering of
convertible notes and the application of the net proceeds. The pro forma
condensed consolidated balance sheet as of December 31, 1999 gives effect to the
LocusOne and Riverbed acquisitions as if they had occurred on December 31, 1999.
The acquisition of Mobeo, which occurred prior to December 31, 1999, is already
reflected in the Company's historical consolidated balance sheet as of December
31, 1999. The pro forma as adjusted balance sheet gives effect to the LocusOne
and Riverbed acquisitions plus the offering of shares covered by this prospectus
and the application of the net proceeds. The pro forma as further adjusted
balance sheet also gives effect to the concurrent offering of convertible notes
and the application of the net proceeds.

     The pro forma adjustments, which are based upon available information and
certain assumptions that Aether believes are reasonable in the circumstances,
are applied to the historical financial statements of Aether, Mobeo, LocusOne
and Riverbed. The acquisitions are accounted for under the purchase method of
accounting. Aether's allocation of the purchase price is based upon the
estimated fair value of assets acquired and liabilities assumed in accordance
with Accounting Principles Board Opinion No. 16. The purchase price allocations
reflected in the accompanying unaudited pro forma condensed consolidated
financial statements may be different from the final allocation of the purchase
price and any such differences may be material.

     The accompanying unaudited pro forma condensed consolidated financial
information should be read in conjunction with the historical financial
statements and the notes thereto for Aether, Mobeo and Riverbed which are
included elsewhere in this prospectus. The unaudited pro forma condensed
consolidated financial information are provided for informational purposes only
and do not purport to represent what Aether's financial position or results of
operations would actually have been had the acquisitions occurred on such dates
or to project Aether's results of operations or financial position for any
future period.

                                      F-44
<PAGE>   134

                              AETHER SYSTEMS, INC.

            UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET

<TABLE>
<CAPTION>
                                                               AS OF DECEMBER 31, 1999
                                    -----------------------------------------------------------------------------
                                                                    AETHER AS
                                                    ADJUSTMENTS    ADJUSTED FOR    ADJUSTMENTS
                                     HISTORICAL    FOR COMPLETED    COMPLETED      FOR PENDING       PRO FORMA
                                       AETHER      TRANSACTIONS    TRANSACTIONS    TRANSACTION      CONSOLIDATED
                                    ------------   -------------   ------------   --------------   --------------
<S>                                 <C>            <C>             <C>            <C>              <C>
                                                     ASSETS
Current assets:
  Cash and cash equivalents.......  $ 78,541,792   $(21,163,853)   $ 57,377,939   $   (9,659,199)  $   47,718,740
  Short-term investments..........     2,091,962             --       2,091,962        3,936,542        6,028,504
  Trade accounts receivable,
    net...........................     1,002,845        256,423       1,259,268          619,071        1,878,339
  Inventory, net..................       688,494             --         688,494               --          688,494
  Prepaid expenses and other
    current assets................     4,994,965          6,573       5,001,538          428,855        5,430,393
                                    ------------   ------------    ------------   --------------   --------------
         Total current assets.....    87,320,058    (20,900,857)     66,419,201       (4,674,731)      61,744,470
Property and equipment, net.......     2,795,920        197,821       2,993,741          718,075        3,711,816
Intangible assets, net............    12,209,442     39,868,502      52,077,944    1,126,324,412    1,178,402,356
Other assets......................       208,698             --         208,698               --          208,698
                                    ------------   ------------    ------------   --------------   --------------
                                    $102,534,118   $ 19,165,466    $121,699,584   $1,122,367,756   $1,244,067,340
                                    ============   ============    ============   ==============   ==============
                                      LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable................  $  1,425,435   $     79,975    $  1,505,410   $      637,378   $    2,142,788
  Accrued expenses................     1,619,947             --       1,619,947          497,135        2,117,082
  Accrued employee compensation
    and benefits..................       971,110             --         971,110               --          971,110
  Deferred revenue................       175,193        110,469         285,662           68,510          354,172
  Notes payable current portion...                   18,975,022      18,975,022          120,578       19,095,600
                                    ------------   ------------    ------------   --------------   --------------
         Total current
           liabilities............     4,191,685     19,165,466      23,357,151        1,323,601       24,680,752
Notes payable-less current
  portion.........................            --             --              --          241,155          241,155
                                    ------------   ------------    ------------   --------------   --------------
                                       4,191,685     19,165,466      23,357,151        1,564,756       24,921,907
Stockholders' equity
  Preferred stock.................            --             --              --               --               --
  Common stock....................       271,543             --         271,543           45,373          316,916
  Additional paid-in-capital......   120,892,478             --     120,892,478    1,120,757,627    1,241,650,105
  Accumulated deficit.............   (22,613,640)            --     (22,613,640)              --      (22,613,640)
  Notes receivable from
    shareholder...................      (137,879)            --        (137,879)              --         (137,879)
  Unrealized loss on
    investments...................       (70,069)            --         (70,069)              --          (70,069)
                                    ------------   ------------    ------------   --------------   --------------
         Total stockholders'
           equity.................    98,342,433             --      98,342,433    1,120,803,000    1,219,145,433
                                    ------------   ------------    ------------   --------------   --------------
                                    $102,534,118   $ 19,165,466    $121,699,584   $1,122,367,756   $1,244,067,340
                                    ============   ============    ============   ==============   ==============
</TABLE>

                                      F-45
<PAGE>   135
                              AETHER SYSTEMS, INC.

    UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET -- (CONTINUED)

<TABLE>
<CAPTION>
                                                                    AS OF DECEMBER 31, 1999
                                   -----------------------------------------------------------------------------------------
                                                       PRO FORMA                              PRO FORMA         PRO FORMA
                                     PRO FORMA       STOCK OFFERING         PRO FORMA       DEBT OFFERING       AS FURTHER
                                    CONSOLIDATED      ADJUSTMENTS          AS ADJUSTED       ADJUSTMENTS         ADJUSTED
                                   --------------    --------------       --------------    -------------     --------------
<S>                                <C>               <C>                  <C>               <C>               <C>
                                                           ASSETS
Current assets:
  Cash and cash equivalents......  $   47,718,740     $306,569,168(A)     $  354,287,908    $192,800,000(B)   $  547,087,908
  Short-term investments.........       6,028,504               --             6,028,504              --           6,028,504
  Trade accounts receivable,
    net..........................       1,878,339               --             1,878,339              --           1,878,339
  Inventory, net.................         688,494               --               688,494              --             688,494
  Prepaid expenses and other
    current assets...............       5,430,393               --             5,430,393              --           5,430,393
                                   --------------     ------------        --------------    ------------      --------------
        Total current assets.....      61,744,470      306,569,168           368,313,638     192,800,000         561,113,638
Property and equipment, net......       3,711,816               --             3,711,816              --           3,711,816
Intangible assets, net...........   1,178,402,356               --         1,178,402,356              --       1,178,402,356
Other assets.....................         208,698      127,000,000(A)        127,208,698       7,200,000(B)      134,408,698
                                   --------------     ------------        --------------    ------------      --------------
                                   $1,244,067,340     $433,569,168        $1,677,636,508    $200,000,000      $1,877,636,508
                                   ==============     ============        ==============    ============      ==============
                                            LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable...............  $    2,142,788     $         --        $    2,142,788    $         --      $    2,142,788
  Accrued expenses...............       2,117,082               --             2,117,082              --           2,117,082
  Accrued employee compensation
    and benefits.................         971,110               --               971,110              --             971,110
  Deferred revenue...............         354,172               --               354,172              --             354,172
  Notes payable..................      19,095,600    (18,975,022)(A)             120,578              --             120,578
                                   --------------     ------------        --------------    ------------      --------------
        Total current
          liabilities............      24,680,752     (18,975,022)             5,705,730              --           5,705,730
Notes payable....................         241,155               --               241,155              --             241,155
  Convertible subordinated notes
    payable......................              --               --                    --     200,000,000(B)      200,000,000
                                   --------------     ------------        --------------    ------------      --------------
                                       24,921,907     (18,975,022)             5,946,885     200,000,000         205,946,885
Stockholders' equity
  Preferred stock................              --               --                    --              --                  --
  Common stock...................         316,916           24,913(A)            341,829              --             341,829
  Additional paid-in-capital.....   1,241,650,105      452,519,277(A)      1,694,169,382              --       1,694,169,382
  Accumulated deficit............     (22,613,640)                          (22,613,640)              --         (22,613,640)
  Notes receivable from
    shareholder..................        (137,879)              --             (137,879)              --            (137,879)
  Unrealized loss on
    investments..................         (70,069)              --              (70,069)              --             (70,069)
                                   --------------     ------------        --------------    ------------      --------------
        Total stockholders'
          equity.................   1,219,145,433      452,544,190         1,671,689,623              --       1,671,689,623
                                   --------------     ------------        --------------    ------------      --------------
                                   $1,244,067,340     $433,569,168        $1,677,636,508    $200,000,000      $1,877,636,508
                                   ==============     ============        ==============    ============      ==============
</TABLE>

- ---------------

(A) Reflects the sale of 2,346,219 shares of common stock in the offering
    assuming an offering price of $203 per share, after deducting underwriter's
    discounts and commissions and offering expenses, the exercise of options to
    purchase 145,000 shares by the selling stockholders, the repayment of
    approximately $19 million of indebtedness incurred in connection with the
    LocusOne acquisition, the investment of $100 million in the new company
    formed with Reuters, the investment of $17 million in Metrocall, and the
    investment of $10 million in Inciscent.

(B) Reflects the sale of an aggregate $200 million of      % convertible
    subordinated notes due in 2005 in the concurrent offering, less the
    underwriter's discounts and commissions and offering expenses recorded as
    deferred financing fees of $7.2 million.

                                      F-46
<PAGE>   136

                              AETHER SYSTEMS, INC.

            UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET
                     ADJUSTMENTS FOR COMPLETED TRANSACTIONS

<TABLE>
<CAPTION>
                                                             AS OF DECEMBER 31, 1999
                                                  ----------------------------------------------
                                                                  PRO FORMA         ADJUSTMENTS
                                                  HISTORICAL     ACQUISITION       FOR COMPLETED
                                                   LOCUSONE      ADJUSTMENTS       TRANSACTIONS
                                                  -----------    ------------      -------------
<S>                                               <C>            <C>               <C>
                                             ASSETS

Current assets:
  Cash and cash equivalents.....................  $    11,125    $(21,174,978)(A)  $(21,163,853)
  Trade accounts receivable, net................      256,423              --           256,423
  Prepaid expenses and other current assets.....        6,573              --             6,573
                                                  -----------    ------------      ------------
          Total current assets..................      274,121     (21,174,978)      (20,900,857)
Property and equipment, net.....................      197,821              --           197,821
Intangible assets, net..........................           --      39,868,502(A)     39,868,502
                                                  -----------    ------------      ------------
                                                  $   471,942    $ 18,693,524      $ 19,165,466
                                                  ===========    ============      ============

                              LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities:
  Accounts payable..............................  $    79,975    $         --      $     79,975
  Line of credit................................      858,000        (858,000)(A)            --
  Deferred revenue..............................      110,469              --           110,469
  Notes payable.................................           --      18,975,022(A)     18,975,022
                                                  -----------    ------------      ------------
          Total current liabilities.............    1,048,444      18,117,022        19,165,466
Redeemable preferred stock......................    2,250,000      (2,250,000)(A)            --
Stockholders' equity (deficit):
  Common stock..................................       45,000         (45,000)(A)            --
  Additional paid-in-capital....................      160,029        (160,029)(A)            --
  Accumulated deficit...........................   (3,031,531)      3,031,531(A)             --
                                                  -----------    ------------      ------------
Total stockholders' equity (deficit)............   (2,826,502)      2,826,502                --
                                                  -----------    ------------      ------------
                                                  $   471,942    $ 18,693,524      $ 19,165,466
                                                  ===========    ============      ============
</TABLE>

- ---------------

     (A) The LocusOne acquisition is to be accounted for as a purchase pursuant
         to Accounting Principles Board Opinion No. 16. Under such purchase
         accounting principles, LocusOne's assets acquired and liabilities
         assumed are required to be adjusted to their estimated fair values at
         the date of acquisition. The difference between the purchase cost and
         the fair value of LocusOne's net tangible and identifiable intangible
         assets is goodwill.

          The purchase price for LocusOne is as follows:

<TABLE>
<S>                                                       <C>
Cash consideration......................................  $21,024,978
Notes payable...........................................   18,975,022
Estimated costs and expenses............................      150,000
                                                          -----------
          Total purchase price..........................  $40,150,000
                                                          ===========
</TABLE>

          Aether made a payment of $20,000,000 at closing. In addition, Aether
          repaid outstanding indebtedness and certain legal fees of LocusOne
          totalling approximately $1,000,000. The remaining amount is payable in
          the form of two non-interest bearing notes payable. One note

                                      F-47
<PAGE>   137

          totaling $5.4 million is payable at the time of closing of this
          offering and the remaining $13.6 million is payable at December 31,
          2000.

          The allocation of the purchase price to the fair value of the assets
          acquired and liabilities assumed is preliminary and will be finalized
          following completion of a full valuation of the acquired assets and
          liabilities of LocusOne. The preliminary allocation of the purchase
          price is as follows:

<TABLE>
<S>                                                       <C>
Current assets..........................................  $   274,121
Fixed assets............................................      197,821
Current liabilities.....................................     (190,444)
Goodwill................................................   39,868,502
                                                          -----------
          Total purchase cost...........................  $40,150,000
                                                          ===========
</TABLE>

          The above purchase price allocation is preliminary and may change upon
          final determination of the fair value of assets and liabilities
          acquired. The Company has not specifically identified amounts to
          assign to intangibles other than goodwill; changes in the amounts
          allocated to such assets could result in changes to the amount of
          goodwill recorded, and such changes could be material. A preliminary
          amortization period for goodwill of five years has been used for
          purposes of the pro forma financial information.

                                      F-48
<PAGE>   138

                              AETHER SYSTEMS, INC.

            UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET
                      ADJUSTMENTS FOR PENDING TRANSACTION

<TABLE>
<CAPTION>
                                                             AS OF DECEMBER 31, 1999
                                                -------------------------------------------------
                                                                 PRO FORMA        ADJUSTMENTS FOR
                                                HISTORICAL      ACQUISITION           PENDING
                                                 RIVERBED       ADJUSTMENTS         TRANSACTION
                                                -----------    --------------     ---------------
<S>                                             <C>            <C>                <C>
                                             ASSETS
Current assets:
  Cash and cash equivalents...................  $ 5,340,801    $  (15,000,000)(A) $   (9,659,199)
  Short-term investments......................    3,936,542                --          3,936,542
  Trade accounts receivable, net..............      619,071                --            619,071
  Prepaid expenses and other current assets...      428,855                --            428,855
                                                -----------    --------------     --------------
          Total current assets................   10,325,269       (15,000,000)        (4,674,731)
Property and equipment, net...................      718,075                --            718,075
Intangible assets, net........................           --     1,126,324,412(A)   1,126,324,412
                                                ===========    ==============     ==============
                                                $11,043,344    $1,111,324,412     $1,122,367,756
                                                ===========    ==============     ==============
                              LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable............................  $   637,378    $           --     $      637,378
  Accrued expenses............................      497,135                --            497,135
  Notes payable...............................      120,578                --            120,578
  Deferred revenue............................       68,510                --             68,510
                                                -----------    --------------     --------------
          Total current liabilities...........    1,323,601                --          1,323,601
Notes payable.................................      241,155                --            241,155
                                                -----------    --------------     --------------
                                                  1,564,756                --          1,564,756
Redeemable preferred stock....................   15,771,520       (15,771,520)(A)             --
Stockholders' Equity
  Common stock................................       28,878            16,495(A)          45,373
  Additional paid-in-capital..................      561,033     1,120,196,594(A)   1,120,757,627
  Accumulated deficit.........................   (6,882,843)        6,882,843(A)              --
                                                -----------    --------------     --------------
Total stockholders' equity (deficit)..........   (6,292,932)    1,127,095,932      1,120,803,000
                                                ===========    ==============     ==============
                                                $11,043,344    $1,111,324,412     $1,122,367,756
                                                ===========    ==============     ==============
</TABLE>

- ---------------

(A) The pending acquisition of Riverbed will be accounted for as a purchase
    pursuant to Accounting Principles Board Opinion No. 16. Under such purchase
    accounting principles, Riverbed's assets acquired and liabilities assumed
    are required to be adjusted to their estimated fair values at the date of
    acquisition. The difference between the purchase cost and the fair value of
    Riverbed's net tangible and identifiable intangible assets is goodwill.

     The purchase price for Riverbed is as follows:

<TABLE>
<S>                                                    <C>
Issuance of Aether stock.............................  $  951,756,000
Issuance of replacement options......................     169,047,000
Estimated costs and expenses.........................      15,000,000
                                                       --------------
          Total purchase price.......................  $1,135,803,000
                                                       ==============
</TABLE>

     Aether will issue approximately 4,537,000 shares of its common stock for
all of the outstanding common and preferred stock of Riverbed. The Company has
valued the common stock based on the market price of Aether's common stock over
the period two days before and two days after the acquisition was agreed to and
announced, in accordance with FASB Emerging Issues Task Force Issue 95-19.
Aether has also reserved approximately 863,000 common shares for issuance upon
exercise of replacement options

                                      F-49
<PAGE>   139

to be issued to Riverbed employees. The value of these options was calculated
using the Black-Sholes option pricing model with the following assumptions:
expected dividend yield 0 percent, risk-free interest rate of 6.7 percent,
expected life of 5 years and volatility of 70 percent.

     The allocation of the purchase price to the fair value of the assets
acquired and liabilities assumed is preliminary and will be finalized following
completion of a full valuation of the assets and liabilities of Riverbed. The
preliminary allocation of the purchase price is as follows:

<TABLE>
<S>                                                    <C>
Current assets.......................................  $   10,325,269
Fixed assets.........................................         718,075
Current liabilities..................................      (1,323,601)
Long-term liabilities................................        (241,155)
Goodwill.............................................   1,126,324,412
                                                       --------------
          Total purchase cost........................  $1,135,803,000
                                                       ==============
</TABLE>

     The above purchase price allocation is preliminary and may change upon
final determination of the fair value of assets and liabilities acquired. The
Company has not specifically identified amounts to assign to intangibles other
than goodwill; changes in the amounts allocated to such assets could result in
changes to the amount of goodwill recorded, and such changes could be material.
A preliminary amortization period for goodwill of three years has been used for
purposes of the pro forma financial information. However, the results of the
full valuation may indicate that a portion of the purchase price should be
allocated to in-process research and development. Such amounts, if any, will be
expensed immediately following the date of acquisition. In addition, to the
extent that the full valuation indicates that a portion of the purchase price
should be allocated to identifiable intangible assets other than goodwill, the
Company may be required to record a deferred tax liability, as such intangible
assets would have no basis for tax reporting purposes.

                                      F-50
<PAGE>   140

                              AETHER SYSTEMS, INC.

       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS

<TABLE>
<CAPTION>
                                                    YEAR ENDED DECEMBER 31, 1999
                             ---------------------------------------------------------------------------
                                                             AETHER AS
                                             ADJUSTMENTS    ADJUSTED FOR    ADJUSTMENTS
                              HISTORICAL    FOR COMPLETED    COMPLETED      FOR PENDING      PRO FORMA
                                AETHER      TRANSACTIONS    TRANSACTIONS    TRANSACTION    CONSOLIDATED
                             ------------   -------------   ------------   -------------   -------------
<S>                          <C>            <C>             <C>            <C>             <C>
Subscriber revenue.........  $  3,731,792   $  7,467,834    $ 11,199,626   $          --   $  11,199,626
Engineering services
  revenue..................     2,594,476             --       2,594,476              --       2,594,476
Software and related
  services revenue.........            --      1,489,923       1,489,923         827,085       2,317,008
                             ------------   ------------    ------------   -------------   -------------
     Total revenue.........     6,326,268      8,957,757      15,284,025         827,085      16,111,110
Cost of subscriber
  revenue..................     2,109,807      2,529,296       4,639,103              --       4,639,103
Cost of engineering
  services revenue.........     1,366,426             --       1,366,426              --       1,366,426
Cost of software and
  related services
  revenue..................            --        813,203         813,203         727,484       1,540,687
                             ------------   ------------    ------------   -------------   -------------
     Total cost of
       revenue.............     3,476,233      3,342,499       6,818,732         727,484       7,546,216
                             ------------   ------------    ------------   -------------   -------------
          Gross profit.....     2,850,035      5,615,258       8,465,293          99,601       8,564,894
                             ------------   ------------    ------------   -------------   -------------
Operating expenses:
  Research and
     development...........     2,613,726        816,712       3,430,438       2,050,778       5,481,216
  General and
     administrative........     5,891,504      1,966,594       7,858,098       1,055,071       8,913,169
  Selling and marketing....     2,095,074      1,870,565       3,965,639       2,865,470       6,831,109
  Depreciation and
     amortization..........     1,089,013      9,820,307      10,909,320     375,441,471     386,350,791
  Option and warrant
     expense...............    19,198,209     13,124,936      32,323,145       1,200,294      33,523,439
                             ------------   ------------    ------------   -------------   -------------
                               30,887,526     27,599,114      58,486,640     382,613,084     441,099,724
                             ------------   ------------    ------------   -------------   -------------
          Operating loss...   (28,037,491)   (21,983,856)    (50,021,347)   (382,513,483)   (432,534,830)
Other income (expense):
  Interest income
     (expense), net........       (60,282)        17,594         (42,688)        150,748         108,060
  Equity in losses of
     investments...........    (2,425,000)            --              --              --      (2,425,000)
  Realized loss on sale of
     short-term
     investments...........      (168,721)            --              --              --        (168,721)
                             ------------   ------------    ------------   -------------   -------------
     Net loss..............  $(30,691,494)  $(21,966,262)   $(50,064,035)  $(382,362,735)  $(435,020,491)
                             ============   ============    ============   =============   =============
Pro forma net loss per
  share -- basic and
  diluted..................                                                                $      (16.90)
                                                                                           =============
Pro forma weighted average
  shares used in per share
  computations -- basic and
  diluted..................                                                                   25,744,511
                                                                                           =============
</TABLE>

                                      F-51
<PAGE>   141

                              AETHER SYSTEMS, INC.

                   UNAUDITED PRO FORMA CONDENSED CONSOLIDATED
                     STATEMENT OF OPERATIONS -- (CONTINUED)

<TABLE>
<CAPTION>
                                                         YEAR ENDED DECEMBER 31, 1999
                               ---------------------------------------------------------------------------------
                                                 PRO FORMA                         PRO FORMA         PRO FORMA
                                 PRO FORMA     STOCK OFFERING     PRO FORMA      DEBT OFFERING      AS FURTHER
                               CONSOLIDATED     ADJUSTMENTS      AS ADJUSTED      ADJUSTMENTS        ADJUSTED
                               -------------   --------------   -------------    -------------     -------------
<S>                            <C>             <C>              <C>              <C>               <C>
Subscriber revenue...........  $  11,199,626    $         --    $  11,199,626    $         --      $  11,199,626
Engineering services
  revenue....................      2,594,476              --        2,594,476              --          2,594,476
Software and related services
  revenue....................      2,317,008              --        2,317,008              --          2,317,008
                               -------------    ------------    -------------    ------------      -------------
    Total revenue............     16,111,110              --       16,111,110              --         16,111,110
Cost of subscriber revenue...      4,639,103              --        4,639,103              --          4,639,103
Cost of engineering services
  revenue....................      1,366,426              --        1,366,426              --          1,366,426
Cost of software and related
  services revenue...........      1,540,687              --        1,540,687              --          1,540,687
                               -------------    ------------    -------------    ------------      -------------
    Total cost of revenue....      7,546,216              --        7,546,216              --          7,546,216
                               -------------    ------------    -------------    ------------      -------------
         Gross profit........      8,564,894              --        8,564,894              --          8,564,894
                               -------------    ------------    -------------    ------------      -------------
Operating expenses:
  Research and development...      5,481,216              --        5,481,216              --          5,481,216
  General and
    administrative...........      8,913,169              --        8,913,169              --          8,913,169
  Selling and marketing......      6,831,109              --        6,831,109              --          6,831,109
  Depreciation and
    amortization.............    386,350,791              --      386,350,791              --        386,350,791
  Option and warrant
    expense..................     33,523,439              --       33,523,439              --         33,523,439
                               -------------    ------------    -------------    ------------      -------------
                                 441,099,724              --      441,099,724              --        441,099,724
                               -------------    ------------    -------------    ------------      -------------
         Operating loss......   (432,534,830)             --     (432,534,830)             --       (432,534,830)
Other income (expense):
  Interest income (expense),
    net......................        108,060              --          108,060     (14,440,000)(B)    (14,331,940)
  Equity in losses of
    investments..............     (2,425,000)             --       (2,425,000)             --         (2,425,000)
  Realized loss on sale of
    short-term investments...       (168,721)             --         (168,721)             --           (168,721)
                               -------------    ------------    -------------    ------------      -------------
    Net loss.................  $(435,020,491)   $         --    $(435,020,491)   $(14,440,000)     $(449,460,491)
                               =============    ============    =============    ============      =============
Pro forma net loss per
  share -- basic and
  diluted....................  $      (16.90)                   $      (15.41)                     $      (15.92)
                               =============                    =============                      =============
Pro forma weighted average
  shares used in per share
  computations -- basic and
  diluted....................     25,744,511                       28,235,730(A)                      28,235,730
                               =============                    =============                      =============
</TABLE>

- ---------------
(A) Reflects the sale of 2,346,219 shares of common stock in the offering and
    the exercise of options to purchase 145,000 shares by the selling
    stockholders.

(B) Reflects interest expense associated with the concurrent sale of $200
    million of convertible subordinated notes due in 2005 in the concurrent
    offering at an assumed interest rate of 6.5%.

                                      F-52
<PAGE>   142

                              AETHER SYSTEMS, INC.

       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
                     ADJUSTMENTS FOR COMPLETED TRANSACTIONS

<TABLE>
<CAPTION>
                          PERIOD FROM JANUARY 1, 1999               YEAR ENDED
                           THROUGH SEPTEMBER 28, 1999           DECEMBER 31, 1999
                          ----------------------------     ----------------------------    ADJUSTMENTS
                                           PRO FORMA                        PRO FORMA          FOR
                           HISTORICAL     ACQUISITION      HISTORICAL      ACQUISITION      COMPLETED
                            MOBEO(A)      ADJUSTMENTS       LOCUS ONE      ADJUSTMENTS     TRANSACTIONS
                          ------------   -------------     -----------     ------------    ------------
<S>                       <C>            <C>               <C>             <C>             <C>
Subscriber revenue......   $7,467,834     $        --      $        --     $         --    $  7,467,834
Software and related
  services revenue......           --              --        1,489,923               --       1,489,923
                           ----------     -----------      -----------     ------------    ------------
     Total revenue......    7,467,834              --        1,489,923               --       8,957,757
                           ----------     -----------      -----------     ------------    ------------
Cost of subscriber
  revenue...............    2,529,296              --               --               --       2,529,296
Cost of software and
  related services
  revenue...............           --              --          813,203               --         813,203
                           ----------     -----------      -----------     ------------    ------------
     Total cost of
       revenue..........    2,529,296              --          813,203               --       3,342,499
                           ----------     -----------      -----------     ------------    ------------
     Gross profit.......    4,938,538              --          676,720               --       5,615,258
                           ----------     -----------      -----------     ------------    ------------
Operating expenses:
  Research and
     development........      763,666              --           53,046               --         816,712
  General and
     administrative.....    1,994,525        (855,891)(C)      827,960               --       1,966,594
  Selling and
     marketing..........    2,069,413        (740,921)(C)      542,073               --       1,870,565
  Depreciation and
     amortization.......       82,915       1,667,511(B)        96,181        7,973,700(E)    9,820,307
  Option and warrant
     expense............           --       1,225,875(D)       299,561       11,599,500(F)   13,124,936
                           ----------     -----------      -----------     ------------    ------------
                            4,910,519       1,296,574        1,818,821       19,573,200      27,599,114
                           ----------     -----------      -----------     ------------    ------------
     Operating income
       (loss)...........       28,019      (1,296,574)      (1,142,101)     (19,573,200)    (21,983,856)
Other income (expense):
  Interest income
     (expense), net.....       17,594              --          (20,125)          20,125(G)       17,594
                           ----------     -----------      -----------     ------------    ------------
     Net income
       (loss)...........   $   45,613     $(1,296,574)     $(1,162,226)    $(19,553,075)   $(21,966,262)
                           ==========     ===========      ===========     ============    ============
</TABLE>

- ---------------

     (A) Reflects the historical results of Mobeo for the period from January 1,
         1999 to September 28, 1999. The results of Mobeo from September 29,
         1999 to December 31, 1999 are included in Aether's historical results
         for the year ended December 31, 1999.

     (B) Reflects the amortization of intangible assets, including goodwill,
         over three to seven year periods.

     (C) Reflects the elimination of compensation expense associated with
         certain management employees of Mobeo who ceased employment following
         the acquisition and who were not replaced.

     (D) Reflects the amortization of the estimated fair value of options
         granted to two former owners of Mobeo for consulting services over the
         two-year life of the consulting arrangement. Also reflects

                                      F-53
<PAGE>   143

         amortization of the intrinsic value of options granted to employees of
         Mobeo over the vesting period.

     (E) Reflects the amortization of intangible assets, including goodwill,
         over a five-year period. The estimated amount of amortization of
         intangible assets is based on a preliminary allocation of the purchase
         price and may change upon final determination, and such change could be
         material.

     (F) Reflects the amortization of the intrinsic value of options granted to
         employees of LocusOne over the three-year vesting period.

     (G) Reflects the elimination of interest expense, as LocusOne's outstanding
         debt was repaid by Aether as part of the acquisition.

                                      F-54
<PAGE>   144

                              AETHER SYSTEMS, INC.

       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
                      ADJUSTMENTS FOR PENDING TRANSACTION

<TABLE>
<CAPTION>
                                                         YEAR ENDED DECEMBER 31, 1999
                                              --------------------------------------------------
                                                               PRO FORMA         ADJUSTMENTS FOR
                                              HISTORICAL      ACQUISITION            PENDING
                                               RIVERBED       ADJUSTMENTS          TRANSACTION
                                              -----------    -------------       ---------------
<S>                                           <C>            <C>                 <C>
Software and related services revenue.....    $   927,085    $    (100,000)(A)    $     827,085
Cost of software and related services
  revenue.................................        727,484               --              727,484
                                              -----------    -------------        -------------
          Gross profit....................        199,601         (100,000)              99,601
                                              -----------    -------------        -------------
Operating expenses:
  Research and development................      2,050,778               --            2,050,778
  General and administrative..............      1,055,071               --            1,055,071
  Selling and marketing...................      2,865,470               --            2,865,470
  Depreciation and amortization...........             --      375,441,471(B)       375,441,471
  Option and warrant expense..............      1,200,294               --            1,200,294
                                              -----------    -------------        -------------
                                                7,171,613      375,441,471          382,613,084
                                              -----------    -------------        -------------
     Operating loss.......................     (6,972,012)    (375,541,471)        (382,513,483)
Other income (expense):
  Interest income (expense), net..........        150,748               --              150,748
                                              -----------    -------------        -------------
     Net loss.............................    $(6,821,264)   $(375,541,471)       $(382,362,735)
                                              ===========    =============        =============
</TABLE>

- ---------------

(A) Reflects the elimination of software revenue related to a sale by Riverbed
    to the Company. The cost of such sale has not been eliminated, as the
    amounts are insignificant.

(B) Reflects the amortization of intangible assets, including goodwill, over a
    three-year period. The purchase price allocation is preliminary and may
    change upon final determination of the fair value of assets and liabilities
    acquired. The Company has not specifically identified amounts to assign to
    intangibles other than goodwill; changes in the amounts allocated to such
    assets could result in changes to the amount of goodwill recorded, and such
    changes could be material. A preliminary amortization period for goodwill of
    three years has been used for purposes of the pro forma financial
    information. However, the results of the full valuation may indicate that a
    portion of the purchase price should be allocated to in-process research and
    development. Such amounts, if any, will be expensed immediately following
    the date of acquisition. In addition, to the extent that the full valuation
    indicates that a portion of the purchase price should be allocated to
    identifiable intangible assets other than goodwill, the Company may be
    required to record a deferred tax liability, as such intangible assets would
    have no basis for tax reporting purposes. This may result in recording
    additional goodwill amortization and a deferred tax benefit.

                                      F-55
<PAGE>   145

    ----------------------------------------------------------------------------
     ---------------------------------------------------------------------------

                                  3,000,000 SHARES

                                    [AETHER LOGO]

                                    COMMON STOCK

                          --------------------------------

                                     PROSPECTUS
                          --------------------------------

                                 MERRILL LYNCH & CO.

                                 ROBERTSON STEPHENS

                            DONALDSON, LUFKIN & JENRETTE

                             U.S. BANCORP PIPER JAFFRAY

                              BEAR, STEARNS & CO. INC.

                              FRIEDMAN BILLINGS RAMSEY

                                               , 2000

     ---------------------------------------------------------------------------
     ---------------------------------------------------------------------------
<PAGE>   146

       THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE
       MAY NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH
       THE SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS
       NOT AN OFFER TO SELL THESE SECURITIES AND IT IS NOT SOLICITING AN OFFER
       TO BUY THESE SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT
       PERMITTED.

                             SUBJECT TO COMPLETION
                 PRELIMINARY PROSPECTUS DATED FEBRUARY 22, 2000
PROSPECTUS
- -----------------------

                                3,000,000 SHARES

                                 [AETHER LOGO]

                                  COMMON STOCK
                            ------------------------

        Aether Systems, Inc. is selling 2,346,219 shares and Aether stockholders
are selling 653,781 shares. The international managers are offering 450,000
shares outside the U.S. and Canada and the U.S. underwriters are offering
2,550,000 shares in the U.S. and Canada.

        The shares are quoted on the Nasdaq National Market under the symbol
"AETH." On February 18, 2000, the last sale price of the shares as reported on
the Nasdaq National Market was $203 per share.

        Concurrent with this offering, we are offering $200,000,000 aggregate
principal amount of our   % convertible subordinated notes due 2005. The notes
will be convertible into shares of our common stock at the option of the holder.
We are offering the convertible notes through a separate prospectus. Completion
of the convertible notes offering is not a condition to the completion of this
offering.

        INVESTING IN THE COMMON STOCK INVOLVES RISKS THAT ARE DESCRIBED IN THE
"RISK FACTORS" SECTION BEGINNING ON PAGE 9 OF THIS PROSPECTUS.
                            ------------------------

<TABLE>
<CAPTION>
                                                          PER SHARE      TOTAL
                                                          ---------      -----
<S>                                                       <C>            <C>
Public offering price....................................  $             $
Underwriting discount....................................  $             $
Proceeds, before expenses, to Aether.....................  $             $
Proceeds, before expenses, to the selling stockholders...  $             $
</TABLE>

        The international managers may also purchase up to an additional 23,881
shares from Aether, and up to an additional 43,619 shares from the selling
stockholders, at the public offering price, less the underwriting discount,
within 30 days from the date of this prospectus to cover over-allotments. The
U.S. underwriters may similarly purchase up to an additional 135,327 shares from
Aether and up to an additional 247,173 shares from the selling stockholders.

        Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

        The shares will be ready for delivery on or about           , 2000.

                            ------------------------

MERRILL LYNCH INTERNATIONAL
    ROBERTSON STEPHENS INTERNATIONAL
       DONALDSON, LUFKIN & JENRETTE INTERNATIONAL
         U.S. BANCORP PIPER JAFFRAY
            BEAR, STEARNS INTERNATIONAL LIMITED
               FRIEDMAN, BILLINGS, RAMSEY INTERNATIONAL, LTD.
                            ------------------------

             The date of this prospectus is                , 2000.
<PAGE>   147

                                  UNDERWRITING

GENERAL

     We intend to offer the shares outside the U.S. and Canada through the
international managers and in the U.S. and Canada through the U.S. underwriters.
Merrill Lynch International, FleetBoston Robertson Stephens International
Limited, Donaldson, Lufkin & Jenrette International, U.S. Bancorp Piper Jaffray
Inc., Bear, Stearns International Limited and Friedman, Billings, Ramsey
International, Ltd. are acting as lead managers for the international managers
named below. Subject to the terms and conditions described in an international
purchase agreement among us, the selling stockholders and the international
managers, and concurrently with the sale of 2,550,000 shares to the U.S.
underwriters, we and the selling stockholders have agreed to sell to the
international managers, and the international managers severally have agreed to
purchase from us and the selling stockholders, the number of shares listed
opposite their names below.

<TABLE>
<CAPTION>
                                                                              NUMBER
               INTERNATIONAL MANAGER                                         OF SHARES
               ---------------------                                         ---------
<S>            <C>                                                           <C>
Merrill Lynch International................................................
FleetBoston Robertson Stephens International Limited.......................
Donaldson, Lufkin & Jenrette International.................................
U.S. Bancorp Piper Jaffray Inc.............................................
Bear, Stearns International Limited........................................
Friedman, Billings, Ramsey International, Ltd..............................
                                                                             ---------
               Total.......................................................    450,000
                                                                             =========
</TABLE>

     We and the selling stockholders have also entered into a U.S. purchase
agreement with the U.S. underwriters for sale of the shares in the U.S. and
Canada for whom Merrill Lynch, Pierce, Fenner & Smith Incorporated, FleetBoston
Robertson Stephens Inc., Donaldson, Lufkin & Jenrette Securities Corporation,
U.S. Bancorp Piper Jaffray Inc., Bear, Stearns & Co. Inc. and Friedman,
Billings, Ramsey & Co., Inc. are acting as U.S. representatives. Subject to the
terms and conditions in the U.S. purchase agreement, and concurrently with the
sale of 450,000 shares to the international managers pursuant to the
international purchase agreement, we and the selling stockholders have agreed to
sell to the U.S. underwriters, and the U.S. underwriters severally have agreed
to purchase 2,550,000 shares from us and the selling stockholders. The initial
public offering price per share and the total underwriting discount per share
are identical under the international purchase agreement and the U.S. purchase
agreement.

     The international managers and the U.S. underwriters have agreed to
purchase all of the shares sold under the international and U.S. purchase
agreements if any of these shares are purchased. If an underwriter defaults, the
international and U.S. purchase agreements provide that the purchase commitments
of the nondefaulting underwriters may be increased or the purchase agreements
may be terminated. The closings for the sale of shares to be purchased by the
international managers and the U.S. underwriters are conditioned on one another.

     We and the selling stockholders have agreed to indemnify the international
managers and the U.S. underwriters against certain liabilities, including
liabilities under the Securities Act, or to contribute to payments the
international managers and the U.S. underwriters may be required to make in
respect of those liabilities.

     The underwriters are offering the shares, subject to prior sale, when, as
and if issued to and accepted by them, subject to approval of legal matters by
their counsel, including the validity of the shares, and other conditions
contained in the purchase agreements, such as the receipt by the underwriters of
officer's certificates and legal opinions. The underwriters reserve the right to
withdraw, cancel or modify offers to the public and to reject orders in whole or
in part.
<PAGE>   148

COMMISSIONS AND DISCOUNTS

     The lead managers have advised us and the selling stockholders that the
international managers propose initially to offer the shares to the public at
the initial public offering price on the cover page of this prospectus and to
dealers at that price less a concession not in excess of $     per share. The
international managers may allow, and the dealers may reallow, a discount not in
excess of $     per share to other dealers. After the public offering, the
public offering price, concession and discount may be changed.

     The following table shows the public offering price, underwriting discount
and the proceeds before expenses to us and the selling stockholders. This
information assumes either no exercise or full exercise by the international
managers and the U.S. underwriters of their over-allotment options.

<TABLE>
<CAPTION>
                                                       PER SHARE    WITHOUT OPTION    WITH OPTION
                                                       ---------    --------------    -----------
<S>                                                    <C>          <C>               <C>
     Public offering price...........................     $              $                 $
     Underwriting discount...........................     $              $                 $
     Proceeds, before expenses, to Aether............     $              $                 $
     Proceeds, before expenses, to the selling
       stockholders..................................     $              $                 $
</TABLE>

     The expenses of the offering, not including the underwriting discount, are
estimated at $1.3 million and are payable by Aether.

OVER-ALLOTMENT OPTION

     We and the selling stockholders have granted options to the international
managers to purchase up to 67,500 additional shares at the public offering price
less the underwriting discount. The international managers may exercise these
options for 30 days from the date of this prospectus solely to cover any over-
allotments. If the international managers exercise these options, each will be
obligated, subject to conditions contained in the international purchase
agreement, to purchase a number of additional shares proportionate to that
international manager's initial amount reflected in the above table.

     We and the selling stockholders have also granted options to the U.S.
underwriters, exercisable for 30 days from the date of this prospectus to
purchase up to 382,500 additional shares to cover any over-allotments on terms
similar to those granted to the international managers.

INTERSYNDICATE AGREEMENT

     The international managers and the U.S. underwriters have entered into an
intersyndicate agreement that provides for the coordination of their activities.
Under the intersyndicate agreement, the international managers and the U.S.
underwriters may sell shares to each other for purposes of resale at the initial
public offering price, less an amount not greater than the selling concession.
Under the intersyndicate agreement, the international managers and any dealer to
whom they sell shares will not offer to sell or sell shares to U.S. or Canadian
persons or to persons they believe intend to resell to U.S. or Canadian persons,
except in the case of transactions under the intersyndicate agreement.
Similarly, the U.S. underwriters and any dealer to whom they sell shares will
not offer to sell or sell shares to persons who are non-U.S. or non-Canadian
persons or to persons they believe intend to resell to persons who are non-U.S.
or non-Canadian persons, except in the case of transactions under the
intersyndicate agreement.

NO SALES OF SIMILAR SECURITIES

     We and the selling stockholders and our executive officers and directors
have agreed, with exceptions, not to sell or transfer any common stock for 90
days after the date of this prospectus without first obtaining the written
consent of Merrill Lynch. Specifically, we and these other individuals have
agreed not to directly or indirectly

     - offer, pledge, sell or contract to sell any common stock,

     - sell any option or contract to purchase any common stock,
<PAGE>   149

     - purchase any option or contract to sell any common stock,

     - grant any option, right or warrant for the sale of any common stock,

     - lend or otherwise dispose of or transfer any common stock,

     - request or demand that we file a registration statement related to the
       common stock, or

     - enter into any swap or other agreement that transfers, in whole or in
       part, the economic consequence of ownership of any common stock whether
       any such swap or transaction is to be settled by delivery of shares or
       other securities, in cash or otherwise.

     This lockup provision applies to common stock and to securities convertible
into or exchangeable or exercisable for or repayable with common stock. It also
applies to common stock owned now or acquired later by the person executing the
agreement or for which the person executing the agreement later acquires the
power of disposition.

QUOTATION ON THE NASDAQ NATIONAL MARKET

     The shares are quoted on the Nasdaq National Market under the symbol
"AETH."

PRICE STABILIZATION, SHORT POSITIONS AND PENALTY BIDS

     Until the distribution of the shares is completed, SEC rules may limit
underwriters and selling group members from bidding for and purchasing our
common stock. However, the U.S. representatives may engage in transactions that
stabilize the price of the common stock, such as bids or purchases to peg, fix
or maintain that price.

     If the underwriters create a short position in the common stock in
connection with the offering, i.e., if they sell more shares than are listed on
the cover of this prospectus, the U.S. representatives may reduce that short
position by purchasing shares in the open market. The U.S. representatives may
also elect to reduce any short position by exercising all or part of the
over-allotment option described above. Purchases of the common stock to
stabilize its price or to reduce a short position may cause the price of the
common stock to be higher than it might be in the absence of such purchases.

     Neither we nor any of the underwriters makes any representation or
prediction as to the direction or magnitude of any effect that the transactions
described above may have on the price of the common stock. In addition, neither
we nor any of the underwriters makes any representation that the U.S.
representatives or the lead managers will engage in these transactions or that
these transactions, once commenced, will not be discontinued without notice.

UK SELLING RESTRICTIONS

     Each international manager has agreed that

     - it has not offered or sold and will not offer or sell any shares of
       common stock to persons in the United Kingdom, except to persons whose
       ordinary activities involve them in acquiring, holding, managing or
       disposing of investments (as principal or agent) for the purposes of
       their businesses or otherwise in circumstances which do not constitute an
       offer to the public in the United Kingdom within the meaning of the
       Public Offers of Securities Regulations 1995;

     - it has complied and will comply with all applicable provisions of the
       Financial Services Act 1986 with respect to anything done by it in
       relation to the common stock in, from or otherwise involving the United
       Kingdom; and

     - it has issued or passed on and will only issue or pass on in the United
       Kingdom any document received by it in connection with the issuance of
       common stock to a person who is of a kind described in Article 11(3) of
       the Financial Services Act 1986 (Investment Advertisements) (Exemptions)
       Order 1996 as amended by the Financial Services Act 1986 (Investment
       Advertisements) (Exemptions) Order 1997 or is a person to whom such
       document may otherwise lawfully be issued or passed on.
<PAGE>   150

NO PUBLIC OFFERING OUTSIDE THE UNITED STATES

     No action has been or will be taken in any jurisdiction (except in the
United States) that would permit a public offering of the shares of common
stock, or the possession, circulation or distribution of this prospectus or any
other material relating to our company, the selling stockholders or shares of
our common stock in any jurisdiction where action for that purpose is required.
Accordingly, the shares of our common stock may not be offered or sold, directly
or indirectly, and neither this prospectus nor any other offering material or
advertisements in connection with the shares of common stock may be distributed
or published, in or from any country or jurisdiction except in compliance with
any applicable rules and regulations of any such country or jurisdiction.

     Purchasers of the shares offered by this prospectus may be required to pay
stamp taxes and other charges in accordance with the laws and practices of the
country of purchase in addition to the offering price on the cover page of this
prospectus.

PASSIVE MARKET MAKING

     In connection with this offering, underwriters and selling group members
may engage in passive market making transactions in the common stock on the
Nasdaq National Market in accordance with Rule 103 of Regulation M under the
Exchange Act during a period before the commencement of offers or sales of
common stock and extending through the completion of distribution. A passive
market maker must display its bid at a price not in excess of the highest
independent bid of that security. However, if all independent bids are lowered
below the passive market maker's bid, that bid must then be lowered when
specified purchase limits are exceeded.

OTHER RELATIONSHIPS

     Some of the underwriters and their affiliates have engaged in, and may in
the future engage in, investment banking and other commercial dealings in the
ordinary course of business with us. They have received or may receive customary
fees and commissions for these transactions.
<PAGE>   151

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                                3,000,000 SHARES

                                 [AETHER LOGO]

                                  COMMON STOCK

                          ---------------------------

                                   PROSPECTUS
                          ---------------------------

                          MERRILL LYNCH INTERNATIONAL

                        ROBERTSON STEPHENS INTERNATIONAL

                   DONALDSON, LUFKIN & JENRETTE INTERNATIONAL

                           U.S. BANCORP PIPER JAFFRAY

                      BEAR, STEARNS INTERNATIONAL LIMITED

                 FRIEDMAN, BILLINGS, RAMSEY INTERNATIONAL, LTD.

                                            , 2000

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   152

     THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE
     MAY NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH
     THE SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS NOT
     AN OFFER TO SELL THESE SECURITIES AND IT IS NOT SOLICITING AN OFFER TO BUY
     THESE SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.

                             SUBJECT TO COMPLETION
                 PRELIMINARY PROSPECTUS DATED FEBRUARY 22, 2000
PROSPECTUS

                                  $200,000,000

                                 [AETHER LOGO]

                     % CONVERTIBLE SUBORDINATED NOTES DUE 2005
                            ------------------------

        The notes are convertible, at the option of the holder, at any time on
or prior to maturity into shares of common stock of Aether. The notes are
convertible at a conversion price of $       per share, which is equal to a
conversion rate of        shares per $1,000 principal amount of notes, subject
to adjustment. Our common stock is traded on the Nasdaq National Market under
the symbol "AETH." On February 18, 2000 the last sale price of our common stock
as reported on the Nasdaq National Market was $203 per share. The notes will not
be listed on any securities exchange or quoted on the Nasdaq Stock Market.

        We will pay interest on the notes on           and                of
each year, beginning           , 2000. The notes will mature on           ,
2005. We may redeem some or all of the notes at any time prior to           ,
2003 at a redemption price of $1,000 per $1,000 principal amount of the notes,
plus accrued and unpaid interest, if any, to the redemption date, if the closing
price of our common stock has exceeded 150% of the conversion price then in
effect. We may redeem some or all of the notes at any time on or after
          , 2003 at redemption prices described in this prospectus.

        The notes will be subordinated to our senior indebtedness. In addition,
the notes will effectively rank junior to our subsidiaries' liabilities.

        Concurrent with this offering, we are offering through a separate
prospectus 2,346,219 shares of our common stock and the Aether stockholders
identified in the separate prospectus are offering 653,781 shares of our common
stock. Completion of the common stock offering is not a condition to the
completion of this offering.

        INVESTING IN THE NOTES INVOLVES RISKS THAT ARE DESCRIBED IN THE "RISK
FACTORS" SECTION BEGINNING ON PAGE 11 OF THIS PROSPECTUS.
                            ------------------------

<TABLE>
<CAPTION>
                                            PER NOTE           TOTAL
                                            --------           -----
<S>                                         <C>                <C>
Public offering price(1)................            %          $
Underwriting discount...................            %          $
Proceeds,  before expenses, to Aether...            %          $
</TABLE>

               (1) Plus accrued interest from           , 2000, if settlement
        occurs after that date

        The underwriters may also purchase up to an additional $30,000,000
principal amount of notes from Aether at the public offering price, less the
underwriting discount, within 30 days from the date of this prospectus to cover
over-allotments.

        Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

        The notes will be ready for delivery in book-entry form only through The
Depository Trust Company on or about           , 2000.
                            ------------------------
MERRILL LYNCH & CO.                                           ROBERTSON STEPHENS
            DONALDSON, LUFKIN & JENRETTE
                         U.S. BANCORP PIPER JAFFRAY
                                    BEAR, STEARNS & CO. INC.
                                             FRIEDMAN BILLINGS RAMSEY
                            ------------------------
               The date of this prospectus is             , 2000.
<PAGE>   153

     DESCRIPTION OF INSIDE FRONT COVER: The inside front cover contains the
Aether Systems logo and the slogan: "Wireless solutions for a portable planet."
Above the logo and slogan is a photograph depicting a finger pointing to a
globe.
<PAGE>   154

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                PAGE
                                                                ----
<S>                                                           <C>
Prospectus Summary..........................................      4
Risk Factors................................................     11
Forward-Looking Statements..................................     21
Use of Proceeds.............................................     22
Price Range of Common Stock.................................     22
Dividend Policy.............................................     22
Concurrent Offering.........................................     23
Capitalization..............................................     24
Selected Consolidated Financial Data........................     26
Management's Discussion and Analysis of Financial Condition
  and Results of Operations.................................     28
Business....................................................     38
Management..................................................     57
Transactions Between Aether and its Officers, Directors or
  Significant Stockholders..................................     68
Principal Stockholders......................................     72
Description of Notes........................................     75
Description of Capital Stock................................     90
U.S. Federal Income Tax Considerations to U.S. Holders......     93
Shares Eligible for Future Sale.............................     96
Underwriting................................................     98
Legal Matters...............................................    101
Experts.....................................................    101
Where You Can Find More Information.........................    101
Index to Financial Statements...............................    F-1
</TABLE>

                         ------------------------------

     You should rely only on the information contained in this prospectus. We
have not, and the underwriters have not, authorized any other person to provide
you with different information. If anyone provides you with different or
inconsistent information, you should not rely on it. We are not, and the
underwriters are not, making an offer to sell these securities in any
jurisdiction where the offer or sale is not permitted. You should assume that
the information appearing in this prospectus is accurate only as of the date on
the front cover of this prospectus. Our business, financial condition, results
of operations and prospects may have changed since that date.

                                        3
<PAGE>   155

                               PROSPECTUS SUMMARY

     This summary does not contain all the information that may be important to
you. You should read the entire prospectus carefully, including the financial
data and related notes beginning on page F-1, before making an investment
decision.

OUR COMPANY

     We provide wireless data services, systems and software enabling people to
use handheld devices for mobile data communications and real-time transactions.
We design, develop, sell and support complete wireless systems for corporations
seeking to make data available to mobile workers or consumers. Our capabilities
include our wireless data engineering and development expertise, our wireless
integration software, our customer service and network operations center and,
following our acquisition of Riverbed Technologies, Inc., our mobile data
management software.

     We seek to develop and deliver wireless data services across a variety of
industries and market segments in the United States and internationally. Our
strategy initially focused on developing services for the financial services
sector, whose participants we believe are among the earliest adopters of
wireless data services. In the financial services industry, our current services
include TradeRunner, a real-time wireless trading and financial information
service offered to the online customers of Morgan Stanley Dean Witter Online,
the Reuters MarketClip service for financial market price quotes, alerts and
information and several services that deliver financial market information using
one- and two-way pagers. We currently are developing wireless trading and
financial services for other major financial institutions, including Charles
Schwab & Co., Inc.

     While seeking to extend our service offerings in the financial services
sector, we also seek to move into other industries and market segments. Since
January 2000, we have entered into the following acquisitions, investments,
agreements and letters of intent in pursuit of this strategy:

     - We agreed to acquire Riverbed, a company that develops and licenses
       mobile data management software. This pending acquisition gives us access
       to the industries Riverbed currently serves, including healthcare,
       transportation logistics and sales force automation.

     - We acquired LocusOne Communications, Inc., which develops wireless data
       systems for companies that distribute goods and services using their own
       delivery fleets. This acquisition extends our business to the
       transportation logistics and delivery industry.

     - We entered into a non-binding letter of intent with Reuters PLC to form a
       new company to develop wireless data systems in Europe, initially
       focusing on the financial services industry.

     - We agreed to form a new company, Inciscent, Inc., to develop wireless
       e-mail, two-way wireless data and Internet access and other applications
       for the small business and home office market segments. We agreed to form
       Inciscent with paging company Metrocall, Inc., Internet service provider
       PSINet Inc., investment firm Hicks, Muse, Tate & Furst Incorporated and
       other investors. As part of the investment, we also agreed to acquire
       approximately 9.9% of the outstanding capital stock of Metrocall for
       approximately $17 million.

     - We increased our investment in OmniSky Corporation (formerly doing
       business as OpenSky), a company we formed with 3Com Corporation. With our
       engineering assistance, OmniSky is developing wireless e-mail, Internet
       access and other electronic transactions primarily for the consumer
       market, and we have the right to offer these capabilities to our business
       customers.

     We have all the resources necessary to provide our customers with complete
wireless data systems. We have a large, experienced development team with 50
engineers, and with the acquisition of Riverbed we will add 34 engineers. We
have developed our package of wireless messaging software and software
development tools known as Aether Intelligent Messaging, or AIM, which serves as
a bridge to integrate diverse corporate in-house data systems with a wide
variety of wireless carrier networks and end-user devices. Through our pending
acquisition of Riverbed, we will also provide a suite of software products that
extend corporate data to mobile handheld devices. We operate our own
high-security network

                                        4
<PAGE>   156

operations center, which connects customer and other data to wireless networks,
and we maintain our own customer service center. We established the WAP
Enterprise Center, which is comprised of engineers who develop applications for
wireless phones that use the Wireless Application Protocol (so called WAP
smartphones) and the systems to support data communication to these devices. We
have also cultivated close relationships with major wireless network carriers,
including AT&T Wireless Services, Bell Atlantic Mobile and BellSouth Wireless
Data and mobile equipment and software vendors such as 3Com, Ericsson LM,
Novatel Wireless, Inc. and Phone.com, Inc.

     We believe we can provide our corporate customers with more attractive
service offerings by coupling general wireless applications like e-mail and
Internet access with custom corporate applications. We believe our involvement
with OmniSky and Inciscent will allow us to achieve this.

     Our Strategy.  Our strategy is to be the dominant provider of wireless data
services and systems to corporations by using our engineering expertise, our
software platforms, our customer service and network operations center and our
other resources. We seek to maximize recurring revenue by developing wireless
data services for a variety of industries and market segments in the United
States and internationally. We believe our capabilities and experience have
established us as an early market leader in wireless data services, and a key
element of our strategy is to move quickly into new opportunities to extend our
leadership position. Our strategy includes the following key elements:

     - Target a variety of industries and market segments for development of
       wireless data communications and services in the United States and
       internationally.

     - Continue to develop the market for existing and new services in the
       financial services sector.

     - Offer the widest range of software products to address every aspect of
       wireless integration and mobile data management for mobile workers and
       consumers.

     - Continue to develop mass-market wireless applications like e-mail and
       Internet access and bundle them with custom corporate applications.

     - Expand our customer base and strengthen the Aether brand through enhanced
       sales and marketing efforts.

     - Maintain and strengthen our strategic relationships with suppliers and
       customers.

     - Apply the expertise we gain through engineering services and research and
       development activities to emerging business opportunities.

     Operating results.  We had revenue of $1.8 million in 1997, $1.5 million in
1998 and $6.3 million in 1999. We had net losses of $2.7 million in 1997, $4.7
million in 1998 and $30.7 million in 1999. As of December 31, 1999, we had
cumulative losses of $38.5 million. On a pro forma basis, giving effect to the
acquisition of Mobeo, Inc. in September 1999 and LocusOne in February 2000, and
our pending acquisition of Riverbed, we had revenue of $16.1 million and net
losses of $435.0 million in 1999.

     Other information.  We are a Delaware corporation. In October 1999, we
completed our initial public offering of 6,900,000 shares of our common stock at
an initial offering price of $16.00 per share, which resulted in net proceeds of
approximately $101.1 million. All references to "we," "us," "our" or "Aether" in
this prospectus mean Aether Systems, Inc. and its subsidiaries or predecessors.

     Our principal executive offices are located at 11460 Cronridge Drive,
Owings Mills, Maryland 21117, and our telephone number is (410) 654-6400. We
maintain a Web site at www.aethersystems.com. Information contained in our Web
site does not constitute a part of this prospectus.

                                        5
<PAGE>   157

                                  THE OFFERING

     The following is a brief summary of some of the terms of this notes
offering. For a more complete description of the terms of the notes, see
"Description of Notes" in this prospectus.

Securities Offered..................     $200,000,000 aggregate principal amount
                                         (excluding $30,000,000 aggregate
                                         principal amount subject to the
                                         over-allotment option) of   %
                                         Convertible Subordinated Notes due
                                         2005.

Maturity............................               , 2005.

Interest............................       % per annum on the principal amount,
                                         payable semiannually on           and
                                                   of each year beginning
                                                   , 2000.

Conversion Rights...................     The notes are convertible, at the
                                         option of the holder, at any time on or
                                         before maturity into shares of our
                                         common stock at a conversion price of
                                         $          per share, which is equal to
                                         a conversion rate of           shares
                                         per $1,000 principal amount of notes.
                                         The conversion rate is subject to
                                         adjustment.

Ranking.............................     The notes will be unsecured and
                                         subordinated to our existing and future
                                         senior indebtedness. In addition, the
                                         notes will effectively rank junior to
                                         our subsidiaries' liabilities. As of
                                         February 15, 2000, we had approximately
                                         $19.0 million of senior indebtedness
                                         outstanding which we incurred in
                                         connection with our acquisition of
                                         LocusOne. The notes will also be
                                         subordinate to approximately $360,000
                                         of senior indebtedness which will be
                                         incurred by one of our subsidiaries in
                                         connection with our acquisition of
                                         Riverbed. Because the notes are
                                         subordinated, in the event of
                                         bankruptcy, liquidation or dissolution
                                         and acceleration of payment on the
                                         senior indebtedness, holders of the
                                         notes will not receive any payment
                                         until holders of any senior
                                         indebtedness we may incur have been
                                         paid in full. The indenture under which
                                         the notes will be issued will not
                                         prevent us or our subsidiaries from
                                         incurring senior indebtedness or other
                                         obligations.

Provisional Redemption..............     We may redeem the notes, in whole or in
                                         part, at any time before           ,
                                         2003 at a redemption price equal to
                                         $1,000 per $1,000 principal amount of
                                         notes to be redeemed plus accrued and
                                         unpaid interest, if any, to the date of
                                         redemption if the closing price of our
                                         common stock has exceeded 150% of the
                                         conversion price then in effect for at
                                         least 20 trading days within a period
                                         of 30 consecutive trading days ending
                                         on the trading day before the date of
                                         mailing of the provisional redemption
                                         notice. Upon any provisional
                                         redemption, we will make an additional
                                         payment in cash with respect to the
                                         notes called for redemption in an
                                         amount equal to $          per

                                        6
<PAGE>   158

                                         $1,000 principal amount of notes, less
                                         the amount of any interest actually
                                         paid on the note before the call for
                                         redemption. WE WILL BE OBLIGATED TO
                                         MAKE THIS ADDITIONAL PAYMENT ON ALL
                                         NOTES CALLED FOR PROVISIONAL
                                         REDEMPTION, INCLUDING ANY NOTES
                                         CONVERTED AFTER THE NOTICE DATE AND
                                         BEFORE THE PROVISIONAL REDEMPTION DATE.

Optional Redemption.................     We may redeem some or all of the notes
                                         at any time on or after           ,
                                         2003 at redemption prices described in
                                         this prospectus plus accrued and unpaid
                                         interest.

Change of Control...................     Upon a change of control event, each
                                         holder of the notes may require us to
                                         repurchase some or all of its notes at
                                         a purchase price equal to 100% of the
                                         principal amount of the notes plus
                                         accrued and unpaid interest. We may, at
                                         our option, instead of paying the
                                         change in control purchase price in
                                         cash, pay it in our common stock valued
                                         at 95% of the average of the closing
                                         sales prices of our common stock for
                                         the five trading days immediately
                                         preceding and including the third day
                                         prior to the date we are required to
                                         repurchase the notes. We cannot pay the
                                         change in control purchase price in
                                         common stock unless we satisfy the
                                         conditions described in the indenture
                                         under which the notes will be issued.

Use of Proceeds.....................     We currently intend to use the net
                                         proceeds from this offering and the
                                         concurrent common stock offering for
                                         the following:
                                         - $100 million to acquire a 60%
                                           interest in the company that is the
                                           subject of our letter of intent with
                                           Reuters;

                                         - $19 million to repay indebtedness
                                           incurred in connection with the
                                           LocusOne acquisition;

                                         - $17 million to make our investment
                                           in Metrocall;

                                         - $10 million to make our investment
                                           in Inciscent;

                                         - an estimated $25 million to enhance
                                           our sales and marketing activities;

                                         - fund potential future acquisitions
                                           and strategic investments; and

                                         - general corporate purposes.

DTC Eligibility.....................     Except as provided in this prospectus,
                                         the notes will be issued in fully
                                         registered book-entry form without
                                         coupons and in minimum denominations of
                                         $1,000. Purchasers will not receive
                                         individually certificated notes.
                                         Instead, the notes will be represented
                                         by one or more permanent global notes
                                         without coupons depos-

                                        7
<PAGE>   159

                                         ited with a custodian for and
                                         registered in the name of a nominee of
                                         The Depository Trust Company (DTC) in
                                         New York, New York. Beneficial
                                         interests in any global note will be
                                         shown on, and transfers thereof will be
                                         effected only through, records
                                         maintained by DTC and its direct and
                                         indirect participants, and any such
                                         beneficial interest may not be
                                         exchanged for certificated notes,
                                         except in limited circumstances
                                         described in this prospectus.
                                         Settlement and all secondary market
                                         trading activity for the notes will be
                                         in same day funds. See "Description of
                                         Notes -- Book-Entry System."

Listing.............................     The notes will not be listed on any
                                         securities exchange or quoted on the
                                         Nasdaq National Market. The
                                         underwriters have advised us that they
                                         intend to make a market in the notes.
                                         The underwriters are not obligated,
                                         however, to make a market in the notes,
                                         and any such market making may be
                                         discontinued at any time at the sole
                                         discretion of the underwriters without
                                         notice.

Nasdaq National Market symbol for
our common stock....................     AETH

                              CONCURRENT OFFERING

     Concurrently with our offering of notes, we are offering by means of a
separate prospectus 2,346,219 shares of our common stock and the Aether
stockholders identified in the prospectus for the common stock offering are
offering 653,781 shares of our common stock. The completion of the common stock
offering is not a condition to the completion of this offering.

                                        8
<PAGE>   160

                      SUMMARY CONSOLIDATED FINANCIAL DATA
                (in thousands, except share and per share data)

     The following table summarizes our consolidated statements of operations
for each of the years ended December 31, 1996, 1997, 1998 and 1999 and our
consolidated balance sheet as of December 31, 1999. The pro forma consolidated
financial information gives effect to (i) the Mobeo and LocusOne acquisitions
and the pending acquisition of Riverbed, (ii) the sale of $200 million of our
convertible notes in this offering and the application of the net proceeds as
described in "Use of Proceeds" on page 22 and (iii) the concurrent offering of
common stock and the application of the net proceeds as described in "Use of
Proceeds" on page 22. The pro forma net loss per share information gives effect
to our conversion from a limited liability company to a corporation immediately
prior to our initial public offering.

     We have provided the pro forma consolidated financial information for
informational purposes only and you should not assume that our results would
actually have been as shown if we had acquired Mobeo, LocusOne and Riverbed or
had completed the offerings on the assumed dates, or that the information
projects what our results will be as a result of the acquisitions or offerings.
The pro forma consolidated statement of operations information assumes that the
transactions occurred on January 1, 1999, and the pro forma consolidated balance
sheet information assumes that the transactions occurred on December 31, 1999.
See our, Mobeo's and Riverbed's financial statements and notes to those
statements included in this prospectus beginning on page F-1.
<TABLE>
<CAPTION>
                                                     YEAR ENDED DECEMBER 31,
                                 ----------------------------------------------------------------
                                                                                     1999 PRO FORMA
                                                                                     ------------

                                                    HISTORICAL
                                 -------------------------------------------------
                                    1996         1997         1998         1999      ACQUISITIONS
                                 ----------   ----------   ----------   ----------   ------------
<S>                              <C>          <C>          <C>          <C>          <C>
CONSOLIDATED STATEMENT OF
OPERATIONS DATA:
Revenue:
  Subscriber revenue...........  $       --   $      161   $      549   $    3,732    $   11,200
  Engineering services
    revenue....................       1,355        1,625          963        2,594         2,594
  Software and related services
    revenue....................          --           --           --           --         2,317
                                 ----------   ----------   ----------   ----------    ----------
  Total revenue................       1,355        1,786        1,512        6,326        16,111
Gross profit...................         348          493          411        2,850         8,565
Total operating expenses.......         601        2,801        5,178       30,887       441,100
                                 ----------   ----------   ----------   ----------    ----------
Operating loss.................        (253)      (2,308)      (4,767)     (28,037)     (432,535)
                                 ----------   ----------   ----------   ----------    ----------
Net loss.......................  $     (417)  $   (2,747)  $   (4,693)  $  (30,691)   $ (435,021)
                                 ==========   ==========   ==========   ==========    ==========
Ratio of earnings to fixed
  charges(1)...................          --           --           --           --
Pro forma net loss per
  share-basic and diluted......  $    (0.04)  $    (0.22)  $    (0.29)  $    (1.45)   $   (16.90)
                                 ==========   ==========   ==========   ==========    ==========
Pro forma weighted average
  shares used in computing net
  loss per share-basic and
  diluted......................  10,554,795   12,655,901   15,916,383   21,207,225    25,744,511
                                 ==========   ==========   ==========   ==========    ==========

<CAPTION>
                                        YEAR ENDED DECEMBER 31,
                                 -------------------------------------
                                          1999 PRO FORMA
                                 -------------------------------------
                                                       ACQUISITIONS,
                                 ACQUISITIONS AND    CONVERTIBLE NOTES
                                 CONVERTIBLE NOTES   AND COMMON STOCK
                                     OFFERING            OFFERINGS
                                 -----------------   -----------------
<S>                              <C>                 <C>
CONSOLIDATED STATEMENT OF
OPERATIONS DATA:
Revenue:
  Subscriber revenue...........     $   11,200          $   11,200
  Engineering services
    revenue....................          2,594               2,594
  Software and related services
    revenue....................          2,317               2,317
                                    ----------          ----------
  Total revenue................         16,111              16,111
Gross profit...................          8,565               8,565
Total operating expenses.......        441,100             441,100
                                    ----------          ----------
Operating loss.................       (432,535)           (432,535)
                                    ----------          ----------
Net loss.......................     $ (449,461)         $ (449,461)
                                    ==========          ==========
Ratio of earnings to fixed
  charges(1)...................                                 --
Pro forma net loss per
  share-basic and diluted......     $   (17.45)         $   (15.92)
                                    ==========          ==========
Pro forma weighted average
  shares used in computing net
  loss per share-basic and
  diluted......................     25,744,511          28,235,730
                                    ==========          ==========
</TABLE>

                                        9
<PAGE>   161

<TABLE>
<CAPTION>
                                                                  AS OF DECEMBER 31, 1999
                                             ------------------------------------------------------------------
                                                                               PRO FORMA
                                                         ------------------------------------------------------
                                                                                                ACQUISITIONS,
                                                                         ACQUISITIONS AND     CONVERTIBLE NOTES
                                                                         CONVERTIBLE NOTES    AND COMMON STOCK
                                              ACTUAL     ACQUISITIONS        OFFERING             OFFERINGS
                                             --------    ------------    -----------------    -----------------
<S>                                          <C>         <C>             <C>                  <C>
CONSOLIDATED BALANCE SHEET DATA:
  Cash and cash equivalents................  $ 78,542     $   47,719        $   94,544           $  547,088
  Working capital..........................    83,128         37,064           102,864              555,408
  Total assets.............................   102,534      1,244,067         1,425,092            1,877,637
  Total debt...............................        --         19,337           200,362              200,362
  Stockholders' equity.....................    98,342      1,219,145         1,219,145            1,671,690
</TABLE>

- ---------------
(1) Earnings were insufficient to cover fixed charges by $417, $2,747, $4,693
    and $30,691 for years 1996, 1997, 1998 and 1999, respectively, and $449,461
    pro forma for 1999.

                                       10
<PAGE>   162

                                  RISK FACTORS

     Investing in our notes involves risks.  You should carefully consider the
following risks together with the other information contained in this prospectus
before deciding to buy our notes.

OUR FUTURE RESULTS ARE UNCERTAIN BECAUSE OUR HISTORICAL REVENUE WAS DERIVED FROM
SERVICES OTHER THAN THOSE WE EXPECT TO BE THE FOCUS OF OUR BUSINESS IN THE
FUTURE.

     We only have a limited history selling our current services on which you
can evaluate our business, financial condition and operating results. Although
we commenced operations in January 1996, until March 1997 all of our revenue
came from engineering services and not from monthly service subscriptions or
software licensing which we now provide and which will be our focus in the
future. In 1997, 91.0% of our revenue was from engineering services and 9.0% was
from subscriber revenue. In 1998, 63.7% of our revenue was from engineering
services and 36.3% was from subscriber revenue. In 1999, 41.0% of our revenue
was from engineering services and 59.0% was from subscriber revenue. In 1999, on
a pro forma basis including Mobeo, LocusOne and our pending acquisition of
Riverbed, 16.1% of our revenue was from engineering services, 69.5% was from
subscriber revenue, and 14.4% was from software and related services revenue. We
have not had any AIM licensing revenue. In addition, our monthly service
subscriptions have come exclusively from subscriptions to our financial data and
online trading services, and our strategy includes development of services in
other industries. Because of this change in focus and our recent and pending
acquisitions, you should not rely on our past performance to evaluate our future
performance.

WE HAVE HISTORICALLY INCURRED LOSSES AND THESE LOSSES MAY INCREASE IN THE
FUTURE.

     We reported net losses of $2.7 million, $4.7 million and $30.7 million for
the years ended December 31, 1997, 1998 and 1999, respectively, and a net loss
of $435.0 million for the year ended December 31, 1999 on a pro forma basis
including the acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed. Our amortization of intangible assets and option and warrant expense
has grown significantly as a result of recent acquisitions. In addition, we
expect to continue to incur significant sales and marketing, systems development
and administrative expenses. Therefore, we will need to generate significant
revenue to become profitable and sustain profitability on a quarterly or annual
basis. We expect to continue to incur significant losses for the foreseeable
future. As a result, we may not be able to achieve profitability on a quarterly
or annual basis.

THERE IS NO ESTABLISHED MARKET FOR OUR FINANCIAL DATA AND OTHER SERVICES AND WE
MAY NOT BE ABLE TO SELL ENOUGH OF OUR SERVICES TO BECOME PROFITABLE.

     The markets for wireless data and transaction services are still emerging
and continued growth in demand for and acceptance of these services remains
uncertain. Current barriers to market acceptance of these services include cost,
reliability, functionality and ease of use. We cannot be certain that these
barriers will be overcome. We are currently developing financial trading
services for TD Waterhouse Investor Services, Inc. and Bear, Stearns & Co. Inc.
pursuant to preliminary agreements with these parties. We cannot assure you that
these parties will enter into contracts for our services or that products
developed for our other customers will result in revenue. Our competitors may
develop alternative wireless data communications systems that gain broader
market acceptance than our systems. If the market for our services does not
grow, or grows more slowly than we currently anticipate, we may not be able to
attract customers for our services and our revenues would be adversely affected.

OUR RECENT AND PENDING ACQUISITIONS, INVESTMENTS AND STRATEGIC ALLIANCES MAY NOT
DELIVER THE VALUE WE PAID OR WILL PAY FOR THEM AND MAY RESULT IN EXCESSIVE
EXPENSES IF WE DO NOT SUCCESSFULLY INTEGRATE THEM, OR IF THE COSTS AND
MANAGEMENT RESOURCES WE EXPEND IN CONNECTION WITH THE INTEGRATIONS EXCEED OUR
EXPECTATIONS.

     We expect that our recent and pending acquisitions, investments and
strategic alliances and any acquisitions, investments or strategic alliances we
may pursue in the future will have a continuing,

                                       11
<PAGE>   163

significant impact on our business, financial condition and operating results.
The value of these transactions may be less than the amount we paid for them or
invested if there is:

     - a decline of their position in the respective markets they serve; or

     - a decline in general of the markets they serve.

     The expenses associated with these transactions may be greater and their
revenue may be smaller than expected if:

     - we fail to assimilate the acquired assets with our pre-existing business;

     - we lose key employees of these companies or Aether as a result of the
       acquisitions;

     - our management's attention is diverted by other business concerns; or

     - we assume unanticipated liabilities related to the acquired assets.

     In addition, the companies we have acquired or invested in or may acquire
or invest in are subject to each of the business risks we describe in this
section, and if they incur any of these risks the businesses may not be as
valuable as the amount we paid. Further, we cannot guarantee that we will
realize the benefits or strategic objectives we are seeking to obtain by
acquiring these companies. In addition, we cannot assure you that our various
pending acquisitions, investments and strategic alliances will be completed on
the terms we describe, or at all.

WE MAY NOT ACHIEVE PROFITABILITY IF WE ARE UNABLE TO MAINTAIN, IMPROVE AND
DEVELOP THE WIRELESS DATA SERVICES WE OFFER.

     We believe that our future business prospects depend in part on our ability
to maintain and improve our current services and to develop new ones on a timely
basis. Our services will have to achieve market acceptance, maintain
technological competitiveness and meet an expanding range of customer
requirements. As a result of the complexities inherent in our service offerings,
major new wireless data services and service enhancements require long
development and testing periods. We may experience difficulties that could delay
or prevent the successful development, introduction or marketing of new services
and service enhancements. Additionally, our new services and service
enhancements may not achieve market acceptance. If we cannot effectively develop
and improve services we may not be able to recover our fixed costs or otherwise
become profitable.

IF WE DO NOT RESPOND EFFECTIVELY AND ON A TIMELY BASIS TO RAPID TECHNOLOGICAL
CHANGE, OUR SERVICES MAY BECOME OBSOLETE AND WE MAY LOSE SALES.

     The wireless and data communications industries are characterized by
rapidly changing technologies, industry standards, customer needs and
competition, as well as by frequent new product and service introductions. Our
services are integrated with wireless handheld devices and the computer systems
of our corporate customers. Our services must also be compatible with the data
networks of wireless carriers. We must respond to technological changes
affecting both our customers and suppliers. We may not be successful in
developing and marketing, on a timely and cost-effective basis, new services
that respond to technological changes, evolving industry standards or changing
customer requirements. Our ability to grow and achieve profitability will
depend, in part, on our ability to accomplish all of the following in a timely
and cost-effective manner:

     - effectively use and integrate new wireless and data technologies;

     - continue to develop our technical expertise;

     - enhance our wireless data, engineering and system design services;

     - develop applications for new wireless networks; and

     - influence and respond to emerging industry standards and other changes.

                                       12
<PAGE>   164

WE DEPEND UPON WIRELESS NETWORKS OWNED AND CONTROLLED BY OTHERS. IF WE DO NOT
HAVE CONTINUED ACCESS TO SUFFICIENT CAPACITY ON RELIABLE NETWORKS, WE MAY BE
UNABLE TO DELIVER SERVICES AND OUR SALES COULD DECREASE.

     Our ability to grow and achieve profitability partly depends on our ability
to buy sufficient capacity on the networks of wireless carriers such as AT&T
Wireless Services or Bell Atlantic Mobile and on the reliability and security of
their systems. All of our services are delivered using airtime purchased from
third parties. We depend on these companies to provide uninterrupted and "bug
free" service and would not be able to satisfy our customers' needs if they
failed to provide the required capacity or needed level of service. In addition,
our expenses would increase and our profitability could be materially adversely
affected if wireless carriers were to increase the prices of their services. Our
existing agreements with the wireless carriers generally have one-year terms.
Some of these wireless carriers are, or could become, our competitors and if
they compete with us they may refuse to provide us with their services.

OUR FAILURE TO DEVELOP RECOGNITION FOR THE AETHER BRAND COULD PREVENT US FROM
ACHIEVING A PROFITABLE LEVEL OF SALES.

     Our sales and marketing activities to date have been limited. Our sales and
marketing expenses were $840,455 for the year ended December 31, 1998 and $2.1
million for 1999. We intend to increase the market presence of our brand over
time, which will require us to substantially increase the amount we spend on
sales and marketing. We expect to spend an estimated $25 million in 2000 on
sales and marketing. We have applied for, but have not received, federal
trademark registrations for the names "Aether," "Aether Systems" and "AIM," and
we may not be able to use these names effectively or at all if we fail to obtain
such registrations due to conflicting marks or otherwise. As a result of our
recent acquisitions of Mobeo and LocusOne and our pending acquisition of
Riverbed, we expect to market our acquired products and services under their
existing brands. We may lose existing customers or fail to attract new customers
if these brands are not well received by our customers, if our marketing efforts
are not productive, if we are otherwise unsuccessful in increasing our brand
awareness or if our competition has greater brand recognition.

WE DEPEND ON THIRD PARTIES FOR THE MARKETING AND SALES OF SOME OF OUR SERVICES.
IF THE MARKETING EFFORTS OF THESE THIRD PARTIES ARE NOT EFFECTIVE, WE MAY NOT
ACHIEVE A PROFITABLE LEVEL OF SALES.

     We rely substantially on the efforts of others to market and sell some of
our wireless data communications services, in particular the online trading
services we have developed for Morgan Stanley Dean Witter Online and are
developing for Charles Schwab and other financial institutions. We believe that
third parties paid over $380,000 in marketing expenses in 1999 related to our
products, which represented 15% of sales and marketing expenses incurred in
connection with our services. We cannot control whether or how these third
parties who sell and market our services will perform their obligations to
market our services. If these third parties fail to market our services or their
efforts fail to result in new customers, we may be unable to attract new
customers and our revenue could be adversely effected.

WE MAY FAIL TO SUPPORT OUR ANTICIPATED GROWTH IN OPERATIONS WHICH COULD REDUCE
DEMAND FOR OUR SERVICES AND MATERIALLY ADVERSELY AFFECT OUR REVENUE.

     Our business strategy is based on the assumption that the number of
subscribers to our services, the amount of information they want to receive and
the number of services we offer will all increase. We must continue to develop
and expand our systems and operations to accommodate this growth. The expansion
and adaptation of our customer service and network operations center requires
substantial financial, operational and management resources. We may be unable to
expand our operations for one or more of the following reasons:

     - we may not be able to locate or hire at reasonable compensation rates
       qualified engineers and other employees necessary to expand our capacity;

     - we may not be able to obtain the hardware necessary to expand our
       capacity;
                                       13
<PAGE>   165

     - we may not be able to expand our billing and other related support
       systems; and

     - we may not be able to obtain sufficient additional capacity from wireless
       carriers.

     Due to the limited deployment of our services to date, the ability of our
systems and operations to connect and manage a substantially larger number of
customers while maintaining superior performance is unknown. Any failure on our
part to develop and maintain our wireless data services as we experience rapid
growth could significantly reduce demand for our services and materially
adversely affect our revenue.

WE DEPEND ON RECRUITING AND RETAINING KEY MANAGEMENT AND TECHNICAL PERSONNEL
WITH WIRELESS DATA AND SOFTWARE EXPERIENCE AND WE MAY NOT BE ABLE TO DEVELOP NEW
PRODUCTS OR SUPPORT EXISTING PRODUCTS IF WE CANNOT HIRE OR RETAIN QUALIFIED
EMPLOYEES.

     Because of the technical nature of our products and the dynamic market in
which we compete, our performance depends on attracting and retaining key
employees. Competition for qualified personnel in the wireless data and software
industries is intense and finding qualified personnel with experience in both
industries is even more difficult. We believe there are only a limited number of
individuals with the requisite skills in the field of wireless data
communication, and it is becoming increasingly difficult to hire and retain
these persons. Competitors and others have in the past attempted, and may in the
future attempt, to recruit our employees. Each of our engineers has entered into
a non-compete agreement with us for a period of ten months after they leave
Aether. These agreements will not prevent our engineers from leaving or working
for competitors relatively soon after they leave us.

     We currently maintain a key person life insurance policy for David S. Oros,
our chairman, chief executive officer and president. We do not maintain
insurance policies for any of our other employees.

WE MAY NOT HAVE ADEQUATELY PROTECTED OUR INTELLECTUAL PROPERTY RIGHTS, WHICH
COULD ALLOW COMPETITORS TO DEVELOP SIMILAR PRODUCTS USING SIMILAR TECHNOLOGY AND
THUS REDUCE OUR SALES AND REVENUE.

     We have attempted to protect our technology, including the technology we
have obtained or will obtain in our acquisition, through patent, trademark and
copyright protection, as well as through trade secret laws and non-competition
and non-disclosure agreements with key employees. Patents may infringe on valid
patents held by third parties, or patents held by third parties may limit the
scope of any patents we receive. In particular, the patent we expect to acquire
in our acquisition of Riverbed covers a technology that is subject to a number
of patents. In addition, Riverbed has no international patent protection in its
technology. If we are not adequately protected, other companies with sufficient
engineering expertise could quickly develop competing products based on our
intellectual property and reduce our sales and thus our revenue.

WE MAY BE SUED BY THIRD PARTIES FOR INFRINGEMENT OF THEIR INTELLECTUAL PROPERTY
RIGHTS AND INCUR COSTS OF DEFENSE AND POSSIBLY ROYALTIES OR LOSE THE RIGHT TO
USE TECHNOLOGY IMPORTANT TO PROVIDING OUR SERVICES.

     The telecommunications and software industries are characterized by the
existence of a large number of patents and frequent litigation based on
allegations of patent infringement or other violations of intellectual property
rights. As the number of participants in our market increases, the possibility
of an intellectual property claim against us could increase. We have received
two claims that we have infringed patents developed by other parties. Although
we believe these claims are without merit, these and any other intellectual
property claims, with or without merit, could be time-consuming and expensive to
litigate or settle, could require us to enter into costly royalty arrangements,
could divert management attention from administering our business and could
preclude us from conducting our business.

                                       14
<PAGE>   166

WE MAY BE SUBJECT TO LIABILITY FOR TRANSMITTING INFORMATION, AND OUR INSURANCE
COVERAGE MAY BE INADEQUATE TO PROTECT US FROM THIS LIABILITY.

     We may be subject to claims relating to information transmitted over
systems we develop or operate. These claims could take the form of lawsuits for
defamation, negligence, copyright or trademark infringement or other actions
based on the nature and content of the materials. Although we carry general
liability insurance, our insurance may not cover potential claims of this type
or may not be adequate to cover all costs incurred in defense of potential
claims or to indemnify us for all liability that may be imposed.

DISRUPTION OF OUR SERVICES DUE TO ACCIDENTAL OR INTENTIONAL SECURITY BREACHES
MAY HARM OUR REPUTATION CAUSING A LOSS OF SALES AND COULD INCREASE OUR EXPENSES.

     A significant barrier to the growth of wireless data services or
transactions on the Internet or by other electronic means has been the need for
secure transmission of confidential information. Our systems could be disrupted
by unauthorized access, computer viruses and other accidental or intentional
actions. We may incur significant costs to protect against the threat of
security breaches or to alleviate problems caused by such breaches. If a third
party were able to misappropriate our users' personal or proprietary information
or credit card information, we could be subject to claims, litigation or other
potential liabilities that could materially adversely impact our revenue and may
result in the loss of customers.

ANY TYPE OF SYSTEMS FAILURE COULD REDUCE SALES, INCREASE COSTS OR RESULT IN
CLAIMS OF LIABILITY.

     Our existing wireless data services -- TradeRunner, Reuters MarketClip and
its predecessor AirBroker and the Mobeo services -- are dependent on real-time,
continuous feeds from Reuters Selectfeed Plus and others. The ability of our
subscribers to make securities trades through Morgan Stanley Dean Witter Online
requires timely and uninterrupted connections with our wireless network
carriers. Any disruption from our satellite feeds or backup landline feeds could
result in delays in our subscribers' ability to receive information or execute
trades. There can be no assurance that our systems will operate appropriately if
we experience a hardware or software failure or if there is an earthquake, fire
or other natural disaster, a power or telecommunications failure, intentional
disruptions of service by third parties, an act of God or an act of war. A
failure in our systems could cause delays in transmitting data, and as a result
we may lose customers or face litigation that could involve material costs and
distract management from operating our business.

OUR ABILITY TO SELL NEW AND EXISTING SERVICES AT A PROFIT COULD BE IMPAIRED BY
COMPETITORS.

     Intense competition could develop in the market for services we offer. We
developed our software using standard industry development tools. Many of our
agreements with wireless carriers, wireless handheld device manufacturers and
data providers are non-exclusive. Our competitors could develop and use the same
products and services in competition with us. With time and capital, it would be
possible for competitors to replicate our services. Our competitors could
include wireless network carriers such as AT&T Wireless Services and Bell
Atlantic Mobile, software developers such as Microsoft Corporation, 724
Solutions Inc. and Phone.com and systems integrators such as International
Business Machines Corporation. Many of our competitors have significantly
greater resources than we do. Furthermore, competitors may develop a different
approach to marketing the services we provide in which subscribers may not be
required to pay for the information provided by our services. Competition could
reduce our market share or force us to lower prices to unprofitable levels.
Additional information regarding our competition is described under
"Business -- Competition" on page 54.

WE MAY LOSE THE OPPORTUNITY TO PURSUE DESIRABLE PROJECTS TO OMNISKY AND THE
COMPANY WE PLAN TO FORM WITH REUTERS.

     David S. Oros, our chairman, chief executive officer and president, also
serves as a director of OmniSky and Janice M. Roberts, one of our directors, is
also a director of OmniSky. OmniSky is a

                                       15
<PAGE>   167

separate business in which we have an equity interest that is developing
applications for wireless access to the Internet and related applications such
as wireless e-mail. David S. Oros will serve as chairman and interim chief
executive officer of our European strategic alliance with Reuters. This company
will be a separate business that will provide wireless data applications in
Europe. Mr. Oros and Ms. Roberts may learn of business opportunities that are
appropriate for OmniSky and us, and Mr. Oros may learn of business opportunities
that are appropriate for our pending strategic alliance with Reuters and us, and
Mr. Oros and Ms. Roberts may not be required to make those opportunities
available to us. If OmniSky or our strategic alliance with Reuters pursue
opportunities that we would have an interest in pursuing, our business may fail
to grow or our existing business may suffer. Mr. Oros and Ms. Roberts may also
have other conflicts of interest with Aether because of their positions with
OmniSky, and OmniSky's contractual relationships with Aether and 3Com. Mr. Oros
may also have other conflicts of interest with Aether because of his position
with the strategic alliance with Reuters and its contractual relationships with
Aether. We describe those contracts in "Transactions between Aether and its
Officers, Directors or Significant Stockholders -- OmniSky" on page 70.

AN INTERRUPTION IN THE SUPPLY OF PRODUCTS AND SERVICES THAT WE OBTAIN FROM THIRD
PARTIES COULD CAUSE A DECLINE IN SALES OF OUR SERVICES, AND PRODUCTS WE PURCHASE
TO AVOID SHORTAGES MAY BECOME OBSOLETE BEFORE WE CAN USE THEM.

     In designing, developing and supporting our wireless data services, we rely
on wireless carriers, wireless handheld device manufacturers, content providers
and software providers. These suppliers may experience difficulty in supplying
us products or services sufficient to meet our needs or they may terminate or
fail to renew contracts for supplying us these products or services on terms we
find acceptable. Any significant interruption in the supply of any of these
products or services could cause a decline in sales of our services unless and
until we are able to replace the functionality provided by these products and
services. Specifically, Novatel Wireless and Sierra Wireless Inc. are our only
suppliers of wireless modems, which are an integral hardware component of our
services. It can be difficult to obtain these wireless modems and their parts.
Although we have purchased a large supply of these modems, they may become
obsolete before we are able to use them. We also depend on third parties to
deliver and support reliable products, enhance their current products, develop
new products on a timely and cost-effective basis and respond to emerging
industry standards and other technological changes. In addition, we rely on the
ability of our content providers -- Reuters, the New York Stock Exchange, Inc.,
the Chicago Board of Trade, the Nasdaq Stock Market, Inc. and the Options Price
Reporting Authority -- to continue to provide us with uninterrupted access to
the news and financial information we provide to our customers. The failure of
third parties to meet these criteria, or their refusal or failure to deliver the
information for whatever reason, could materially harm our business.

OUR SALES CYCLE IS LONG, AND OUR STOCK PRICE COULD DECLINE IF SALES ARE DELAYED
OR CANCELLED.

     Quarterly fluctuations in our operating performance are exacerbated by the
length of time between our first contact with a business customer and the first
revenue from sales of services to that customer or end users. Because our
services represent a significant investment for our business customers, we spend
a substantial amount of time educating them regarding the use and benefits of
our services and they, in turn, spend a substantial amount of time performing
internal reviews and obtaining capital expenditure approvals before purchasing
our services. As much as a year may elapse between the time we approach a
business customer and the time we begin to deliver services to a customer or end
user. Any delay in sales of our services could cause our quarterly operating
results to vary significantly from projected results, which could cause our
stock price to decline. In addition, we may spend a significant amount of time
and money on a potential customer that ultimately does not purchase our
services. A decline in the price of our common stock would likely affect the
price of our notes.

                                       16
<PAGE>   168

OUR SALES OF FINANCIAL DATA AND TRADING SERVICES COULD GO DOWN IF THERE IS A
DECLINE IN SECURITIES TRADING.

     In 1999, we earned 59.0% (or 69.5% on a pro forma basis giving effect to
the acquisitions of Mobeo and LocusOne and the pending acquisition of Riverbed)
of our revenue from services that provide financial information and wireless
trading capability. If there is a prolonged decline in the overall level of
securities trading, or online trading in particular, our operating results may
decline. A decline in securities trading may result from:

     - loss of confidence in the reliability or security of online trading
       systems;

     - government regulation of the securities industry or online trading; or

     - a downturn in the stock market.

OUR SOFTWARE MAY CONTAIN DEFECTS OR ERRORS, AND OUR SALES COULD GO DOWN IF THIS
INJURES OUR REPUTATION OR DELAYS SHIPMENTS OF OUR SOFTWARE.

     The AIM package of wireless messaging and software development tools we
develop, and the ScoutWare family of software products we will own at the
closing of the Riverbed acquisition, are complex and must meet the stringent
technical requirements of our customers. We must develop our services quickly to
keep pace with the rapidly changing software and telecommunications markets.
Software as complex as ours is likely to contain undetected errors or defects,
especially when first introduced or when new versions are released. Our software
may not be free from errors or defects after delivery to customers have begun,
which could result in the rejection of our software or services, damage to our
reputation, lost revenue, diverted development resources and increased service
and warranty costs.

UNDISCOVERED YEAR 2000-RELATED COMPUTER PROBLEMS COULD DISRUPT OUR OPERATIONS.

     We believe that software that is incorporated in our products and services
is year 2000 compliant. When the century changed, we experienced no disruption
to our business operations and no product failures as a result of year 2000
compliance issues or otherwise. We may face claims, however, for undiscovered
year 2000 errors in our own products or for year 2000 issues arising from
third-party products that we integrate into our products and services or with
which our systems and products exchange data. If our suppliers, vendors or
distributors fail to timely and completely correct their own year 2000 software,
firmware and hardware problems, or if any of them convert to a system that is
incompatible with our systems, our ability to deliver our products and services
could be disrupted.

THE STOCKHOLDER AGREEMENT AMONG OUR MAJOR STOCKHOLDERS WILL HAVE THE EFFECT OF
ALLOWING THEM TO CONTROL EIGHT OF OUR TWELVE DIRECTORS, WHICH WILL LIMIT THE
ABILITY OF NEW INVESTORS TO INFLUENCE CONTROL OF AETHER.

     NexGen Technologies, L.L.C., Telcom-ATI Investors, L.L.C., Reuters
MarketClip Holdings Sarl, a subsidiary of Reuters Group PLC, and 3Com -- who
together will hold 55.1% of the shares of common stock outstanding following
completion of this offering -- entered into a stockholder agreement that governs
voting for our directors. The agreement provides that each party will vote all
of its shares for two directors nominated by NexGen, two directors nominated by
Telcom-ATI Investors, two directors nominated jointly by NexGen and Telcom-ATI
Investors and one director nominated by each of Reuters and 3Com. As a result,
eight directors of our board are effectively chosen by these major stockholders.
As we currently have authorized only 12 directors, the voting rights of our
stockholders other than these major stockholders effectively apply to only four
of our directors. In addition to its effect on the voting rights of our new
investors, the stockholder agreement could have the effect of delaying or
preventing a change in control.

WE MAY NEED ADDITIONAL CAPITAL AND WE MAY NOT BE ABLE TO OBTAIN IT, WHICH COULD
PREVENT US FROM CARRYING OUT OUR BUSINESS STRATEGY.

     We currently anticipate that our available cash resources combined with the
net proceeds from this offering and the concurrent common stock offering will be
sufficient to fund our operating needs for at

                                       17
<PAGE>   169

least the next 12 months, including the expansion of our sales and marketing
program and any acquisitions we may pursue in the next 12 months. Thereafter, we
expect to require additional financing in an amount that we cannot determine at
this time. We do not have any bank credit facility or other working capital
credit line under which we may borrow funds for working capital or other general
corporate purposes. If our plans or assumptions change or are inaccurate, we may
be required to seek capital sooner than anticipated. We may need to raise funds
through public or private debt or equity financings.

     If funds are raised through the issuance of equity securities, the
percentage ownership of our then-current stockholders may be reduced and the
holders of new equity securities may have rights, preferences or privileges
senior to those of the holders of our common stock. If additional funds are
raised through a bank credit facility or the issuance of debt securities, the
holder of this indebtedness would have rights senior to the rights of the
holders of our common stock and the terms of this indebtedness could impose
restrictions on our operations. If we need to raise additional funds, we may not
be able to do so on terms favorable to us, or at all. If we cannot raise
adequate funds on acceptable terms, we may not be able to continue to fund our
operations.

     We may not be able to complete the proposed common stock offering being
conducted concurrently with this offering. Failure to complete the common stock
offering may increase our need for financing.

NEW LAWS AND REGULATIONS THAT IMPACT OUR INDUSTRY COULD INCREASE OUR COSTS OR
REDUCE OUR OPPORTUNITIES TO EARN REVENUE.

     We are not currently subject to direct regulation by the Federal
Communications Commission or any other governmental agency, other than
regulations applicable to businesses in general. However, in the future, we may
become subject to regulation by the FCC or another regulatory agency. In
addition, the wireless carriers who supply us airtime are subject to regulation
by the FCC and regulations that affect them could increase our costs or reduce
our ability to continue selling and supporting our services.

OUR STOCK PRICE, LIKE THAT OF MANY TECHNOLOGY COMPANIES, HAS BEEN, AND MAY
CONTINUE TO BE, VOLATILE.

     The market price of our common stock has been highly volatile and is likely
to continue to be highly volatile. The trading price of our common stock has
increased significantly from our initial offering price of $16.00 per share on
October 20, 1999. We are involved in a highly visible, rapidly changing industry
and stock prices in our and similar industries have risen and fallen in response
to a variety of factors, including:

     - announcements of new wireless data communications technologies and new
       providers of wireless data communications;

     - acquisitions of or strategic alliances among providers of wireless data
       communications;

     - changes in recommendations by securities analysts regarding the results
       or prospects of providers of wireless data communications; and

     - changes in investor perceptions of the acceptance or profitability of
       wireless data communications.

Fluctuations in the price of our common stock are likely to affect the price of
our notes.

WE HAVE ANTI-TAKEOVER DEFENSES THAT COULD DELAY OR PREVENT AN ACQUISITION AND
COULD ADVERSELY AFFECT THE PRICE OF OUR COMMON STOCK.

     Provisions of our certificate of incorporation and bylaws and provisions of
Delaware law could delay, defer or prevent an acquisition or change of control
of Aether or otherwise adversely affect the price of our common stock. For
example, our bylaws limit the ability of stockholders to call a special meeting.
Our certificate of incorporation also permits our board to issue shares of
preferred stock without stockholder approval which means that the board could
issue shares with special voting rights or other provisions that could deter a
takeover. In addition to delaying or preventing an acquisition, the issuance of
a substantial number of preferred shares could adversely affect the price of the
common stock. A decline in the price of our common stock would likely affect the
price of our notes. Please refer to "Description of Capital Stock" on page 90
for a more detailed discussion of these provisions.

                                       18
<PAGE>   170

SHARES ELIGIBLE FOR FUTURE SALE BY OUR CURRENT STOCKHOLDERS MAY DEPRESS OUR
SHARE PRICE.

     After this offering, we will have outstanding 34,509,687 shares of common
stock, including the 4,537,286 shares to be issued to former shareholders of
Riverbed, assuming the completion of the concurrent common stock offering. Sales
of a substantial number of our shares of common stock in the public market
following this offering -- or the expectation of such sales -- could cause the
market price of our common stock to drop. All the shares sold in the concurrent
common stock offering will be, and the shares sold in our initial public
offering are, freely tradable. An additional 24,114,750 shares will be available
for sale in the public markets as follows:

<TABLE>
<CAPTION>
               DATE OF AVAILABILITY FOR SALE                  NUMBER OF SHARES
               -----------------------------                  ----------------
<S>                                                           <C>
               (90 days after the date of this
  prospectus)...............................................         19,250
October 26, 2000............................................     19,671,646
At various times thereafter upon the expiration of one-year
  holding periods...........................................      4,423,854
</TABLE>

     Of these shares, 24,095,500 shares are subject to a limitation on the
number of shares that can be sold in any three-month period. We have agreed,
however, to register the resale of substantially all of these shares upon demand
beginning October 27, 2000.

     We filed a registration statement to register all shares of common stock
that were issued to our employees under our equity incentive plan and intend to
file future registration statements. Shares issued upon exercise of stock
options will be eligible for resale in the public market without restriction. As
of February 15, 2000, options and warrants to purchase 4,012,574 shares of our
common stock were issued and outstanding and we were obligated to issue options
for an additional 862,480 shares in connection with our pending acquisition of
Riverbed. A decline in the price of our common stock would likely affect the
price of our notes.

DEBT SERVICE OBLIGATIONS MAY ADVERSELY AFFECT OUR CASH FLOW.

     If this offering is completed as planned, we will have substantial amounts
of outstanding indebtedness, primarily consisting of the notes. As a result of
this indebtedness, we will be obligated to make principal and interest payments.
There is the possibility that we may be unable to generate cash sufficient to
pay the principal of, interest on and other amounts due in respect of our
indebtedness when due. We may also obtain additional long-term debt and working
capital lines of credit to meet future financing needs. There can be no
assurance that additional financing arrangements will be available on
commercially reasonable terms or at all.

WE MAY HAVE CONTINGENT LIABILITY ARISING OUT OF A POSSIBLE VIOLATION OF THE
SECURITIES ACT OF 1933 IN CONNECTION WITH A LETTER SENT TO EMPLOYEES IN THE
DIRECTED SHARE PROGRAM AT THE TIME OF OUR INITIAL PUBLIC OFFERING.

     As part of our initial public offering in October 1999, we decided that
each of our employees, officers and directors should have the opportunity to
purchase up to 2,000 shares of common stock as part of a directed share program,
on the same terms as all other shares offered by the prospectus, but that each
person could choose to direct all or a part of the 2,000 shares to members of
his or her immediate family. In order to coordinate this program, we sent a
letter to approximately 90 employees, officers and directors we had designated
as potential offerees of up to 390,000 shares of common stock and asked them to
provide us with information for mailing purposes, including an estimate of the
number of shares that they would want to be given the opportunity to purchase
and to have their immediate family members provide the same information. Our
letter was not accompanied by a preliminary prospectus and may have constituted
a prospectus that does not meet the requirements of the Securities Act of 1933.
If the mailing of these original materials did constitute a violation of the
Securities Act of 1933, the recipients of the letter who purchased common stock
in our initial public offering and continue to own those shares could have the
right until October 26, 2000 to obtain recovery of the consideration paid in
connection with their

                                       19
<PAGE>   171

purchase of common stock or, if they had already sold the stock, sue us for
damages resulting from their purchase of common stock. If all of the recipients
of the letter still hold shares they purchased in the initial public offering,
these refunds or damages could total up to approximately $6.2 million, based on
the initial public offering price of $16.00 per share, in the event that
investors suffer a total loss of their investment before they sold the shares or
the relevant limitations period expired and seek refunds or damages. If this
were to occur, our business, results of operations and financial condition could
suffer.

YOUR RIGHT TO RECEIVE PAYMENTS ON THE NOTES IS SUBORDINATED TO ALL OF OUR
EXISTING AND FUTURE SENIOR INDEBTEDNESS AND THE NOTES ARE EFFECTIVELY
SUBORDINATED TO INDEBTEDNESS OF OUR SUBSIDIARIES.

     The notes will be unsecured obligations and will be subordinated in right
of payment, as provided in the indenture under which they are issued, to the
prior payment in full in cash or other payment satisfactory to holders of senior
indebtedness of all our existing and future senior indebtedness. Senior
indebtedness is defined to include, among other things, all indebtedness for
money borrowed and indebtedness evidenced by securities, debentures, bonds or
other similar instruments. Senior indebtedness does not include indebtedness
that is expressly junior in right of payment to the notes or ranks pari passu in
right of payment to the notes. As of February 15, 2000, we had approximately
$19.0 million of senior indebtedness outstanding which we incurred in connection
with our acquisition of LocusOne. The notes will also be subordinate to
approximately $360,000 of senior indebtedness which will be incurred by one of
our subsidiaries in connection with our acquisition of Riverbed. The terms of
the notes do not limit the amount of additional indebtedness, including senior
indebtedness, which we can create, incur, assume or guarantee. Upon any
distribution of our assets upon any insolvency, dissolution or reorganization,
the payment of the principal of and interest on the notes will be subordinated
to the extent provided in the indenture to the prior payment in full of all of
our senior indebtedness, and there may not be sufficient assets remaining to pay
amounts due on any or all of the notes then outstanding.

     The notes are effectively subordinated to all existing and future
liabilities of our subsidiaries. Any right of ours to receive assets of any of
our subsidiaries upon their liquidation or reorganization, and the consequent
right of the holders of the notes to participate in those assets, will be
subject to the claims of that subsidiary's creditors. If we ourselves are a
creditor of that subsidiary, our claims would still be subordinate to any
security interests in the assets of that subsidiary and any senior indebtedness
of that subsidiary.

WE MAY NOT BE ABLE TO SATISFY A CHANGE OF CONTROL OFFER.

     The indenture governing the notes contains provisions that apply to a
change of control of our company. If someone triggers a change of control as
defined in the indenture, we must offer to purchase those notes with cash, or at
our option with our common stock, subject to the terms and conditions of the
indenture. If we have to make that offer, we cannot be sure that we will have
enough funds or common stock to pay for all the notes that the holders could
tender.

OUR NOTES HAVE NEVER BEEN PUBLICLY TRADED SO WE CANNOT PREDICT THE EXTENT TO
WHICH A TRADING MARKET WILL DEVELOP FOR OUR NOTES.

     There has not been a public market for our notes. We cannot predict the
extent to which a trading market will develop or how liquid that market might
become, which could limit the liquidity of your investment in the notes.

OUR CONCURRENT STOCK OFFERING MAY NOT BE COMPLETED, IN WHICH CASE WE MAY NEED
ADDITIONAL FINANCING TO FUND THE INTEREST PAYMENTS ON THE NOTES.

     This offering is not contingent on the completion of the common stock
offering. We cannot assure you that our concurrent common stock offering will be
completed. If the concurrent common stock offering is not completed, then we may
need additional financing to fund the interest payments on the notes.

                                       20
<PAGE>   172

                           FORWARD-LOOKING STATEMENTS

     This prospectus includes forward-looking statements within the meaning of
Section 27A of the Securities Act and Section 21E of the Securities Exchange
Act. These include projections about the industry contained on pages 38 to 39.
We have based these forward-looking statements on our current expectations and
projections about future events. In some cases, you can identify forward-looking
statements by terminology such as "may," "will," "should," "could," "pending,"
"potential," "continue," "expects," "anticipates," "intends," "plans,"
"believes," "predicts," "estimates" and similar expressions, although not all
forward-looking statements are identified by these words. These forward-looking
statements are subject to a number of risks, uncertainties and assumptions about
Aether, including those we describe in the "Risk Factors" section of this
prospectus. In light of these risks, uncertainties and assumptions, the
forward-looking events discussed in this prospectus might not occur. We
undertake no obligation to publicly update or revise any forward-looking
statements, whether as a result of new information, future events or otherwise.

     We use market data and industry forecasts and projections throughout this
prospectus, which we have obtained from internal surveys, market research,
publicly available information and industry publications. Industry publications
generally state that the information they provide has been obtained from sources
believed to be reliable, but that the accuracy and completeness of such
information is not guaranteed. The forecasts and projections are based on
industry surveys and the preparers' experience in the industry and there is no
assurance that any of the projected amounts will be achieved. Similarly, we
believe that the surveys and market research we or others have performed are
reliable, but we have not independently verified this information. Neither we
nor any of the underwriters represents that any such information is accurate.

                                       21
<PAGE>   173

                                USE OF PROCEEDS

     The net proceeds to us from this convertible notes offering are expected to
be approximately $192.8 million ($221.9 million if the underwriters'
over-allotment option is exercised in full) after deduction of estimated
underwriting discounts and commissions and estimated offering expenses payable
by us. We also expect to receive approximately $452.5 million in net proceeds
from the sale of 2,346,219 shares of common stock, assuming an offering price of
$203, by Aether in our concurrent offering ($483.4 million if the underwriters'
over-allotment option is exercised in full) after deduction of estimated
underwriting discounts and commissions and estimated offering expenses payable
by us and the exercise of options to purchase 145,000 shares by the selling
stockholders. We will not receive any proceeds from the 653,781 shares sold by
selling stockholders in the offering.

     We currently intend to use $100 million of the proceeds of this offering
and the concurrent common stock offering to fund our European strategic alliance
with Reuters, $19 million to repay indebtedness incurred in connection with the
LocusOne acquisition, $17 million to acquire 9.9% of the stock of Metrocall, $10
million to acquire our 27.5% interest in Inciscent and an estimated $25 million
to fund sales and marketing activities. We have not determined the use of the
remaining proceeds of this offering and the concurrent common stock offering,
but we expect to use some portion of the proceeds to provide the cash portion of
acquisitions and strategic investments we may identify in the future that
advance our strategy.

     Pending these uses, the net proceeds of these offerings will be invested in
short-term, investment grade, interest-bearing instruments.

                          PRICE RANGE OF COMMON STOCK

     Our common stock has been quoted on the Nasdaq National Market under the
symbol "AETH" since our initial public offering on October 20, 1999. Prior to
that time, there was no public market for the common stock. The following table
sets forth, for the periods indicated, the high and low prices per share of the
common stock as reported on the Nasdaq National Market.

<TABLE>
<CAPTION>
                                                              HIGH    LOW
                                                              ----    ---
<S>                                                           <C>     <C>
1999
Fourth Quarter (since October 20, 1999).....................  $ 89 3/8 $41 1/8
2000
First Quarter (through February 18, 2000)...................  $250    $73
</TABLE>

     On February 18, 2000 the reported last sale price of the common stock on
the Nasdaq National Market was $203. As of February 17, 2000 there were
approximately 19 holders of record of our common stock.

                                DIVIDEND POLICY

     We have never declared or paid any cash dividends on our capital stock nor,
when we were organized as a limited liability company, have we made any
distributions to our members. We currently intend to retain earnings, if any, to
support the development of our business and do not anticipate paying cash
dividends in the foreseeable future. Payment of future dividends, if any, will
be at the discretion of our board of directors after taking into account factors
such as our financial condition, operating results and current and anticipated
cash needs.

                                       22
<PAGE>   174

                              CONCURRENT OFFERING

     Concurrently with our offering of notes, we are offering by means of a
separate prospectus 2,346,219 shares of our common stock and the Aether
stockholders identified in the prospectus for the common stock offering are
offering 653,781 shares of our common stock. The completion of the common stock
offering is not a condition to the completion of this offering.

                                       23
<PAGE>   175

                                 CAPITALIZATION

     The table below sets forth the following information as of December 31,
1999:

          - our actual capitalization;

          - our pro forma capitalization giving effect to the acquisition of
            LocusOne and the pending acquisition of Riverbed as if completed on
            December 31, 1999;

          - our pro forma capitalization giving effect to the acquisitions
            described above and the issuance and sale of $200 million of our
                 % convertible subordinated notes due 2005 in this offering; and

        - our pro forma capitalization giving effect to the acquisitions
          described above, the sale of notes in this offering and the sale of
          2,346,219 shares of common stock in the concurrent offering and the
          exercise of options to purchase 145,000 shares by the selling
          stockholders.

     The table below includes deductions for estimated underwriting discounts
and commissions, and for estimated offering expenses in connection with this
offering and the concurrent offering of common stock as applicable.

     Actual common stock data are as of December 31, 1999 and exclude:

          - 3,620,838 shares issuable upon exercise of options to purchase
            shares of common stock issued, or to be issued, in connection with
            our pending acquisition of Riverbed, under our equity incentive plan
            at a weighted average exercise price of $6.76 per share;

          - 1,175,000 shares issuable upon exercise of warrants exercisable at a
            weighted average exercise price of $1.96 per share; and

          - 893,665 shares of common stock issuable upon exercise of warrants
            with an exercise price of $.01 per share.

     This table should be read in conjunction with our consolidated financial
statements and the notes thereto and "Management's Discussion and Analysis of
Financial Condition and Results of Operations" beginning on page 28. Details
regarding pro forma adjustments are set forth in the Unaudited Pro Forma
Condensed Consolidated Financial Information beginning on page F-44.

                                       24
<PAGE>   176

<TABLE>
<CAPTION>
                                                                AS OF DECEMBER 31, 1999
                                   ----------------------------------------------------------------------------------
                                                                               PRO FORMA
                                                  -------------------------------------------------------------------
                                                                                                    ACQUISITIONS,
                                                                                                  CONVERTIBLE NOTES
                                                                        ACQUISITIONS AND          AND COMMON STOCK
                                      ACTUAL       ACQUISITIONS    CONVERTIBLE NOTES OFFERING       OFFERINGS(1)
                                   ------------   --------------   --------------------------   ---------------------
<S>                                <C>            <C>              <C>                          <C>
Notes payable, current...........  $         --   $   19,095,600         $      120,578            $      120,578
Notes payable long term..........            --          241,155                241,155                   241,155
Convertible subordinated notes...            --               --            200,000,000               200,000,000
                                   ------------   --------------         --------------            --------------
         Total debt..............            --       19,336,755            200,361,733               200,361,733
                                   ------------   --------------         --------------            --------------
Stockholders' equity:
  Preferred stock, $0.01 par
    value; 1,000,000 shares
    authorized; 0 shares issued
    and outstanding..............            --               --                     --                        --
  Common stock, $0.01 par value;
    75,000,000 shares authorized;
    shares issued and
    outstanding: actual,
    27,154,398; acquisitions,
    31,691,684; acquisitions and
    convertible notes offering,
    31,691,684; and acquisitions,
    convertible notes and common
    stock offering, 34,182,903...       271,543          316,916                316,916                   341,829
  Additional paid-in-capital.....   120,892,478    1,241,650,105          1,241,650,105             1,694,169,382
  Accumulated deficit............   (22,613,640)     (22,613,640)           (22,613,640)              (22,613,640)
  Notes receivable from
    stockholder..................      (137,879)        (137,879)              (137,879)                 (137,879)
  Unrealized loss on investments
    available for sale...........       (70,069)         (70,069)               (70,069)                  (70,069)
                                   ------------   --------------         --------------            --------------
         Total stockholders'
           equity................    98,342,433    1,219,145,433          1,219,145,433             1,671,689,623
                                   ------------   --------------         --------------            --------------
         Total capitalization....  $ 98,342,433   $1,238,482,188         $1,419,507,166            $1,872,051,356
                                   ============   ==============         ==============            ==============
</TABLE>

- ---------------

(1) Completion of the common stock offering is not a condition to the completion
    of this offering.

                                       25
<PAGE>   177

                      SELECTED CONSOLIDATED FINANCIAL DATA
               (in thousands, except share and per share amounts)

     The table that follows presents portions of our consolidated financial
statements and is not complete. You should read the following selected
consolidated financial data together with our consolidated financial statements
and related notes and with "Management's Discussion and Analysis of Financial
Condition and Results of Operations" included elsewhere in this prospectus. The
consolidated statement of operations data for the years ended December 31, 1997,
1998 and 1999, and the consolidated balance sheet data as of December 31, 1998
and 1999, are derived from our consolidated financial statements, which have
been audited by KPMG LLP, independent auditors, and which are included in this
prospectus beginning on page F-1. The consolidated statement of operations data
for the year ended December 31, 1996 and the consolidated balance sheet data as
of December 31, 1996 and 1997 are derived from audited financial statements that
do not appear in this prospectus. The historical results presented below are not
necessarily indicative of the results to be expected for any future fiscal year.
See "Management's Discussion and Analysis of Financial Condition and Results of
Operations" beginning on page 28.

     The pro forma consolidated financial information gives effect to (i) the
Mobeo and LocusOne acquisitions and the pending acquisition of Riverbed, (ii)
the sale of $200 million of our convertible notes in this offering and the
application of the net proceeds as described in "Use of Proceeds" on page 22 and
(iii) the concurrent offering of common stock and the application of the net
proceeds as described in "Use of Proceeds" on page 22. The pro forma net loss
per share information gives effect to our conversion from a limited liability
company to a corporation immediately prior to our initial public offering.

     We have provided the pro forma consolidated financial information for
informational purposes only and you should not assume that our results would
actually have been as shown if we had acquired Mobeo, LocusOne and Riverbed or
completed the offerings on the assumed dates, or that the information projects
what our results will be as a result of the acquisitions or if we complete the
offerings. The pro forma consolidated statement of operations information
assumes that the transactions occurred on January 1, 1999, and the pro forma
consolidated balance sheet information assumes that the transactions occurred on
December 31, 1999. See our, Mobeo's and Riverbed's financial statements and
notes to those statements included in this prospectus beginning on page F-1.

                                       26
<PAGE>   178

<TABLE>
<CAPTION>
                                                                   YEAR ENDED DECEMBER 31,
                            -----------------------------------------------------------------------------------------------------
                                                                                                 1999 PRO FORMA
                                                                                -------------------------------------------------
                                                                                                                  ACQUISITIONS,
                                                                                                ACQUISITIONS    CONVERTIBLE NOTES
                                               HISTORICAL                                           AND                AND
                            -------------------------------------------------                   CONVERTIBLE       COMMON STOCK
                               1996         1997         1998         1999      ACQUISITIONS   NOTES OFFERING       OFFERINGS
                            ----------   ----------   ----------   ----------   ------------   --------------   -----------------
<S>                         <C>          <C>          <C>          <C>          <C>            <C>              <C>
CONSOLIDATED STATEMENT OF
  OPERATIONS DATA:
Revenue:
  Subscriber revenue......  $       --   $      161   $      549   $    3,732    $   11,200      $   11,200        $   11,200
  Engineering services
    revenue...............       1,355        1,625          963        2,594         2,594           2,594             2,594
  Software and related
    services revenue......          --           --           --           --         2,317           2,317             2,317
                            ----------   ----------   ----------   ----------    ----------      ----------        ----------
      Total revenue.......       1,355        1,786        1,512        6,326        16,111          16,111            16,111
  Cost of subscriber
    revenue...............          --          447          797        2,110         4,639           4,639             4,639
  Cost of engineering
    services revenue......       1,007          846          304        1,366         1,366           1,366             1,366
  Cost of software and
    related services
    revenue...............          --           --           --           --         1,541           1,541             1,541
                            ----------   ----------   ----------   ----------    ----------      ----------        ----------
      Total cost of
         revenue..........       1,007        1,293        1,101        3,476         7,546           7,546             7,546
                            ----------   ----------   ----------   ----------    ----------      ----------        ----------
      Gross profit........         348          493          411        2,850         8,565           8,565             8,565
Operating expenses:
  Research and
    development...........         161          734        1,267        2,614         5,481           5,481             5,481
  General and
    administrative........         395        1,505        2,773        5,891         8,913           8,913             8,913
  Selling and marketing...          --          333          840        2,095         6,831           6,831             6,831
  Depreciation and
    amortization..........          45          189          265        1,089       386,351         386,351           386,351
  Option and warrant
    expense...............          --           40           33       19,198        33,524          33,524            33,524
                            ----------   ----------   ----------   ----------    ----------      ----------        ----------
    Total operating
      expenses............         601        2,801        5,178       30,887       441,100         441,100           441,100
                            ----------   ----------   ----------   ----------    ----------      ----------        ----------
Operating loss............        (253)      (2,308)      (4,767)     (28,037)     (432,535)       (432,535)         (432,535)
Interest income, net......           8            7           70          (60)          108         (14,332)          (14,332)
Equity in losses of
  investments.............        (172)        (144)          --       (2,425)       (2,425)         (2,425)           (2,425)
Realized gain (loss) on
  sale of investments.....          --         (302)           4         (169)         (169)           (169)             (169)
                            ----------   ----------   ----------   ----------    ----------      ----------        ----------
Net loss..................  $     (417)  $   (2,747)  $   (4,693)  $  (30,691)   $ (435,021)     $ (449,461)       $ (449,461)
                            ==========   ==========   ==========   ==========    ==========      ==========        ==========
Ratio of earnings to fixed
  charges(1)..............          --           --           --           --                                              --
Pro forma net loss per
  share-basic and
  diluted.................  $    (0.04)  $    (0.22)  $    (0.29)  $    (1.45)   $   (16.90)     $   (17.45)       $   (15.92)
                            ==========   ==========   ==========   ==========    ==========      ==========        ==========
Pro forma weighted average
  shares used in computing
  net loss per share-basic
  and diluted.............  10,554,795   12,655,901   15,916,383   21,207,225    25,744,511      25,744,511        28,235,730
                            ==========   ==========   ==========   ==========    ==========      ==========        ==========
</TABLE>
<TABLE>
<CAPTION>

                             1996        1997         1998         1999
                          ----------   ---------   ----------   ----------
<S>                       <C>          <C>         <C>          <C>
CONSOLIDATED BALANCE
  SHEET DATA:
  Cash and cash
    equivalents.........  $       51   $     132   $    1,755   $   78,542
  Working capital
    (deficit)...........         181        (323)       7,519       83,128
  Total assets..........       1,269         822        8,765      102,534
  Total debt............          --         150           --           --
  Members' capital......       1,101          74        8,030           --
  Stockholders'
    equity..............          --          --           --       98,342

<CAPTION>
                                            AS OF DECEMBER 31, 1999 PRO FORMA
                          ---------------------------------------------------------------------
                                                                      ACQUISITIONS, CONVERTIBLE
                                              ACQUISITIONS AND            NOTES AND COMMON
                          ACQUISITIONS   CONVERTIBLE NOTES OFFERING        STOCK OFFERINGS
                          ------------   --------------------------   -------------------------
<S>                       <C>            <C>                          <C>
CONSOLIDATED BALANCE
  SHEET DATA:
  Cash and cash
    equivalents.........   $   47,719            $   94,544                  $  547,088
  Working capital
    (deficit)...........       37,064               102,864                     555,408
  Total assets..........    1,244,067             1,425,092                   1,877,637
  Total debt............       19,337               200,362                     200,362
  Members' capital......           --                    --                          --
  Stockholders'
    equity..............    1,219,145             1,219,145                   1,671,690
</TABLE>

- ------------------------
(1) Earnings were insufficient to cover fixed charges by $417, $2,747, $4,693
    and $30,691 for years 1996, 1997, 1998 and 1999, respectively, and $449,461
    pro forma for 1999.

                                       27
<PAGE>   179

                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS

     You should read the following description of our financial condition and
results of operations in conjunction with the financial statements and the notes
thereto and the unaudited pro forma condensed consolidated financial information
included in this prospectus beginning on page F-1.

OVERVIEW

     Aether Systems, Inc. was originally formed as Aeros, L.L.C. in January
1996. We changed our name to Aether Technologies International, L.L.C. effective
August 1996 and to Aether Systems LLC effective September 1999. Immediately
before completing our initial public offering of common stock on October 26,
1999, the limited liability company was converted into a corporation called
Aether Systems, Inc.

     Development of our business.  From our inception until March 1997, we
primarily provided wireless engineering services, including the development of
wireless software applications for customers. In March 1997, we began offering
services that provide the users of wireless handheld devices access to real-time
financial information. During 1997, we made a strategic decision to focus a
significant portion of our engineering resources on the development of these and
other wireless data services and systems, including our AIM package of wireless
messaging software and software development tools (also known as a software
platform). This resulted in a decrease in engineering services revenue as a
percentage of total revenue and an increase in subscriber revenue as a
percentage of total revenue. We expect this trend to continue in the foreseeable
future. We also expect to derive revenue from licensing our software.

     In August 1999, we formed a new company with 3Com called OpenSky, which was
renamed OmniSky in October 1999. We formed OmniSky with 3Com to pursue
opportunities in the emerging consumer and business mass markets for wireless
e-mail, Internet access and other electronic transactions applications. As of
February 15, 2000, we owned 33% of OmniSky. OmniSky is obligated to pay us $1.50
per month per subscriber for use of our network operations center. We have the
right to offer OmniSky's services to our subscribers in exchange for a monthly
fee to OmniSky of $3 per subscriber. On November 15, 1999, OmniSky launched its
service in a limited test phase of 5,000 subscribers and in January 2000
expanded the program to up to 7,000 subscribers. As of February 16, 2000,
OmniSky had enrolled approximately 6,800 subscribers. We provide engineering
services to OmniSky under a $3 million agreement that extends through June 2000.

     On September 28, 1999, we acquired Mobeo, which provides employees and
customers of major banks and financial institutions with real-time price quotes
and news for foreign exchange, government securities and commodities markets on
wireless handheld devices.

     On February 3, 2000, we acquired LocusOne, which provides wireless data
systems to companies that distribute goods and services using their own delivery
fleets.

     On February 7, 2000, we agreed to invest $10 million to acquire a 27.5%
interest in Inciscent, a new company we formed with Metrocall, PSINet, Hicks,
Muse, Tate & Furst and other investors through which we plan to develop wireless
e-mail, Internet access and other applications for the small office and home
office market segments. As part of the investment, we also agreed to acquire
approximately 9.9% of the outstanding capital stock of Metrocall for
approximately $17 million. Under the agreement, we will grant a perpetual AIM
license to Inciscent for $1 million and perform engineering services under a $4
million contract.

     On February 8, 2000, we signed a letter of intent with Reuters to establish
a European wireless venture, which will be headquartered in the United Kingdom
and initially focused on financial markets. The letter of intent provides that
we will acquire a 60% interest in the new company for $100 million. Our letter
of intent with Reuters does not commit either us or Reuters to form the new
company and remains subject to definitive documentation and the receipt of
proceeds from this offering to fund the investment.

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<PAGE>   180

     On February 9, 2000, we entered into an agreement to acquire Riverbed,
which develops software that extends the accessibility of applications and
information from corporate networks and databases to handheld devices.

     Our subscriber and revenue information.  Our subscriber base has
historically been derived from financial data and online trading services. The
following table shows the number of subscribers to our financial data services
and online trading services as of December 31 of each of the years shown.

<TABLE>
<CAPTION>
                                                              1997   1998   1999
                                                              ----   ----   -----
<S>                                                           <C>    <C>    <C>
Financial data services.....................................  150    687    4,288
Online trading services.....................................   --     --      277
                                                              ---    ---    -----
          Total subscribers.................................  150    687    4,565
</TABLE>

     The growth in subscribers over these periods was primarily the result of
the attraction of new subscribers to our services, the introduction of new
services and, in 1999, subscribers added through our acquisition of Mobeo. In
1997 our subscriber base was comprised of users of our AirBroker service.
Reuters MarketClip was introduced in March 1998 and produced the majority of our
subscriber growth in 1998. MarketClip provides real-time wireless access to
financial data. Reuters MarketClip yearly subscriptions started to expire in
March 1999 and 77.2% of all subscribers eligible to renew during the period from
March to December 1999 renewed their contracts for an additional one-year
period. In October 1999, we introduced Morgan Stanley Dean Witter Online
TradeRunner. TradeRunner provides real-time wireless financial data and enables
subscribers to trade stocks and options using wireless handheld devices. The
introduction of online trading service subscribers was due to the launch of
TradeRunner in October 1999.

     The majority of the growth in financial data services subscribers in 1999
is attributable to the acquisition of Mobeo, which had 3,294 subscribers as of
December 31, 1999. Mobeo's subscriber base is primarily attributable to its
foreign exchange products. Mobeo had 3,339 subscribers as of December 31, 1998
and 2,811 subscribers as of December 31, 1997. The net increase in Mobeo's
subscriber base from the end of 1997 to the end of 1998 was due to new
subscriptions of 1,660 and terminations of 1,132 subscriptions. The net decrease
in subscribers from December 31, 1998 to December 31, 1999 was due to the
termination of 1,186 subscriptions and the addition of 1,124 new subscriptions.
We believe that a substantial number of Mobeo subscriber terminations and
additions is the result of changes in personnel at financial institutions whose
traders are Mobeo subscribers. We believe the decrease in new subscribers
between 1998 and 1999 was caused by a consolidation among financial institutions
and the transition associated with the sale of Mobeo and its integration into
our operations. We plan to increase sales and marketing efforts with respect to
our foreign exchange services and to bundle the services with additional
applications. We expect that growth from online trading services will exceed
growth from financial data services as we introduce new services.

     For the year ended December 31, 1999, our cost to acquire subscribers was
greater than the revenue we derived from those subscribers over the initial
one-year contract term. The cost to acquire subscribers during this period was
approximately $2.2 million and the contracts entered into during that period
provide for payments of approximately $499,000 during the one-year term of the
contracts. We expect that revenue from new customers will begin to exceed
subscriber acquisition costs when the number of subscribers increases to cover
our fixed costs. This will depend on the rate at which subscriber levels
increase, and we cannot determine when this will occur or assure you that it
will ever occur.

     We expect to derive revenue from the licensing of our AIM software platform
and the ScoutWare software suite that we will acquire upon completing our
acquisition of Riverbed. We also expect to derive licensing revenue associated
with our e-Mobile Delivery transportation logistics and delivery services. To
date, we have not received any revenue from licensing our AIM software platform.

     LocusOne's revenue primarily consists of service revenue relating to
systems integration and ongoing support, software licensing and equipment sales.
LocusOne also receives recurring revenue for use of its network operations
center, which is expected to become a higher percentage of total revenue in the
future.

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<PAGE>   181

LocusOne's customers include Physician Sales & Service, Inc., MAC Papers, Inc.,
Office Depot, Inc., NuCo2, Inc. and Suntory Water Group. These customers
accounted for a substantial majority of LocusOne's revenue in 1999.

     Riverbed's revenue primarily consists of fees generated from licensing
software and providing related services, including maintenance and technical
support, training and consulting. A substantial majority of Riverbed's 1999
revenue was received from 3Com, Extensity, Inc., Aether, Oracle and OmniSky.

     Operating losses.  Since our inception, we have invested significant
capital to build our customer service and network operations center.
Additionally, we have incurred significant operating costs to develop our AIM
software platform and other software applications and to grow our business. As a
result, we have incurred operating losses since our inception. Part of our
strategy is to continue to invest in business development, research and
development and marketing and advertising. In addition, our acquisitions of
Mobeo and LocusOne and our pending acquisition of Riverbed will result in option
and warrant expense and very significant amortization of intangible assets. As a
result, we expect to continue to incur operating losses for the foreseeable
future.

RESULTS OF OPERATIONS

     We currently derive our revenue primarily from the sale of wireless data
services and by providing wireless engineering services. Revenue from wireless
data services generally consists of:

     - a one-time, non-refundable per-subscriber activation fee, which we
       recognize upon service activation;

     - monthly per-subscriber service fees, which we recognize as services are
       provided; and

     - monthly per-subscriber exchange fees for access to financial information
       from the securities exchanges and markets, which we recognize as services
       are provided. We pay a corresponding fee to the various exchanges and
       markets on a regular basis.

We also derive revenue from providing our subscribers with the option to
purchase wireless handheld devices from us at cost, which we bill over the
initial term of the contract. Contracts with our wireless data subscribers are
generally for a one-year period and include a termination penalty if cancelled
by the subscriber before the one-year term expires. These contracts are
generally renewable at the option of the subscriber for additional one-year
periods or otherwise continue on a monthly basis until cancelled by the
subscriber. Revenue from wireless engineering services consists of amounts
billed to our customers for engineering time on an hourly basis or on a fixed
per project basis. This revenue is recognized as the work is performed. With the
acquisition of LocusOne and the pending acquisition of Riverbed, we expect to
derive revenue from software licensing, including licensing fees, maintenance
fees and support fees.

     Cost of subscriber revenue consists primarily of airtime costs, financial
data costs, wireless handheld device costs and securities exchange and market
fees. Our airtime costs are determined by agreements we have with several
wireless carriers. Typically, we have one-year contracts to buy data network
capacity either for an agreed amount of kilobytes at a flat fee or on a
cents-per-kilobyte basis. Cost of engineering services revenue consists of cash
compensation and related costs for engineers, subcontractors and other
non-reimbursed, project-related costs. With the acquisition of LocusOne and the
pending acquisition of Riverbed, we expect to incur costs relative to software
licensing, including royalty payments and personnel costs.

     Research and development expenses consist primarily of cash compensation
and related costs for engineers engaged in research and development activities
and, to a lesser extent, costs of materials relating to these activities. We
expense research and development costs as we incur them. General and
administrative expenses consist primarily of cash compensation and related costs
for general corporate and business development personnel, along with rent and
other costs. Selling and marketing expenses consist primarily of advertising and
promotions, sales and marketing personnel, travel and entertainment and other
costs.
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<PAGE>   182

     Depreciation and amortization expenses consist primarily of amortization of
intangible assets acquired in the Mobeo acquisition and depreciation expenses
arising from equipment purchased for our network operations center and other
property and equipment purchases. With the acquisition of LocusOne and the
pending acquisition of Riverbed, depreciation and amortization expenses will
consist primarily of amortization related to goodwill and other intangibles to
be recognized as a result of these acquisitions.

     Option and warrant expense consists of expenses recorded to account for the
difference, on the date of grant, between the fair market value and the exercise
price of options issued to employees and the fair value of equity-based awards
to non-employees. With the acquisition of Mobeo and LocusOne and the pending
acquisition of Riverbed, we expect to have substantial additional option and
warrant expense.

     Other income (expense) consists of interest income, interest expense,
equity in losses of our investment in OmniSky, and realized losses on our
investments.

FISCAL YEARS ENDED DECEMBER 31, 1997, 1998 AND 1999

     Subscriber revenue. Subscriber revenue of $161,400 for the year ended
December 31, 1997 is attributable to our AirBroker service, which provides
real-time financial information via cellular phones. Subscriber revenue
increased to $549,057 for the year ended December 31, 1998 primarily due to the
launch of Reuters MarketClip in March 1998. Subscriber revenue increased to $3.7
million for the year ended December 31, 1999 as a result of an increase in
MarketClip subscribers, the introduction of TradeRunner and the acquisition of
Mobeo in September 1999. Services acquired from Mobeo contributed revenue of
$2.4 million for the year ended December 31, 1999.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, subscriber revenue for the
year ended December 31, 1999 was $11.2 million. Mobeo accounted for 88.2% of
this subscriber revenue. Subscriber revenue for Mobeo increased from $7.1
million for the year ended December 31, 1997 to $8.6 million for the year ended
December 31, 1998 and to $9.9 million for the year ended December 31, 1999. The
increases from 1997 to 1998 and from 1998 to 1999 were primarily due to price
increases for Mobeo's foreign exchange information services.

     Engineering services revenue. Engineering services revenue decreased from
$1.6 million for the year ended December 31, 1997 to $1.0 million for the year
ended December 31, 1998 and increased to $2.6 million for the year ended
December 31, 1999. The decrease in engineering services revenue from 1997 to
1998 was primarily due to our decision to focus our efforts on developing our
AIM software platform and wireless data services. One of our investors accounted
for approximately 37% of engineering services revenue for 1997. The increase
from 1998 to 1999 was primarily due to the contract with OmniSky described in
the section entitled, "-- Overview." We recognized $2.2 million under this
contract for the year ended December 31, 1999.

     The acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed did not have a material effect on engineering services revenue on a pro
forma basis for the year ended December 31, 1999.

     Software and related services revenue. We did not earn any software and
related services revenue in 1997, 1998 and 1999. On a pro forma basis, giving
effect to the acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed, software and related services revenue was $2.3 million in 1999,
primarily as a result of licenses sold by Riverbed on its ScoutWare software
platform and systems integration and support services provided by LocusOne.

     Cost of subscriber revenue. Cost of subscriber revenue increased from
$447,480 for the year ended December 31, 1997 to $797,165 for the year ended
December 31, 1998 and to $2.1 million for the year ended December 31, 1999. We
began to incur costs of subscriber revenue in 1997 with the March 1997 launch of
our AirBroker service. The increase in the cost of subscriber revenue from 1997
to 1998 was primarily due to the launch of the Reuters MarketClip service in
March 1998. The increase from 1998 to 1999 was a result of an increase in
MarketClip subscribers, the introduction of TradeRunner and the acquisition of
Mobeo in September 1999. Cost of subscriber revenue from services acquired from
Mobeo
                                       31
<PAGE>   183

totaled $859,223 in 1999. We expect the number of subscribers for financial
services and online trading services to increase resulting in an increase in the
cost of subscriber revenue. Mobeo has entered into a new airtime supply
agreement with a paging company. In the first quarter of 2000, Mobeo will
provide a new pager to each of its subscribers at no cost as the existing pagers
are not compatible with the new supplier's network. As a result, we expect to
record approximately $500,000 of expense in the first quarter of 2000 relating
to supplying these pagers.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, cost of subscriber revenue for
the year ended December 31, 1999 was $4.6 million. Mobeo accounted for 73.0% of
these costs. Cost of subscriber revenue for Mobeo decreased from $3.1 million
for the year ended December 31, 1997 to $3.0 million for the year ended December
31, 1998 and increased to $3.4 million for the year ended December 31, 1999. The
decrease from 1997 to 1998 was primarily due to cost savings related to a change
in financial data providers and the increase from 1998 to 1999 was primarily due
to an increase in subscriber revenue. As a percentage of subscriber revenue,
cost of subscriber revenue decreased from 35.4% in 1998 to 34.3% in 1999.

     Cost of engineering services revenue. Cost of engineering services revenue
decreased from $846,140 for the year ended December 31, 1997 to $304,137 for the
year ended December 31, 1998 and increased to $1.4 million for the year ended
December 31, 1999. The decrease from 1997 to 1998 was primarily due to our
decision to focus our efforts on developing our AIM software platform and
wireless data services. The increase from 1998 to 1999 was primarily due to the
contract with OmniSky described in the section entitled, "-- Overview."

     The acquisitions of Mobeo and LocusOne and the pending acquisition of
Riverbed did not have a material effect on cost of engineering services revenue
on a pro forma basis for the year ended December 31, 1999.

     Cost of software and related services revenue. We had no costs associated
with software and related services revenue in 1997, 1998 and 1999. However, we
did incur research and development expenses as discussed below. On a pro forma
basis, giving effect to the acquisitions of Mobeo and LocusOne and the pending
acquisition of Riverbed, cost of software and related services revenue was $1.5
million in 1999 and included royalty fees and personnel costs of Riverbed and
LocusOne.

     Research and development expenses. Research and development expenses
increased from $733,630 for the year ended December 31, 1997 to $1.3 million for
the year ended December 31, 1998 and to $2.6 million for the year ended December
31, 1999. These increases in research and development expenses were primarily
due to the hiring of additional engineers for increased research and development
activities associated with the development of our AIM software platform and
wireless data services.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, research and development
expenses for the year ended December 31, 1999 were $5.5 million. Riverbed
accounted for 37.4% of the expenses, Mobeo accounted for 22.1% of the expenses
and LocusOne accounted for 1.0% of the expenses. Research and development
expenses for Mobeo increased from $174,867 for the year ended December 31, 1997
to $496,570 for the year ended December 31, 1998 and to $1.2 million for the
year ended December 31, 1999. The increase from 1997 to 1998 was primarily due
to an increase in the number of engineering personnel, and the increase from
1998 to 1999 was primarily due to additional expenses associated with the
development of wireless software applications.

     General and administrative expenses. General and administrative expenses
increased from $1.5 million for the year ended December 31, 1997 to $2.8 million
for the year ended December 31, 1998 and to $5.9 million for the year ended
December 31, 1999. These increases were primarily due to the addition of
personnel performing general corporate and business development functions.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, general and administrative
expenses for the year ended December 31, 1999 were $8.9 million. Mobeo accounted
for 16.6% of these expenses, Riverbed accounted for 11.8% of these
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<PAGE>   184

expenses and LocusOne accounted for 9.3% of these expenses. General and
administrative expenses for Mobeo increased from $1.9 million for the year ended
December 31, 1997 to $2.7 million for the year ended December 31, 1998 and to
$2.3 million for the year ended December 31, 1999 before pro forma adjustment.
The increase from 1997 to 1998 was primarily due to personnel and related costs.
The decrease from 1998 to 1999 is primarily attributable to decreased
compensation and professional fee expense as a result of our acquisition of
Mobeo.

     Selling and marketing expenses. Selling and marketing expenses increased
from $333,191 for the year ended December 31, 1997 to $840,455 for the year
ended December 31, 1998 and to $2.1 million for the year ended December 31,
1999. Of the increase from 1997 to 1998, $324,152 was due to an increase in
advertising and promotion costs related to the launch of Reuters MarketClip in
March 1998, and the remaining amount relates to an increase in personnel and
costs associated with sales and marketing. From 1998 to 1999, the increase
relates primarily to increases in the number of sales and marketing personnel.
This expense is expected to increase significantly in 2000 as a result of
increased spending in advertising.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, selling and marketing expenses
for the year ended December 31, 1999 were $6.8 million. Mobeo accounted for
26.6% of these expenses, Riverbed accounted for 41.9% of these expenses and
LocusOne accounted for 7.9% of these expenses. Selling and marketing expenses
for Mobeo increased from $1.8 million for the year ended December 31, 1997 to
$2.3 million for the year ended December 31, 1998 and to $2.6 million for the
year ended December 31, 1999 before pro forma adjustment. The increases from
1997 to 1998 and from 1998 to 1999 were primarily due to increased personnel
overhead costs.

     Depreciation and amortization expenses. Depreciation and amortization
expenses increased from $189,160 for the year ended December 31, 1997 to
$264,685 for the year ended December 31, 1998 and to $1.1 million for the year
ended December 31, 1999. The increase from 1998 to 1999 was primarily due to
amortization of goodwill and other intangibles related to the Mobeo acquisition
and additional capital expenditures.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, depreciation and amortization
expenses for the year ended December 31, 1999 were $386.4 million. This amount
primarily reflects amortization related to goodwill and other intangibles to be
recognized as a result of the acquisitions of Mobeo and LocusOne and the pending
acquisition of Riverbed.

     Option and warrant expense. Option and warrant expense decreased from
$40,277 for the year ended December 31, 1997 to $32,580 for the year ended
December 31, 1998 and increased to $19.2 million for the year ended December 31,
1999. The changes in option and warrant expense for 1998 and 1999 reflect
changes in the extent to which options with exercise prices less than the fair
value on the date of grant were granted during the period. Approximately $16.5
million of the expense in 1999 relates to warrants granted to the chief
executive officer and other key executives which became fully vested as a result
of our initial public offering.

     On a pro forma basis, giving effect to the acquisitions of Mobeo and
LocusOne and the pending acquisition of Riverbed, option and warrant expense for
the year ended December 31, 1999 was $33.5 million. The increase from Aether's
historical amount is primarily due to expenses associated with options granted
to employees of LocusOne and to the selling stockholders of Mobeo for consulting
and employee services.

     Interest income, net. Net interest income increased from $7,788 for the
year ended December 31, 1997 to $70,308 for the year ended December 31, 1998 and
decreased to net interest expense of $60,282 for the year ended December 31,
1999. The increase from 1997 to 1998 was primarily due to increased cash
balances as a result of our private placement financings completed in August
1998 and October 1998. The decrease to a net expense from 1998 to 1999 relates
to interest and related expense of a loan that

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<PAGE>   185

funded the purchase price of Mobeo, partially offset by interest earned on the
proceeds from our initial public offering. The loan was repaid at the time of
our initial public offering.

     Equity in losses of investments. Our equity in the loss of Real World
Solutions, a joint venture, and Navox, Inc., was $144,825 for the year ended
December 31, 1997. This amount related to losses of Real World Solutions and
Navox recorded by us under the equity method of accounting. The $2.4 million of
equity in losses of investments in 1999 relates to our proportionate share of
losses in OmniSky under the equity method of accounting.

     Realized loss on sale of investment. In the year ended December 31, 1997,
we sold our interest in Real World Solutions and recorded a loss of $302,145. In
the year ended December 31, 1999, we recorded a loss of approximately $169,000
resulting from the sale of short-term investments.

LIQUIDITY AND CAPITAL RESOURCES

     Since our inception, we financed our operations primarily through private
placements of our equity securities and our initial public offering, which in
the aggregate resulted in net proceeds of $116.8 million through December 31,
1999. As of December 31, 1999, we had $80.7 million in cash and short-term
investments and $83.1 million of working capital.

     Net cash used in operating activities was $1.5 million for the year ended
December 31, 1997, $4.4 million for the year ended December 31, 1998 and $12.1
million for the year ended December 31, 1999. The principal use of cash in each
of these periods was to fund our losses from operations. In October 1999, the
Company agreed to pay for the purchase of 25,000 Minstrel V modems from OmniSky
for a price per modem of $230. OmniSky has an exclusive buying arrangement with
Novatel for Minstrel V modems, which began in December and runs through March
2000. As of December 31, 1999 we have paid for 20,000 of the 25,000 modems for a
total purchase price of $4.6 million. The modems are being delivered to us
through April 2000.

     Net cash used in investing activities was $209,723, for the year ended
December 31, 1997, $6.5 million for the year ended December 31, 1998 and $12.6
million for the year ended December 31, 1999. Cash used in investing activities
for the year ended December 31, 1997 was primarily for the purchase of property
and equipment offset in part by proceeds from the sale of our joint venture
interest in Real World Solutions. Cash used in investing activities for the year
ended December 31, 1998 was primarily for the purchase of short-term
investments. For the year ended December 31, 1999, we invested $3.9 million in
short-term investments, $11.5 million to acquire Mobeo, $2.5 million to increase
our investment in OmniSky to 33% and $2.4 million in property and equipment.

     Net cash provided by financing activities was $1.8 million for the year
ended December 31, 1997, $12.5 million for the year ended December 31, 1998 and
$101.4 million for the year ended December 31, 1999. Cash provided by financing
activities in 1997 and 1998 was primarily attributable to proceeds from private
sales of our equity securities and cash provided by financing activities in 1999
consisting primarily of proceeds from our initial public offering. On September
28, 1999, we borrowed $14.8 million under a senior secured interim credit
facility with Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith
Incorporated, one of the underwriters of our initial public offering, and
Merrill Lynch Capital Corporation for the primary purpose of funding the
acquisition of Mobeo. On October 26, 1999, we completed our initial public
offering and raised net proceeds (after expenses of the offering) of
approximately $101.1 million. A portion of the proceeds of the initial public
offering was used to pay off the $14.8 million loan.

     On January 18, 2000, OmniSky sold equity capital through a private
placement and as a result we invested $6.7 million to retain our 33% interest in
OmniSky.

     On February 3, 2000, we acquired the capital stock of LocusOne for a
purchase price of $40 million, including $21 million in cash at the time of
closing. The remaining $19 million is in the form of two notes payable as
discussed below.

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<PAGE>   186

     For 2000, we expect to have the following additional expenditures and
requirements:

     - On February 7, 2000, we agreed to acquire a 27.5% interest in Inciscent
       for $10 million, a new company we formed with Metrocall, PSINet, Hicks,
       Muse, Tate & Furst and other investors through which we plan to develop
       wireless e-mail, Internet access and other applications for the small
       office and home office market segments. As part of the investment, we
       also agreed to acquire approximately 9.9% of the outstanding capital
       stock of Metrocall for approximately $17 million.

     - On February 8, 2000, we signed a letter of intent with Reuters to
       establish a European wireless company headquartered in the United
       Kingdom, which will be initially focused on financial markets. The letter
       of intent provides that we will acquire a 60% interest in the company for
       $100 million. The formation of this company remains subject to definitive
       documentation and our receiving money to fund the investment.

     - As part of our LocusOne acquisition, we issued two notes that are due in
       2000. One note totaling $5.4 million is payable at the time of the
       closing of this offering. The remaining $13.6 million note is payable at
       December 31, 2000 and will be repaid with proceeds of this offering to be
       placed in escrow.

     - We estimate we will pay $25 million to enhance our sales and marketing
       activities, $12 million of which we have already committed to spend for a
       nationwide broadcast and print branding and advertising campaign.

     - Other potential acquisitions, investments and agreements we may identify.

     We currently anticipate that our available cash resources combined with the
net proceeds from this offering and the concurrent offering of common stock will
be sufficient to fund our operating needs for at least the next 12 months,
including the expansion of our sales and marketing program. We expect that our
available cash resources combined with the net proceeds from these offerings
will also support our current acquisition strategy during this period.

YEAR 2000 IMPACT

     Many currently-installed computer systems and software products are coded
to accept or recognize only two digits rather than four digits to define the
year in the date code field. These systems and software products need to accept
four digit year entries to distinguish 21st century dates from 20th century
dates. Systems and products that are not corrected to do this could cause a
disruption of operations including a temporary inability to process
transactions, send invoices or engage in other normal business activities. We
maintain a significant number of computer software systems and operating systems
across our entire organization, which are potentially subject to year 2000
problems. Although January 1, 2000 has passed without any disruption of
operations, problems related to the year 2000 could still surface.

     The discussion below includes the products and infrastructure of Aether and
its recent acquisition, Mobeo, except where noted.

     We took several steps to prepare for the year 2000 transition. We developed
all our in-house software, including our AIM software platform, using four digit
date codes. We run all these applications on hardware and operating systems that
we have determined are year 2000 compliant. The Reuters MarketClip and Morgan
Stanley Dean Witter Online TradeRunner applications have operated successfully
in the year 2000. All our computer hardware has been inventoried and checked
against the manufacturers' year 2000 compliance declarations. All non-compliant
hardware was upgraded, or replaced. All third-party software, including
operating systems and applications, has been inventoried and checked against the
manufacturers' compliance statements. We upgraded and fixed software as
recommended by the manufacturers.

     We received assurances from external entities that could affect our
business. We have on file the compliance statements of our data providers,
landline and wireless network carriers, device manufacturers and current
corporate customers whose systems might impact our own systems.
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<PAGE>   187

     We have reviewed potential failures that may yet arise as a result of the
year 2000 transition. With the assistance of an outside consultant, we conducted
a business impact analysis and mapped the most critical of these failures into a
contingency plan that identified proactive measures to be taken to prepare for
system failures as well as those people responsible. In the event of a material
system or product failure in spite of our efforts to date, a crisis management
plan has been developed and is in place if needed.

     The most likely worst case scenario would be the failure of the landline or
wireless networks that carry data to us or from us to our customers. If this
happened, we would not be able to deliver our services to our customers and we
may lose revenue.

     Although we have taken the steps described above to make our systems year
2000 compliant and have experienced no year 2000 disruptions to date, we may
experience material problems and expenses associated with year 2000 compliance
that could adversely affect our business, results of operations and financial
condition. If the assurances we or our acquired companies have received from
third parties regarding their compliance is inaccurate we may experience
disruption resulting in additional expense and loss of revenue. We are also
subject to outside forces that might generally affect industry and commerce,
such as year 2000 compliance failures by utility or transportation companies. If
our customers experience disruptions related to our services and software
systems, they may begin litigation against us even if the disruptions were
caused by their own systems or software provided by others.

     We have purchased most of our equipment within the last four years, which
has kept the costs of year 2000 compliance efforts to a minimum. All
non-compliant software and equipment has been upgraded or replaced at a cost
that is not material to us and our total costs relating to year 2000 compliance
have been less than $100,000. Based on our review of compliance to date, we do
not expect any future costs related to year 2000 compliance to be material.

     Riverbed was established in October 1998 and thus substantially all of its
network systems, personal computers, laptop computers and handheld computers
were purchased during 1999. Equipment and applications were purchased only from
vendors with favorable year 2000 compliance statements. Riverbed software
applications were tested for year 2000 compliance and defects were repaired. No
disruption of operations occurred during the transition to January 1, 2000.

     LocusOne validated its hardware and software systems against vendor
compliance statements. One server was determined to be non-compliant and was
replaced. The software of one of LocusOne's wireless network carriers had
several year 2000 formatting problems that LocusOne accommodated in its software
and procedures. These formatting problems do not affect the operation of the
wireless service. LocusOne tested its software and systems for year 2000
compliance and all systems and services functioned properly. No disruption of
operations occurred during the transition to January 1, 2000.

NEW ACCOUNTING PRONOUNCEMENTS

     In June 1998, the FASB issued SFAS No. 133, "Accounting for Derivative
Instruments and Hedging Activities." The new standard establishes accounting and
reporting standards for derivative instruments, including certain derivative
instruments embedded in other contracts and for hedging activities. This
statement, as amended, is effective for all fiscal quarters beginning after June
15, 2000. We do not expect SFAS No. 133 to have a material effect on its
financial position or results of operations.

QUALITATIVE AND QUANTITATIVE DISCLOSURE REGARDING MARKET RISK

     We have limited exposure to financial market risks, including changes in
interest rates. We manage our interest rate risk exposure by investing in debt
obligations with varying maturity dates. At December 31, 1999, we had short-term
investments of approximately $2.1 million. These short-term investments
consisted of highly liquid investments in debt obligations of the U.S.
Government and other highly-rated entities with maturities of up to 30 years.
These investments are classified as available-for-sale and are considered
short-term, because we expect to sell them within 12 months. These investments
are subject to interest rate risk and will fall in value if market interest
rates increase. At December 31, 1999,

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<PAGE>   188

the value of our short-term investments was approximately $70,069 less than our
cost. If market interest rates continue to rise, the value of our short-term
investments will continue to decrease. We expect to sell these investments prior
to maturity, and therefore we may not realize the full value of these
investments. We currently hold no derivative instruments and do not earn
foreign-source income. We expect to invest only in short-term, investment grade,
interest-bearing instruments.

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<PAGE>   189

                                    BUSINESS

OVERVIEW

     We provide wireless data services, systems and software enabling people to
use handheld devices for mobile data communications and real-time transactions.
We design, develop, sell and support complete wireless systems for corporations
seeking to make data available to mobile workers or consumers. Our capabilities
include our wireless data engineering and development expertise, our wireless
integration software, our customer service and network operations center and,
following our acquisition of Riverbed, our mobile data management software.

MARKET OPPORTUNITY

  Growth of the Internet, Intranets and Extranets

     The Internet and businesses' internal data networks, or intranets, have
emerged as global communications channels that allow users to share information
and conduct real-time business electronically. Technology and communications
research firm International Data Corporation, or IDC, estimates there were
approximately 212 million worldwide users of the Internet at the end of 1999 and
that the number of users will increase to 510 million by the end of 2003. IDC
also estimates that by 2001 there will be 133 million global intranet users.
Businesses are also increasingly employing extranets, which allow them to
communicate and conduct transactions electronically with their customers and
suppliers. Forrester Research forecasts that business-to-business Internet
commerce in the United States will increase from an estimated $406 billion in
2000 to $2.7 trillion in 2004. All of the projections and estimates in this
"Market Opportunity" section are based on the qualifications described on page
21 of this prospectus.

  Growth of Mobile Communications

     Individuals are increasingly using mobile devices for convenience and
enhanced productivity when away from their home or office. IDC estimates that in
1998 there were 303 million worldwide cellular and personal communications
systems, or PCS, subscribers, and that number is expected to increase to 1.1
billion in 2003. Use of wireless telecommunications has grown rapidly as
cellular, paging and PCS have become more widely available and affordable for
both the business and mass consumer markets. Advances in technology, regulatory
changes, the introduction of new service providers and price reductions have
contributed to this growth.

  Growth of Wireless Data Applications and Communications

     We believe an increasing number of people will carry wireless devices for
data communications rather than for voice communications alone. The latest
wireless communications devices in the United States, including handheld
personal organizers, notebook computers, pagers and mobile phones, are smaller,
less expensive, have longer battery life and more features than earlier devices.
According to publicly available estimates, the U.S. wireless data market will
grow from 3 million subscribers in 1999 to 36 million subscribers in 2003.
Forrester Research forecasts that 7.1 million European business professionals
and young adults will own Web-enabled smartphones using the Wireless Application
Protocol, or WAP, by the end of 2000 and that there will be 40 million Europeans
using WAP smartphones by the end of 2001.

     The market for wireless data applications is driven by the increased
reliance on the Internet, intranets and extranets and the emergence of a mobile
workforce. IDC forecasts that the remote and mobile workforce in the United
States will grow from 35.7 million individuals at the end of 1999 to 47.1
million at the end of 2003. Having grown accustomed to and dependent on the
information and applications available on their personal computers, we believe
workers and consumers want access to similar information when away from their
office or home.

  Increased Outsourcing Trends

     As information technology, or IT, systems have become more complex,
companies have increasingly outsourced many of their IT requirements. U.S. firms
are now spending 20% of their IT budgets on

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<PAGE>   190

outsourcing services, according to the industry trade publication Internet Week.
These include packaged application software implementation and support, customer
support and network development and maintenance. Companies are choosing to focus
on their core businesses and seeking to reduce costs associated with developing
and maintaining IT networks and software applications. In addition, by
outsourcing, companies avoid major challenges faced in hiring and retaining
qualified IT employees and realize increased time-to-market benefits.

THE AETHER SOLUTION

     Mobile workers and consumers typically gain remote access to electronic
data and transactional capabilities in one of two ways:

     - through continuous, real-time communications between databases and
       handheld devices using wireless communications networks, or

     - by periodically updating, or synchronizing, data between the device and
       database using a direct connection, such as a phone line.

We provide the services and resources necessary to provide these capabilities
using our engineering staff, our wireless integration and mobile data management
software and our customer service and network operations center. Our
capabilities address most of the common issues companies face when building and
supporting wireless and other mobile data systems.

     Issue:  Wireless and other mobile data communications systems are complex.

        Many information technology managers lack the engineering and system
        resources to design, develop, install and maintain new software and
        systems that give their companies' workforces and customers mobile
        access to corporate applications.

     Solution:  We provide comprehensive mobile communications services.

        We have all the resources necessary to design, develop, install and
        maintain wireless and other mobile data communications systems for
        customers. We have 50 engineers, and with the pending acquisition of
        Riverbed we will add 34 engineers. Our engineers use our Aether
        Intelligent Messaging software platform, or AIM, to extend corporate
        applications to almost any wireless environment. Through our pending
        acquisition of Riverbed, we also will provide a complete suite of
        software products that extend corporate data to mobile handheld devices.
        We have established relationships with the leading wireless network
        carriers, including AT&T Wireless Services, Bell Atlantic Mobile,
        BellSouth Wireless Data and GTE Corp. We have negotiated favorable
        airtime agreements with these carriers, allowing us to offer our end
        users flat-rate pricing no matter how much data is transmitted or where
        a device is used. Our network operations center offers a secure gateway
        to wireless networks for data delivered to us by our customers, and our
        customer service center provides devices and call center support to end
        users. We provide as many, or as few, of these elements as customers
        require to develop their systems.

     Issue:  There is a wide variety of incompatible standards.

        To build a wireless data system, a business must integrate disparate
        networks, devices and operating systems. Companies often require
        multiple networks to meet the needs of their workers and customers,
        based on their geographic location and preferred devices, which may use
        different communications protocols. This can involve complex
        negotiations with several wireless carriers. Additionally, companies
        typically use a variety of operating systems for their internal data
        applications.

     Solution:  Our software and systems can integrate a wide variety of
                networks, devices and operating systems.

        We give our customers a high degree of flexibility and choice, freeing
        them from the need to integrate technologies from a variety of parties
        to develop their systems. Our AIM software platform supports the most
        widely used wireless data networks in the United States, known as CDPD,
        Mobitex and ARDIS, as well as circuit-switched network protocols,
        including GSM and CDMA. As a result, our customers' end users can choose
        the devices they prefer, including Palm, Windows CE

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<PAGE>   191

        and other personal organizers, notebook computers, pagers and mobile
        phones. Our WAP Enterprise Center has a team of engineers and sales
        executives dedicated to supporting and developing applications for WAP,
        a series of specifications that allow mobile phones to display Internet
        information. We also are planning to extend our AIM software platform's
        capabilities to the Microsoft micro-browser and the operating system
        known as EPOC for handheld devices developed by Symbian Ltd. (a wireless
        software company jointly owned by Ericsson, Matsushita Communication
        Industrial Co., Ltd., Motorola, Nokia and Psion PLC). Our AIM software
        platform can interact with the major operating systems on which most
        corporate applications run, including Windows NT, UNIX, Linux and most
        mainframe operating systems.

        As connections to new systems have become needed, our engineers have
        adapted our AIM software platform to meet the needs of those systems. We
        believe that as the wireless data market evolves there will continue to
        be a multitude of protocols for networks, devices and operating systems.
        We plan to update our software platforms continually to address the
        ongoing need to integrate these protocols. We believe we are the only
        firm that currently provides this level of service to companies seeking
        to develop wireless data systems.

     Issue:  Wireless data transmissions are slow and expensive.

        Most of today's wireless data networks operate at less than half the
        speed of telephone dial-up connections, limiting the delivery of useful
        data to only small amounts of text and few graphics. Data feeds
        typically include large amounts of unnecessary data, including message
        headers and routing information. Because wireless carriers typically
        charge by the kilobyte of data transmitted, extraneous data add
        unnecessary cost.

     Solution:  Our systems optimize data transmissions for wireless networks.

        Our AIM software platform optimizes data transmission by employing
        compression and data-thinning techniques. As a result, users get
        information faster when they send queries from their devices, and they
        get more useful information for the price. Our AIM software platform
        reduces the number of data packets required in a typical wireless
        transmission by as much as 66%. We ensure reliable message delivery
        through measures that confirm data have arrived properly and resend data
        if no acknowledgement has been received.

        Over the next several years, wireless carriers and equipment vendors are
        planning to build so-called third generation, or 3G, networks, which
        promise to transmit data at much higher speeds and offer more
        compatibility among devices. No matter how fast networks become, the
        need for low cost, secure and reliable data transmission will continue.
        We have designed our AIM software platform to grow with the capabilities
        of wireless networks. For example, we are currently working with U.S.
        and European wireless network carriers to develop our financial trading
        services to operate over networks using General Packet Radio Services,
        known as GPRS, a new high-speed wireless network standard.

     Issue:  Corporate managers require rigorous security standards when
             entrusting their data to third parties.

     Solution:  We provide a secure network operations center.

        Our network operations center has numerous redundant elements and serves
        as a high-security physical link between data feeds from our business
        customers' and others' data systems and wireless carrier networks. This
        relieves corporations from the burden of constructing similar
        facilities. We believe our network operations center is capable of
        meeting the security standards for services we developed or are
        developing for our customers, who include Reuters, Morgan Stanley Dean
        Witter Online and Charles Schwab. We believe that our network operations
        center is a vital component of our wireless data service offerings that
        differentiates us from our competitors. We encrypt, or scramble, digital
        messages as they move along wireless networks using technology licensed
        from Certicom Corp. Recently we reached an agreement to use "digital
        signature" technology provided by Diversinet, which authenticates the
        identity of the sender and recipient of such messages.

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<PAGE>   192

     Issue:  Corporate information technology managers are reluctant to
             configure and maintain inventories of wireless devices and provide
             ongoing customer support.

     Solution:  We provide product fulfillment and customer service.

        We send end users fully functioning mobile devices configured for the
        wireless data networks and applications they will use. We also have a
        customer service center providing ongoing end user support. Companies do
        not have to worry about configuring devices for use by their employees
        and customers, fixing broken units, handling warranties or answering
        questions from users.

THE AETHER STRATEGY

     Our strategy is to be the dominant provider of wireless data services and
systems to corporations by using our engineering expertise, our software
platforms, our customer service and network operations center and our other
resources. We seek to maximize recurring revenue by developing wireless data
services. We believe our capabilities and experience have established us as an
early market leader in wireless data services, and a key element of our strategy
is to move quickly into new opportunities to extend our leadership position. Our
strategy includes the following key elements:

     Target a variety of industries and market segments for development of
wireless data communications and services in the United States and
internationally. Our strategy initially focused on developing services for the
financial services sector, whose participants we believe are among the earliest
adopters of wireless data services. While seeking to extend our offerings in the
financial services sector, we also seek to move into other industries and market
segments in the United States and internationally. Since January 2000, we have
entered into the following acquisitions, investments, agreements and letters of
intent in pursuit of this strategy:

     - We agreed to acquire Riverbed, a company that develops and licenses
       mobile data management software. This pending acquisition gives us access
       to the industries Riverbed currently serves, including healthcare,
       transportation logistics and sales force automation.

     - We acquired LocusOne, which develops wireless data systems for companies
       that distribute goods and services using their own delivery fleets. This
       acquisition extends our business to the transportation logistics and
       delivery industry.

     - We entered into a non-binding letter of intent with Reuters to form a new
       company to develop wireless data systems in Europe, initially focusing on
       the financial services industry.

     - We agreed to form a new company, Inciscent, to develop wireless e-mail,
       Internet access and other applications for the small business and home
       office market segments. We agreed to form Inciscent with paging company
       Metrocall, Internet service provider PSINet, investment firm Hicks, Muse,
       Tate & Furst and other investors.

     - We increased our investment in OmniSky, a company we formed with 3Com.
       With our engineering assistance, OmniSky is developing wireless e-mail,
       Internet access and other electronic transactions capabilities primarily
       for the consumer market, and we have the right to offer these
       capabilities to our business customers.

     - We entered into a non-binding memorandum of understanding with Nextel
       Finance Company to develop wireless data services using the Nextel
       wireless communications network. Nextel and Aether plan to jointly
       develop and market applications for mobile workforces in financial
       services, transportation and other industries. Applications are being
       planned for WAP-enabled Nextel phones as well as for Palm and Windows CE
       devices that are connected to Nextel wireless phones.

     - We entered into a non-binding letter of intent with Proxicom, Inc., an
       Internet consulting and development company, to jointly pursue
       opportunities to provide wireless data services to companies.

     - We entered into a non-binding letter of intent with CyberBills, an online
       bill-paying service, to develop a wireless electronic bill presentment
       and payment service for CyberBills' consumer distribution network.

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<PAGE>   193

     Continue to develop the market for existing and new services in the
financial services sector.  We believe that news, stock prices and other
financial information are among the most accessed content on the Internet. The
Internet has also enabled the growth of online trading activity. We have
targeted two types of financial services subscribers, individual investors and
market professionals, each of whom understands the value of receiving real-time
information and trading capabilities. We are currently focused on launching
commercial service for our most recent customers and attracting additional
financial institutions as customers.

     Offer the widest range of software products that address every aspect of
wireless integration and mobile data management for mobile workers and
consumers.  We plan to provide services and products that meet all mobile and
wireless software needs, including our AIM wireless integration software and the
ScoutWare mobile data management software suite, which we will offer following
our acquisition of Riverbed. These offerings give corporate software engineers a
complete set of development tools for designing mobile and wireless data
applications for a wide variety of handheld devices and networks.

     Continue to develop mass-market wireless applications like e-mail and
Internet access and bundle them with custom corporate applications.  Our
involvement with OmniSky, a company we formed in August 1999 with 3Com, allows
us to combine, or "bundle," our custom corporate wireless data services with
wireless e-mail and Internet access offered by OmniSky. We also recently
announced the formation of our WAP Enterprise Center, which provides engineers
who develop applications for wireless phones that offer data services (so called
WAP smartphones) and the systems to support data communications to these
devices. Through our recent investment in Inciscent, a company we formed with
Metrocall, PSINet, Hicks, Muse, Tate & Furst and other investors, we also plan
to develop wireless e-mail, Internet access and other applications for the small
office and home office market segments.

     Expand our customer base and strengthen the Aether brand through enhanced
sales and marketing efforts.  We are increasing our sales and marketing
expenditures significantly to increase our direct sales force and advertise the
Aether brand. We intend to build our sales force focused on companies that want
to provide wireless access to their data applications. Following our acquisition
of Riverbed, we will incorporate its ScoutWare software sales force with our AIM
software platform sales effort. We will target large corporations in industries
that both invest heavily in technology and have significant numbers of mobile
customers or employees. In addition, we will continue to build relationships
with third party software developers who wish to use our software platforms to
provide their applications with wireless capabilities. Our branding efforts will
include advertising, public relations, speaking engagements and sponsorship of
major conferences.

     Maintain and strengthen our strategic relationships with suppliers and
customers.  A key to our ability to provide complete wireless data services to
our customers is our relationships with wireless network carriers and
manufacturers of wireless devices. These relationships take time to develop,
providing us with an advantage by getting our services to market before our
competitors. We intend to maintain and strengthen these relationships by
negotiating more cost-effective rate plans with existing wireless network
carriers, testing our wireless services with providers of next-generation,
high-speed wireless networks and working with manufacturers and industry forums
to guide development of new devices and applications.

     Apply the expertise we gain through engineering services and research and
development activities to emerging business opportunities.  While we no longer
provide engineering services strictly to generate revenue, we do take on
engineering assignments that might allow us to embrace technological advances or
expand into new industry sectors or services. To this end, we have established a
new research and development division that will evaluate new technologies,
applications and business opportunities that demonstrate significant market
potential. The division will initially be staffed by seven engineers, including
our chief technology officer, who will head that division.

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<PAGE>   194

SERVICES AND PRODUCTS

     The services and products we currently offer or are developing or acquiring
include:

     - delivering wireless information and transaction services;

     - software licensing; and

     - providing engineering services for the design, development and support of
       wireless data systems.

     The following table sets forth summary information regarding services and
products we now offer or are developing or acquiring.

WIRELESS INFORMATION AND TRANSACTION SERVICES
- --------------------------------------------------------------------------------

<TABLE>
<CAPTION>
         SERVICE                USERS OF SERVICE      DATE INTRODUCED    REVENUE TYPE             SERVICE DESCRIPTION
- --------------------------  ------------------------  ---------------  -----------------  -----------------------------------
<S>                         <C>                       <C>              <C>                <C>
EXISTING FINANCIAL SERVICES
  Reuters MarketClip        Individual investors      March 1998       Monthly recurring  Market quotes, news and alerts
  TradeRunner               Morgan Stanley Dean       August 1999      Monthly recurring  Equities and options trading,
                            Witter Online investors                                       market quotes, news and alerts
  F/X Alert                 Financial market          September 1999   Monthly recurring  Foreign exchange quotes, news and
                            professionals                                                 alerts

FINANCIAL SERVICES UNDER DEVELOPMENT
  PocketBroker              Charles Schwab online                      Monthly recurring  Equities and options trading,
                            investors                                                     market quotes, news and alerts
  PitViper                  Chicago Board of Trade                     Monthly recurring  Entry and reconciliation of
                            floor traders                                                 commodities orders
  Name to be determined     National Discount                          Monthly recurring  Equities and options trading,
                            Brokers online investors                                      market quotes, news and alerts
  Name to be determined     Brokers or firms                           Monthly recurring  Customer account access and
                            clearing through Bear                                         trading, market quotes, news and
                            Stearns                                                       alerts
  Name to be determined     TD Waterhouse Investor                     Monthly recurring  Equities and options trading,
                            Services online                                               market quotes, news and alerts
                            investors

WIRELESS TRANSPORTATION & DELIVERY SERVICES
  e-Mobile Delivery         Physician Sales &         January 1998     Monthly recurring  LocusOne software suite and
                            Service                   September 1998   and/or licensing   application service that enables
                            MAC Papers                June 1999                           wireless transactions at the point
                            Office Depot              September 1998                      of sale, customer contact or
                            NuCo2                     August 1999                         delivery
                            Suntory Water Group
</TABLE>

<TABLE>
<CAPTION>
SOFTWARE LICENSING
- ----------------------------------------------------------------------------------------------------------------------------------
PRODUCT                     LICENSEES OF SOFTWARE     DATE OF CONTRACT  REVENUE TYPE       SOFTWARE FUNCTION
- --------------------------  ------------------------  ----------------  -----------------  ---------------------------------------
<S>                         <C>                       <C>               <C>                <C>
  Aether Intelligent        Inciscent*                                  Upfront and/or     Allows for secure, efficient transport
    Messaging                                                           per-user           of data over wireless networks; also
                                                                        licensing fees     provides tools for wireless
                                                                                           applications development
  ScoutWare**               Palm Computing            September 1999    Per-user           Riverbed ScoutWare software suite links
                            U.S. Postal Service       June 1999         licensing fees     mobile devices to corporate data
                            Becton Dickinson          November 1999                        systems, provides application
                            Oracle                    March 1999                           development and management tools
</TABLE>

 * We will license AIM to Inciscent for a one-time charge of $1 million when we
   close our investment in Inciscent. We currently license AIM to Riverbed, whom
   we are acquiring, and have licensed AIM to OmniSky on a royalty-free basis in
   connection with our equity investment in OmniSky.
** We will acquire ScoutWare upon our acquisition of Riverbed.

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<PAGE>   195

<TABLE>
<CAPTION>
ENGINEERING SERVICES
- -----------------------------------------------------------------------------------------------------------------------
CUSTOMER                    DATE OF CONTRACT          REVENUE TYPE     SERVICE DESCRIPTION
- --------------------------  ------------------------  ---------------  ------------------------------------------------
<S>                         <C>                       <C>              <C>
  Response Services Center  January 2000              Engineering      Develop location-tracking capabilities for
                                                      fees             towing firms, vehicle fleets
  Merrill Lynch             October 1999              Engineering      Develop wireless financial services for
                                                      fees             financial professionals
  OmniSky                   August 1999               Engineering      Develop and provide e-mail, Internet access and
                                                      fees             electronic transactions capabilities on wireless
                                                                       handheld devices
</TABLE>

  Wireless Information and Transaction Services

     Our wireless information and transaction services and customers are
described below.

     - Reuters MarketClip.  In March 1998, we introduced the Reuters MarketClip
       service, which delivers news stories, real-time financial market price
       quotes, historical graphs and stock alerts from Reuters to Palm and
       Windows CE devices. We charge individual subscribers a flat monthly fee
       for unlimited usage of this service in addition to the fees charged by
       the securities exchanges and markets for the right to view real-time
       price quotes. The service operates using the wireless network systems
       known as CDPD and Mobitex. These networks cover geographic areas that
       enable us to provide service to more than 90% of the U.S. population. We
       also continue to support AirBroker, a predecessor service to Reuters
       MarketClip that provides market information using mobile phones.

     - Morgan Stanley Dean Witter Online TradeRunner.  In August 1999, we
       launched TradeRunner, a service that allows Morgan Stanley Dean Witter
       Online's customers to trade stocks, mutual funds and options using Palm
       devices. In addition, subscribers receive news stories, real-time
       financial market price quotes, historical graphs and stock alerts from
       Reuters. We charge Morgan Stanley Dean Witter Online account holders who
       subscribe to this service a flat monthly fee for unlimited usage, in
       addition to the fees charged by the securities exchanges and markets for
       the right to view real-time price quotes. Users pay Morgan Stanley Dean
       Witter Online's regular commission fees for any trades. We support
       TradeRunner through our customer service and network operations center.
       The service operates using CDPD or Mobitex networks.

     - F/X Alert.  As a result of the Mobeo acquisition, we offer real-time
       information on foreign exchange rates and selected commodities markets.
       These services deliver time-sensitive financial information from Reuters
       over wireless networks that reach the largest 100 metropolitan markets in
       the United States. F/X Alert offers real-time price quotes, news and
       alert tracking for more than 150 financial instruments including foreign
       exchange, fixed income, futures/derivatives and commodities. In addition,
       we continue to offer other Mobeo services, called Scrappy, Energy and
       Pocket Futures, which track the scrap metals, energy and futures markets,
       respectively, as well as Mobeo 1.0, a two-way financial market price
       quotes and information service, similar to MarketClip, that operates
       using the RIM 950 two-way pager.

     - Charles Schwab PocketBroker.  In December 1999, we signed a definitive
       agreement with Charles Schwab to develop a wireless financial trading and
       information service for Schwab's brokerage customers. We are currently
       testing a pilot version of the service. We and our network carriers have
       agreed to pay for advertising and marketing of this service and match the
       amount spent by Schwab up to an agreed upon maximum amount. In addition,
       we have agreed to provide engineering support to implement Schwab's
       service at no charge for two years. At launch, we will charge Schwab
       customers who subscribe to this service a flat monthly fee for unlimited
       usage.

     - Chicago Board of Trade PitViper.  In June 1999, we began a limited trial
       of a wireless trade recording system, PitViper, for the Chicago Board of
       Trade. This trial allows up to 15 users of Palm devices to track and
       record trades executed on the floor. Once a trade is entered on PitViper,
       the terms of the trade are transmitted to Chicago Board of Trade's trade
       confirmation system.

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<PAGE>   196

       Traders can also access real-time price quotes for commodities and
       futures as well as news stories. We expect that the Chicago Board of
       Trade will make PitViper available to the approximately 3,500 Chicago
       Board of Trade floor traders if the trial succeeds. We intend to charge
       individual subscribers a flat monthly fee for the service.

     - Additional financial services under development.  We are also developing
       wireless financial trading and information services for National Discount
       Brokers, Bear Stearns and TD Waterhouse Investor Services. We announced
       our agreement to build a wireless financial trading and information
       service for National Discount Brokers in November. That agreement calls
       for us to develop wireless stock-trading capability along with OmniSky's
       wireless e-mail and Internet access on Palm, WindowCE and other devices.
       The Bear Stearns project involves developing wireless trading
       applications for its brokers, clients and other financial professionals.
       We recently signed a letter of intent to develop a wireless financial
       trading and information service for TD Waterhouse. The Bear Stearns and
       TD Waterhouse projects are each in a preliminary stage, and we cannot
       assure you that definitive agreements will be signed for either of them.

     - Wireless transportation and delivery services (e-Mobile
       Delivery).  e-Mobile Delivery, a service we offer following our
       acquisition of LocusOne, allows corporations to track customer orders,
       inventory and fleet vehicle locations more efficiently. The e-Mobile
       Delivery group of products offers comprehensive ways to automate the
       point of customer contact, sales, delivery or service. These products
       integrate with corporate data systems and work using a variety of wired
       and wireless communications networks. LocusOne customers for the e-Mobile
       group of products include Physician Sales & Service, MAC Papers, Office
       Depot, NuCo2 and Suntory Water Group.

  Software Licensing

     We currently license our AIM software platform, which is the core
technology underpinning most of our wireless data services, and will license the
ScoutWare software platform when we complete our acquisition of Riverbed. We
describe these software platforms below.

     Aether Intelligent Messaging

     AIM is a package of wireless messaging software and development tools -- or
software platform -- that facilitates the development of wireless data systems.
We developed the AIM software platform in 1997 to improve the performance of
data delivery over wireless networks and to provide a development kit to speed
the software development process. We use the AIM software platform internally to
develop and support the wireless data services we offer our customers. We have
launched a program to license the AIM software platform to both software
developers and large corporations. Software developers can integrate the AIM
software platform with their applications to provide those applications with a
wireless capability. When the AIM-based application is sold, we can then earn
one-time revenue from per-user license fees or recurring revenue if the
application is run from our network operations center. Similarly, corporate
customers who develop AIM-based applications for their own use can pay us
license fees per user or recurring services fees if we host the application.

     How the AIM Software Platform Works.  The diagram below illustrates how the
AIM software platform works to integrate sources of data with wireless networks
and devices. Data and applications come from internal corporate systems, such as
those at Morgan Stanley Dean Witter Online, from public data sources via the
Internet or from proprietary systems such as Reuters Selectfeed Plus. The AIM
software platform then takes the data, replaces unnecessary or repetitive
message-header information with more streamlined tags, compresses and encrypts
it so the data can move quickly and securely outside the security system (or
"firewall"), controlling access to and from the source's network, and then sends
it over the airwaves using any of a number of wireless networks to the intended
device. Not all devices will work on all wireless carrier networks. Our AIM
software platform can be configured to support other networks as they are
developed and as customer needs require.

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                           [HOW AIM WORKS FLOW CHART]

     The AIM software platform has the following features and benefits.

     - The AIM software platform enhances the speed, efficiency and security of
       data transmission over wireless networks.  The AIM software platform
       trims unnecessary electronic message tags and compresses data, with no
       loss in the reliability of message delivery. As a result, users get data
       quickly and at a low cost. The AIM software platform uses a sophisticated
       technology known as elliptic curve cryptography, or ECC, which was
       developed by Certicom, to encode the data so it cannot be read by a third
       party that intercepts the data. Additionally, we recently reached an
       agreement to use "digital signature" technology provided by Diversinet,
       which authenticates the identity of the sender and recipient of such
       messages.

     - The AIM software platform simplifies programming required to convert data
       into a form that can be transmitted over wireless networks.  The AIM
       software platform uses industry-standard programming languages and
       includes application program interfaces. The AIM software platform comes
       with a software development kit that provides programmers step-by-step
       guides and automatically generates code for major system components based
       on the options selected. As a result, programmers can focus on the
       business objectives the system is designed to meet, rather than becoming
       immersed in unfamiliar and complex software and wireless network
       protocols.

     - The AIM software platform facilitates the interaction of major operating
       systems on which most corporate applications run with the most widely
       used wireless data networks and devices.  To date, the AIM software
       platform is compatible with the following wireless network carrier
       protocols, mobile device operating systems and corporate operating
       systems:

        - wireless network carrier protocols: CDPD, Mobitex and ARDIS;

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        - mobile device operating systems: Palm computing platform, Windows CE,
          two-way pagers and Windows 95/98/NT and their corresponding modems;
          and

        - corporate operating systems: Windows NT, Sun Solaris and Linux.

     As a result, our business customers can offer a wide variety of
applications for wireless transmission, and end users can similarly choose from
a number of devices. Our engineers continually develop the capabilities of the
AIM software platform as new protocols, devices and systems emerge.

     ScoutWare

     Through our pending acquisition of Riverbed, we plan to offer Riverbed's
ScoutWare family of software products. ScoutWare is a package of mobile data
management software and development tools that allows remote and mobile workers
to exchange information with corporate databases and the Internet. ScoutWare
also gives information technology personnel tools to manage, deploy and connect
their corporate data with handheld devices. We plan to integrate ScoutWare with
our AIM wireless integration platform, to offer customers a complete set of
wireless and mobile data solutions. ScoutWare products reside both on handheld
devices and on corporate computer servers. Mobile workers use ScoutWare when
they electronically exchange, or synchronize, data between their handheld
devices and corporate databases. There are four product categories in the
ScoutWare software suite -- ScoutSync, ScoutIT, ScoutArchitect and
ScoutWeb -- each of which is explained below:

     - ScoutSync provides the core connection between a handheld device and a
       corporate database. ScoutSync operates on both the Palm Operating System
       and the Windows CE operating system to connect to a corporate network
       using the common Internet protocol TCP/IP. Any number of remote devices
       may be simultaneously connected to a single network, and the devices can
       be a combination of Palm or Windows CE devices. ScoutSync can exchange
       information either over a wireless network or through a cradle that is
       connected to a computer linked to a corporate network. ScoutSync is made
       up of four key components, illustrated in the diagram below:

                                    [CHART]

        (1)  ScoutSync Client, a software application that is loaded
             into the handheld device, allows the device to initiate and
             carry out a synchronization session.
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        (2)  ScoutSync Server, a software application that resides on a
             computer workstation linked to the corporate network,
             allows two-way communication between a device and corporate
             data sources and lets system administrators monitor, update
             and back up remote devices.

        (3)  ScoutSync Service, a set of computerized instructions that
             resides on the ScoutSync Server, manages central processing
             components, called "conduits," enabling them to transfer
             data between the remote device and a corporation's software
             programs.

        (4)  ScoutSync Conduit, a central processing component that
             resides on a ScoutSync Server, carries out synchronization
             tasks and can access and manipulate files and databases on
             both the corporate database side and the mobile device
             side.

     - ScoutIT allows corporate information technology professionals to manage
       the interaction between corporate databases and handheld
       devices.  Residing on a Windows NT server, ScoutIT allows information
       technology managers to control how handheld devices share information
       with corporate databases. Managers can administer a system allowing
       thousands of remote devices to send and receive information from a single
       location, including backing up and restoring data to ensure security,
       upgrading and configuring applications and tracking how applications are
       being used.

     - ScoutArchitect is a package of software applications and software
       developer tools that allows developers to create mobile-ready versions of
       their corporate software applications.  ScoutArchitect allows corporate
       developers to quickly identify the most critical elements of a corporate
       software application for a handheld device. Applications can be developed
       independent of the software the device operates on or development
       environment, allowing the customer to avoid reconstruction of critical
       elements of an application when moving to different operating software or
       development tools. ScoutArchitect also includes programmer and
       application interfaces that allow independent software vendors to write
       handheld device applications that can plug into their own applications
       and systems.

     - ScoutWeb will allow handheld devices to receive Internet and intranet
       data.  Riverbed is developing ScoutWeb to manipulate data from the
       Internet so that the data can be effectively used on mobile devices,
       including WAP smartphones. We expect ScoutWeb will be available for
       commercial use by March 2000.

  Engineering Services

     We began operations in 1996 by providing engineering services to businesses
seeking to develop wireless data systems. Our customers have included the U.S.
Postal Service and Reuters Group Overseas Holding(UK) Limited. Our engineers
have experience in developing wireless applications for a variety of businesses.

     Since 1998, we have focused our efforts more on developing wireless data
services that will result in recurring subscription revenue to us. While we
therefore no longer provide engineering services strictly to generate revenue,
we do take on engineering assignments that might allow us to embrace
technological advances or expand into new industry sectors or services. In
addition to our contract with OmniSky, our current engineering services clients
include Response Services Center, LLC, an emergency vehicle response company,
and Merrill Lynch, Pierce, Fenner & Smith Incorporated. Through our work with
Response Services, we hope to develop new services for the transportation
industry. Through our work with Merrill Lynch, we are developing wireless
financial information services for financial professionals. We generally charge
our clients for engineering time on an hourly basis or a per project flat fee.

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OMNISKY

     We believe we can provide our corporate customers with more attractive
service offerings by coupling general wireless applications like e-mail and
Internet access with custom corporate applications. Our involvement with
OmniSky, a company we formed in August 1999 with 3Com, allows us to achieve
this. OmniSky's main business objectives and strategies include those set forth
below.

     - OmniSky will pursue opportunities in the emerging consumer and business
       mass markets by developing a package of applications and services that
       includes a selection of Web sites that have been customized for access
       via wireless handheld devices, general Web browsing, access to a user's
       existing e-mail account and selected Internet and electronic transaction
       services.

     - OmniSky intends to co-market this package with wireless network carriers
       and Internet content providers in order to benefit from their brand
       recognition and marketing channels. OmniSky may also seek to bundle its
       service package with devices that are distributed by major national
       computer retailers.

     - OmniSky will seek to develop services that can access all platforms and
       devices, rather than committing to a single device or network protocol.

     - OmniSky is currently conducting a test program with approximately 6,800
       Palm V users to obtain feedback on its initial service offering. OmniSky
       expects to make this service commercially available in the second quarter
       of 2000.

     We have a 33% equity interest in OmniSky on a fully diluted basis in the
form of 10,000,000 shares of Series A Preferred Stock and 1,439,809 shares of
Series B Preferred Stock. We have a letter agreement with OmniSky to provide
engineering services through June 2000 for the design and development of
OmniSky's proposed system and services, and OmniSky has a perpetual,
royalty-free license to use our AIM software platform. Additionally, we have a
two-year right of first refusal to design and develop custom systems and
applications for all services relating to investment banking and brokerage
activities. We also have the right to bundle OmniSky services for a period of
five years as an added feature to the other services we offer at a monthly cost
to us of $3 per subscriber. We describe the details of our interest in OmniSky
in "Transactions Between Aether and Its Officers, Directors and Significant
Shareholders -- OmniSky" on page 70.

     Our chairman, chief executive officer and president, David S. Oros, is a
member of the OmniSky board of directors. Janice M. Roberts, one of our
directors, is also a director of OmniSky. Patrick McVeigh, former vice president
of worldwide sales for the Palm Computing division of 3Com, serves as president
and chief executive officer of OmniSky and also serves on the OmniSky board of
directors. OmniSky is based in Palo Alto, California.

OPERATIONS

  Engineering and Project Implementation

     Our most important operational resource is our engineering staff. This
staff includes wireless systems engineers, software engineers who specialize in
developing applications for handheld devices and engineers who specialize in
systems integration and testing. We have steadily built our engineering ranks
from ten in 1998 to 50 in February 2000, and with the acquisition of Riverbed we
will add 34 engineers. Many of our engineers come from engineering departments
at established companies, including IBM, Westinghouse Electric Corporation and
UPS/Roadnet. Seven of our engineers, including our chief technology officer,
comprise our research and development division. This group evaluates emerging
technologies and business opportunities and plays a key role in determining
which projects to pursue.

     Project implementation is critical to the effective delivery of services to
our customers. Projects generally consist of the following phases: project
definition, development, pilot testing, quality assurance and launch. Each
project has a project manager who works closely with the customer and
coordinates our engineers and our operations and marketing personnel through all
phases of the project. Our operations

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<PAGE>   201

staff prepares documentation and training manuals. During the product launch
phase, we send operations teams to train customer personnel on product use and
support. Our marketing department works closely with customers before commercial
launch to coordinate advertising and publicity.

  Technology and Network Operations

     We operate a secure network operations center at our headquarters in Owings
Mills, Maryland. We believe that this center is a vital component of our
wireless data service offerings and differentiates us from our competitors. By
outsourcing to us, our customers are relieved of the technology and operations
burden of managing a highly complex wireless data system. From our network
operations center, we maintain high speed data transmission lines (known as T1
connections) both to our customers' data sources and to the wireless data
networks we use. The center is equipped with Cisco and Hewlett-Packard
networking equipment, Sun Sparc UNIX servers and high-end clustered NT servers.
In the event of a power failure, we maintain backup power supplies, including
diesel-powered generators that are tested and serviced regularly. We believe our
network operations center is capable of meeting the security standards for
services we developed or are developing for our clients, who include Reuters,
Morgan Stanley Dean Witter Online and Charles Schwab. The center is staffed from
8:00 a.m. to 8:00 p.m. Eastern time on weekdays and is monitored 24 hours a day,
seven days a week. Through our acquisitions of Mobeo and LocusOne, we also
maintain network operation facilities in Bethesda, Maryland and Jacksonville,
Florida. We are planning to establish a backup facility in mid-2000.

     In December 1999, we established the WAP Enterprise Center. The center is
comprised of engineers who develop applications for WAP smartphones and the
systems to support data communication to these devices. The center currently is
developing WAP-enabled financial trading applications that will work with WAP
smartphones and is exploring WAP-based opportunities with wireless carriers, WAP
vendors and enterprise customers.

  Sales and Marketing

     We are expanding our sales and marketing efforts for our services in the
financial services and other industries as well as for software licensing. As of
February 2000, we had ten sales and marketing professionals. We intend to grow
this number significantly in the next 12 months, with sales and marketing
personnel focusing on each industry we pursue, as well as a dedicated sales and
marketing team for software licensing. Our business development personnel and
senior executives also spend a considerable amount of time developing potential
customer relationships and selling and promoting our services. We intend to
spend an estimated $25 million on a branding campaign in 2000 including print
and television advertising. Our current customer segments, the services we sell
to them and how we reach them are described below.

     - Individual investors and financial market professionals.  We believe
       individual investors are the primary subscribers to our wireless
       financial information and trading services, such as MarketClip and
       TradeRunner. Print advertising in finance-related publications is our
       primary means of marketing these services. Our strategy is to share
       marketing and advertising costs with our strategic partners and corporate
       customers associated with particular services. Our customer service
       center handles in-bound calls generated from these marketing efforts and
       signs up new subscribers. We also seek to develop relationships with
       financial institutions, whose market professionals become the end users
       of our services, such as F/X Alert. We market our products through direct
       sales executives in New York, Atlanta and Chicago and through occasional
       advertising in financial trade publications.

     - Companies that track inventory, deliveries and logistics.  We target
       sales of our e-Mobile Delivery service to companies that need to track
       the movement of their drivers and inventories across broad geographic
       areas on a real-time basis. Examples of customers include Physician Sales
       & Service, MAC Papers, Office Depot, NuCo2 and Suntory Water Group. We
       work with strategic partners, including Symbol Technologies, Intermec
       Technologies Corp. and BellSouth Wireless Data to

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<PAGE>   202

       market e-Mobile Delivery and maintain a staff of three sales and
       marketing professionals who are located in Richmond, Virginia, Boston,
       Massachusetts and Atlanta, Georgia. We plan to expand marketing efforts
       through direct mail and advertising to transportation logistics
       personnel.

     - Corporate software developers and independent software vendors.  We
       target as potential licensees of our AIM software platform large
       corporations with significant mobile workforce who wish to develop their
       own wireless applications, as well as software vendors and manufacturers
       of handheld devices. After our pending acquisition of Riverbed, we will
       target the same customer segments for the ScoutWare suite of mobile data
       management products. Each of our salespeople offer AIM licensing along
       with our full array of wireless data design, development and support
       services. In our experience, corporate customers who initially sought
       only to license our AIM software have often decided to purchase complete
       wireless data communications systems and services from us. Riverbed has a
       sales team of 29 dedicated to sales of its ScoutWare software and has
       licensed this software to Palm Computing, the U.S. Postal Service, Becton
       Dickinson, Oracle and others. After our acquisition of Riverbed, our
       combined sales forces will target independent software vendors for
       licensing of both AIM and ScoutWare through conferences, trade shows,
       vendor forums and trade advertising.

     - Engineering services clients.  As part of our business development
       effort, we seek out engineering assignments that might allow us to
       embrace technological advances or expand into new industry sectors or
       services.

  Product Fulfillment, Customer Service and Billing

     We provide product fulfillment, customer service and billing at our
customer service center, located at our headquarters. We maintain a modest
inventory of mobile devices and wireless modems, which we buy in bulk from
manufacturers and resellers. Our customer service representatives first verify
that a potential subscriber will have wireless network coverage where they plan
to use the service. For qualified subscribers, we load and configure custom
software on mobile devices, activate wireless modems and perform quality
assurance checks. We then pack, ship and track the product until the subscriber
receives it. For end users who already own a device, we provide only the modem
and software application. We handle all repair and warranty issues for devices
we provide to our subscribers.

     We train our customer service representatives to handle inquiries about our
services, device features and wireless communications. Our customer service
personnel are available weekdays from 8:00 a.m. until 8:00 p.m. Eastern time. We
currently employ ten customer service representatives and plan to triple that
number during the first half of 2000.

     We handle customer billing for all subscription fees, device and modem
purchases, securities exchange and market fees and other charges. We bill
monthly for subscriber services, which our non-corporate customers must pay by
credit card. As a result, our billing system can support increases in our
subscriber base. We intend to enhance our billing capabilities as our needs
grow.

STRATEGIC RELATIONSHIPS

     A key to our ability to provide complete wireless data services to our
customers is our relationships with third parties. These relationships take time
to develop, and we therefore believe they provide us with an advantage by
getting our services to market before our competitors. We maintain the strategic
relationships described below.

  Wireless Network Carriers

     We believe our relationships with wireless network carriers are mutually
beneficial. We believe we are among the largest buyers of wireless data network
capacity for many of the carriers we use. As a result, we are able to negotiate
favorable rates. Typically, we have one-year contracts to buy data network
capacity either for an agreed amount of kilobytes at a flat fee or on a
cents-per-kilobyte basis. We have contracts

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with Metrocall, AT&T Wireless Services, Bell Atlantic Mobile, BellSouth Wireless
Data, ARDIS, SBC Communications, Inc. and GTE Corp. As a result, we can give our
customers a wide variety of wireless carrier choices.

  Hardware and Software Vendors

     Our services increase the usefulness of wireless handheld devices, and we
believe our services will increase sales of these devices. Mobile device
manufacturers have therefore assisted us in various projects we have undertaken.
We have worked closely with 3Com, an Aether investor, on the development of our
wireless applications for the Palm personal organizer. In August 1999, a
subsidiary of Ericsson, one of the largest manufacturers of wireless phones,
agreed to assist us in developing services using WAP phones and next-generation,
high-speed GPRS data networks. In December 1999, we announced a strategic
alliance with Phone.com to jointly pursue corporate customers using Phone.com's
WAP browser technology for Web-enabled smartphones and our development and
service capabilities. We participate in industry development groups dedicated to
bringing new applications to wireless data, such as the Palm developers group,
the WAP Forum and the Windows CE developers forum.

  Financial Content Providers

     Financial content providers supply us with real-time financial information,
which we provide to our wireless data subscribers. Reuters, which is an Aether
investor, is our primary provider of financial information and market data for
MarketClip and TradeRunner. We have a license to use information from Reuters
with an initial term extending through August 2001, and the term automatically
extends each year after that unless we or Reuters decide to end the license. We
also have a license to use financial data from Bridge Information Systems
America, Inc., another financial content provider, and its subsidiary Telerate,
Inc. We have agreements with the New York Stock Exchange, the Nasdaq Stock
Market, Inc., the Chicago Board of Trade and the Options Price Reporting
Authority that authorize us to provide real-time price quotes.

RECENT DEVELOPMENTS

  Riverbed

     On February 9, 2000, we entered into a merger agreement to acquire Riverbed
for shares of our common stock. In the merger, we will issue 4,537,286 shares of
our common stock and convert existing options held by Riverbed employees into
options to acquire shares of our common stock. If all current Riverbed options
vest and are exercised, we would be obligated to issue 862,480 shares of our
common stock. As part of the transaction, we are holding in escrow 270,000 of
the shares payable to Riverbed shareholders for 12 months to secure their
post-closing indemnification obligations to us and we have agreed to indemnify
up to $40.5 million of damages the sellers may incur. The merger agreement
provided that we will appoint two persons named by Riverbed -- E. Wayne Jackson
and Robin T. Vasan -- to our board of directors when the acquisition closes.

     Upon the acquisition of Riverbed, the shareholders of Riverbed will become
parties to the registration rights agreement we entered into at the time of our
initial public offering with several of our shareholders, and the shareholders
of Riverbed will be deemed to have equivalent rights to the original holders and
their assignees. In addition, the shareholders of Riverbed, in the aggregate,
will have the right to one additional shelf registration after October 20, 2000,
or sooner if any of the original holders sell shares sooner pursuant to Rule
144. The additional shelf registration is limited to the number of shares a
holder could sell under Rule 144.

     The closing of the acquisition is subject to approval by the shareholders
of Riverbed (substantially all of whom have agreed to vote for the transaction),
continuation of the contracts between Riverbed and Palm Computing Inc., a
subsidiary of 3Com, and customary closing conditions, and is expected to occur
by March 15, 2000.

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  Reuters Strategic Alliance

     On February 8, 2000, we signed a letter of intent with Reuters to establish
a European wireless venture headquartered in the United Kingdom, which will be
initially focused on financial markets. The letter of intent provides that we
will acquire a 60% interest for $100 million and receive three of five board
seats. Dave Oros, our chief executive officer, will serve as chairman of the new
company and interim chief executive officer. The letter of intent is not binding
on us or Reuters and remains subject to definitive documentation and our
receiving money to fund the investment.

  Metrocall

     On February 8, 2000, we agreed to acquire for $10 million a 27.5% interest
in Inciscent in the form of Series A Preferred Stock. This newly-formed company
with Metrocall, PSINet, Hicks, Muse, Tate & Furst and other investors was formed
to develop wireless e-mail, Internet access and other applications for the small
office and home office market segments. Under the voting rights agreement,
Aether will have the right to appoint two of the seven directors of Inciscent.

     Upon the closing of our investment in Inciscent, we will receive
registration rights, including two demand registration rights that we can use
after the earlier of the third anniversary of closing or six months after an
initial public offering. The registration rights agreement will also grant us a
right of first offer on additional issuances of Inciscent securities.

     We will also enter into a co-sale agreement, which, among other things,
will require the holders of common stock to first offer any securities to
Inciscent and then to holders of at least 250,000 shares before selling the
securities to a third party and will further require all selling holders to
first offer their shares to holders of at least 250,000 shares. This agreement
will allow holders of at least 250,000 shares to sell a pro rata portion of
their stock to a third party along with the selling holders to the extent the
right of first refusal is not exercised. If holders of at least 66.7% of the
stock propose to sell their shares to a third party, these selling holders will
be able to force the remaining holders to participate in the sale. As part of
our closing obligations, we agreed to enter into a definitive services agreement
to provide Inciscent with a non-exclusive, perpetual, non-transferable license
to use our AIM software platform for $1 million, and also agreed to provide
technical consulting and development services billed on a time and materials
basis. As part of the investment we also agreed to acquire approximately 9.9% of
the outstanding capital stock of Metrocall for approximately $17 million.

  LocusOne

     On February 3, 2000, we acquired all of the capital stock of LocusOne for a
purchase price of $40 million, including the retirement of a line of credit and
payment of the legal fees of LocusOne. At closing, we paid $20 million in cash
and granted options to acquire 308,500 shares to existing LocusOne employees. At
the closing of this offering, we will be required to pay the former LocusOne
holders $5.4 million and place $13.6 million in escrow to pay all remaining
obligations, which will be paid on December 31, 2000. In connection with this
acquisition, the two principal stockholders of LocusOne have entered into
non-compete agreements with us expiring on the later of February 2, 2002 or ten
months after their termination with LocusOne.

  New Customers

     On January 12, 2000 we signed a definitive agreement with Response Services
Center, LLC to develop an emergency roadside assistance system.

     On December 28, 1999 we signed a non-binding memorandum of understanding
with TD Waterhouse to develop a wireless financial trading and information
service for its brokerage customers.

     On November 4, 1999, we signed a definitive agreement with National
Discount Brokers to provide its investors with wireless financial trading and
information services, including OmniSky e-mail and Internet access.
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     On October 11, 1999, we signed an engineering services contract with
Merrill Lynch to develop a wireless financial information service for use by its
financial professionals.

  Other Strategic Alliances

     On February 15, 2000 we entered into a non-binding memorandum of
understanding with Nextel to provide wireless data services using the Nextel
wireless communications network for mobile workforces in financial services,
transportation and other industries.

     On February 7, 2000 we entered into a non-binding letter of intent with
Proxicom, an Internet consulting and development company, to jointly pursue
opportunities to provide wireless data services to companies.

     On January 27, 2000 we signed a non-binding letter of intent with
CyberBills to develop a wireless electronic bill presentment and payment
service.

     On December 21, 1999 we announced an agreement to use "digital signature"
technology provided by Diversinet.

COMPETITION

     The market for our services is becoming increasingly competitive. We
believe we offer the broadest range of services to businesses necessary to
enable the development, offering and ongoing support of wireless data
communication systems for their employees or customers. The widespread adoption
of industry standards may make it easier for new market entrants to offer some
or all of the services we offer and may make it easier for existing competitors
to introduce some or all of the services they do not now provide, or improve the
quality of their services. We expect that we will compete primarily on the basis
of the functionality, breadth, quality and price of our services. Our current
and potential competitors include:

     - Wireless financial services providers, including W-Trade and 724
       Solutions;

     - Wireless communications software companies, including Phone.com, Nettech
       Systems Inc. and Dynamic Mobile Data;

     - Wireless data services providers, such as Wireless Knowledge, a joint
       venture of Microsoft and Qualcomm Incorporated, Research In Motion,
       GoAmerica and Saraide.com, which was recently acquired by Infospace.com;

     - Wireless systems integrators, such as IBM and GTE;

     - Wireless network carriers, such as AT&T Wireless Services, Bell Atlantic
       Mobile, Sprint PCS, Nextel Communications, Inc. and Metricom, Inc.; and

     - Mobile data management software providers, including Puma Technology,
       Inc., AvantGo, Inc. and Extended Systems, Inc.

     Many of our existing and potential competitors have substantially greater
financial, technical, marketing and distribution resources than we do.
Additionally, many of these companies have greater name recognition and more
established relationships with our target customers. Furthermore, these
competitors may be able to adopt more aggressive pricing policies and offer
customers more attractive terms than we can.

     Notwithstanding the increasing competitiveness of our market, we believe
that our potential competitors face substantial barriers to market entry.
Development of wireless data systems comparable to those we have already
developed is time consuming and costly. Moreover, the engineering talent
necessary to develop such systems is scarce.

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INTELLECTUAL PROPERTY RIGHTS

     We own applications for federal registration or common law rights in the
following trademarks: AirBroker(R), Aether Technologies(TM), Aether(TM) and our
logo, Wireless Solutions for a Portable Planet(TM) Portable Planet(TM) and
e-Mobile(TM). In addition, we own federal trademark registrations for
LocusOne(TM). We do not have any federal trademark registrations in the name
"Aether," "AIM" or "e-Mobile" and we may not be able to obtain such
registrations due to conflicting marks or for other reasons. We have been
informed that another party claims intellectual property in the mark e-Mobile.
Following our acquisition of Riverbed, we will also own applications for federal
registration or common law rights in the following trademarks: Riverbed
Technologies(TM), ScoutSync(TM), ScoutWeb(TM), ScoutWare(TM), ScoutIT(TM), Free
to Go Mobile(TM) and Solutions for the Mobile Enterprise(TM). Reuters and
Reuters MarketClip(TM) are the property of Reuters Group PLC. Morgan Stanley
Dean Witter Online TradeRunner(TM) is the property of Morgan Stanley Dean Witter
Online. This prospectus also includes trade dress, trade names and trademarks of
other companies. All other brand names or trademarks appearing in this
prospectus are the property of their respective holders.

     We rely on a combination of patent, copyright, trademark, service mark,
trade secret laws and contractual restrictions to establish and protect certain
proprietary rights in our services. We have applied for a patent on our AIM
platform, which addresses the technology employed to integrate various data
sources with wireless networks and devices. Mobeo has applied for two patents
for its technology. Specifically, one patent application covers the method and
system for providing formatted information via a two-way communication system.
The other patent application covers the method and system for providing
localized information. Riverbed has applied for a patent on its ScoutWare(TM)
technology, which relates to a system and method for synchronizing information
records between a remote device and a server in a computer network. There can be
no assurances that these applications will be granted or, if granted, that
holders of other patents will not claim that the patents infringe their patents.

     The steps taken by us to protect our intellectual property may not prove
sufficient to prevent misappropriation of our technology or to deter independent
third-party development of similar technologies. The laws of certain foreign
countries may not protect our services or intellectual property rights to the
same extent as do the laws of the United States. We also rely on certain
technologies that we and Mobeo license from third parties including data feeds
and related software from Reuters Select Feed Plus and Bridge Information
Services, synchronization technology from Riverbed and encoding technology from
Certicom. In addition, our ScoutWare software platform relies on a license of
Prism software by SpyGlass, Inc. These third-party technology licenses may not
continue to be available to us on commercially attractive terms. The loss of the
ability to use such technology could require us to obtain the rights to use
substitute technology, which could be more expensive or offer lower quality or
performance, and therefore have a material adverse effect on our business,
financial condition or results of operations.

     Third parties could claim infringement by us with respect to current or
future services. We expect that participants in our markets will be increasingly
subject to infringement claims as the number of services and competitors in our
industry segment grows. We have received two claims that we have infringed
patents developed by other parties. Although we believe these claims are without
merit, these and other intellectual property claims, with or without merit,
could be time-consuming and expensive to litigate or settle, could require us to
enter into costly royalty arrangements, could divert management attention from
administering our business and could preclude us from conducting our business.
Any such claim, whether meritorious or not, could be time-consuming, result in
costly litigation, cause service installation delays or require us to enter into
royalty or licensing agreements. Such royalty or licensing agreements might not
be available on terms acceptable to us or at all. As a result, any such claim
could have a material adverse effect upon our business, financial condition or
results of operations.

GOVERNMENT REGULATION

     We are not currently subject to direct federal, state or local government
regulation, other than regulations that apply to businesses generally. The
wireless network carriers we contract with to provide

                                       55
<PAGE>   207

airtime are subject to regulation by the Federal Communications Commission.
Changes in FCC regulations could affect the availability of wireless coverage
these carriers are willing or able to sell to us. We or OmniSky could also be
adversely affected by developments in regulations that govern or may in the
future govern the Internet, the allocation of radio frequencies or the placement
of cellular towers. Regulations of the SEC governing online trading could reduce
the level of online trading or the demand for wireless financial information.
Also, changes in these regulations could create uncertainty in the marketplace
that could reduce demand for our services or increase the cost of doing business
as a result of costs of litigation or increased service delivery cost or could
in some other manner have a material adverse effect on our business, financial
condition or results of operations.

     We currently do not collect sales or other taxes with respect to the sale
of services or products in states and countries where we believe we are not
required to do so. We do collect sales and other taxes in the states in which we
have offices and are required by law to do so. Some jurisdictions have sought to
impose sales or other tax obligations on companies that engage in online
commerce within their jurisdictions. A successful assertion by one or more
jurisdictions that we should collect sales or other taxes on our products and
services, or remit payment of sales or other taxes for prior periods, could have
a material adverse effect on our business, financial condition or results of
operations.

     Any new legislation or regulation, or the application of laws or
regulations from jurisdictions whose laws do not currently apply to our
business, could have an adverse effect on our business.

FACILITIES

     Our principal offices are located in Owings Mills, Maryland in a 35,018
square foot facility under a lease expiring in February 2010 with no renewal
option. We also lease an aggregate of 22,000 square feet for our offices in Boca
Raton, Florida, Jacksonville, Florida, Bethesda, Maryland, Portsmouth, New
Hampshire, New York, New York and Richmond, Virginia. Upon completion of the
acquisition of Riverbed, we will acquire an additional 22,048 square feet of
office space in Vienna, Virginia and Long Beach, California.

EMPLOYEES

     As of February 15, 2000, we had a total of approximately 153 employees, and
50 of these employees were engineers. Upon the completion of our acquisition of
Riverbed, we will add 100 employees, and 34 of these employees will be
engineers. None of our employees is covered by a collective bargaining
agreement. We believe that our relations with our employees are good.

LEGAL PROCEEDINGS

     We are not currently subject to any material legal proceedings. However, we
may from time to time become a party to various legal proceedings arising in the
ordinary course of our business.

                                       56
<PAGE>   208

                                   MANAGEMENT

EXECUTIVE OFFICERS AND DIRECTORS

     Our executive officers, directors and nominees for director, and their ages
and positions will be as follows after our acquisition of Riverbed:

<TABLE>
<CAPTION>
                NAME                   AGE                      POSITION
                ----                   ---                      --------
<S>                                    <C>   <C>
David S. Oros........................  40    Chairman, Chief Executive Officer and President
George M. Davis......................  43    President, Enterprise Solutions and Services
                                             Group
E. Wayne Jackson III(1)..............  38    President, Software Products Group and Director
David C. Reymann.....................  41    Chief Financial Officer
Dale R. Shelton......................  38    Chief Technology Officer
David K. Rensin(1)...................  28    Chief Scientist
Brian W. Keane.......................  41    Senior Vice President, Business Affairs
Mitch I. Selbiger....................  41    Senior Vice President, Marketing
J. Carter Beese, Jr.(2)(3)...........  43    Director
Frank A. Bonsal, Jr.(3)..............  63    Director
Mark D. Ein..........................  35    Director
Rahul C. Prakash(2)..................  38    Director
Janice M. Roberts....................  44    Director
Dr. Rajendra Singh...................  43    Director
George P. Stamas.....................  49    Director
Robin T. Vasan(1)....................  33    Director
Devin N. Wenig.......................  33    Director
Thomas E. Wheeler(2).................  53    Director
</TABLE>

- ---------------

(1) Messrs. Jackson and Vasan have been designated by Riverbed to become
    directors immediately after the completion of the acquisition of Riverbed.
    At the same time, Messrs. Jackson and Rensin will become officers of Aether.

(2) Member of the compensation committee.

(3) Member of the audit committee.

     David S. Oros founded Aether in 1996 and has been our chairman, chief
executive officer and president since Aether's inception. Mr. Oros also serves
on the board of directors of OmniSky. From 1994 until 1996, Mr. Oros was
president of NexGen Technologies, L.L.C., a wireless software development
company that contributed all of its assets to Aether. From 1992 until 1994, he
was president of the Wireless Data Group at Westinghouse Electric. Prior to
that, Mr. Oros spent from 1982 until 1992 at Westinghouse Electric directing
internal research and managing large programs in advanced airborne radar design
and development. Mr. Oros received a B.S. in mathematics and physics from the
University of Maryland and holds a U.S. patent for a multi-function radar
system.

     George M. Davis has served as our chief operating officer since September
1997 and will be appointed as president of our enterprise solutions and services
group at the closing of the Riverbed acquisition. He joined us in September 1996
as vice president, business development to lead initiatives required to launch,
maintain and develop business opportunities for our services. From September
1994 until September 1996, Mr. Davis was director of enterprise management
systems at Northrop Grumman Corp. Prior to that time, Mr. Davis spent more than
14 years at Westinghouse Electric where he managed advanced military electronic
development and production projects. He received a B.S. in business and
economics from Bethany College.

     E. Wayne Jackson III will become president of our software products group
and a director immediately after completion of the acquisition of Riverbed.
Since October 1998, Mr. Jackson has served

                                       57
<PAGE>   209

as the president and chief executive officer and a director of Riverbed, which
he co-founded with Mr. Rensin. From September 1994 until October 1997, Mr.
Jackson served as director of the emerging technologies division of Noblestar
Systems Corp. Riverbed was created by Noblestar in 1998. He received a B.S. in
business administration, finance, from James Madison University.

     David C. Reymann has served as our chief financial officer since joining us
in June 1998. Mr. Reymann is also responsible for our treasury management
services, investor relations and human resources. Before joining us, Mr. Reymann
was director of finance and accounting for The Sweetheart Cup Company from June
1996 until May 1998, where he managed the financial analysis department and the
accounting operations for 11 North American manufacturing plants. Prior to that,
Mr. Reymann spent 12 years with Procter & Gamble serving in several key finance,
accounting and operations positions. Prior to that, Mr. Reymann spent five years
at Ernst & Young where he most recently specialized in emerging growth
companies. Mr. Reymann received a B.S. in accounting from the University of
Baltimore and is a certified public accountant.

     Dale R. Shelton has served as our chief technology officer since February
2000. From June 1996 to February 2000, he served as our senior vice president,
engineering, during which time he directed the development of AIM and our
wireless data services. From January 1994 until June 1996, Mr. Shelton served as
the systems development leader for flash-flood prediction systems at the
National Weather Service. From June 1992 until January 1994, Mr. Shelton was
principal engineer for ARINC, Inc., where he led the development of aviation
tracking and maintenance systems. He received a B.S. in computer science from
the University of Maryland.

     David K. Rensin will become our chief scientist immediately after
completion of the acquisition of Riverbed. Since October 1998, he has served as
chief technology officer of Riverbed, which he co-founded with Mr. Jackson. From
July 1995 until 1998, Mr. Rensin managed the mobile convergent group at
Noblestar Systems Co. From January 1995 to July 1995, he was a senior programmer
at American Management Systems. Mr. Rensin received a B.S. in management science
and statistics from the University of Maryland.

     Brian W. Keane has served as senior vice president, business affairs since
joining us in August 1999. Mr. Keane is responsible for our mergers and
acquisitions, strategic investments, joint ventures and new strategic business
initiatives. From February 1998 until August 1999, Mr. Keane was chief financial
officer for Management Information Consulting, Inc., a technology consulting
company. Prior to that, Mr. Keane spent ten years as an investment banker with
Smith Barney Inc. Mr. Keane received a B.A. in history and mathematics from
Cornell University and an M.B.A. from Harvard Business School.

     Mitch I. Selbiger has served as our senior vice president, marketing since
January 2000. Mr. Selbiger is responsible for our advertising, branding,
marketing and public relations activities. From March 1999 until January 2000,
Mr. Selbiger served as vice president of marketing for OTG Software. Prior to
that, from July 1998 until March 1999, he served as vice president of marketing
for NetFactory. From August 1997 to July 1998, he served as director of eastern
area marketing for Netscape Communications, Inc. 1995 to 1997, he served as
director of government marketing for Sybase, Inc. Mr. Selbiger received a B.S.
in business administration from the University of Vermont and an M.B.A. from
George Washington University.

     J. Carter Beese, Jr. was elected a director of Aether on October 20, 1999.
Since July 1998, Mr. Beese has served as president of Riggs Capital Partners, a
division of Riggs National Corp., where he oversees a $100 million venture
capital fund. From September 1997 until July 1998, he served as vice chairman of
the Global Banking Group of BT Alex. Brown. Prior to the merger of Bankers Trust
and Alex. Brown, Mr. Beese was chairman of Alex. Brown International from
November 1994 until September 1997. From February 1992 until November 1994, Mr.
Beese served as a commissioner of the U.S. Securities and Exchange Commission.
Mr. Beese serves as a senior advisor to the Center for Strategic and
International Studies, a non-partisan public policy think tank and is involved
in the World Economic Forum. He serves as a director on the boards of China.com;
Internet Securities, Inc., a company majority owned by

                                       58
<PAGE>   210

Euromoney Institutional Investor, Inc.; and Natural Solutions, Inc. Mr. Beese
received a B.S. in economics and political science from Rollins College.

     Frank A. Bonsal, Jr. was elected a director of Aether on October 20, 1999.
Since 1978, Mr. Bonsal has been a founding partner of New Enterprise Associates,
one of the largest venture capital firms in the United States. Mr. Bonsal has
focused on the development of early stage companies. He currently serves as a
director on the boards of CARS, Inc., CORVIS Corp., Entevo Corp., Explore, Inc.,
GeneScreen, Inc. and Healthy Pet Inc. In addition, he is a special limited
partner of Amadeus Capital Partners, Boulder Venture, Novak Biddle, Trellis
Ventures and Windward Ventures. Mr. Bonsal received a B.A. in economics from
Princeton University.

     Mark D. Ein was a co-founder of Aether, and was elected a director of
Aether on October 20, 1999. Mr. Ein is the founder and chief executive officer
of Venturehouse Group, a holding company that was established in September 1999
to create, invest in and acquire technology and telecommunications companies.
From 1992 until September 1999, Mr. Ein was a principal with The Carlyle Group,
where he was responsible for many of its telecommunications investment
activities. Prior to joining Carlyle, Mr. Ein was an associate with Brentwood
Associates, where he worked on leveraged buyout and venture capital investments.
Prior to joining Brentwood Associates, he was an analyst in the real estate
department of Goldman, Sachs and Co. Mr. Ein currently serves as a director on
the boards of LCC International, Inc. and several private companies. Mr. Ein
received a B.S. in economics from the University of Pennsylvania and an M.B.A.
from Harvard Business School.

     Rahul C. Prakash was elected a director of Aether on October 20, 1999.
Since January 1997, Mr. Prakash has served as president of Telcom Ventures,
L.L.C., a wireless communications investment company. From January 1994 until
December 1996, Mr. Prakash served as vice president, business development of
Telcom Ventures. Prior to that time, he served as a director of business
development at LCC International, Inc., a worldwide provider of wireless
engineering and design services. From 1993 until 1994, Mr. Prakash was the
director of business development for Telemate, a joint venture he helped
establish between LCC and France Telecom. Mr. Prakash is also a director of
several private telecommunications companies controlled by Telcom Ventures. He
received an M.B.A. in international finance from American University and an
M.B.A. from the University of New Delhi, Faculty of Management Studies.

     Janice M. Roberts was elected a director of Aether on October 20, 1999.
Since September 1992, Ms. Roberts has served as senior vice president of global
marketing and business development for 3Com. She is also president of 3Com
Ventures, a corporate investment fund, and a director of OmniSky. From January
1992 until September 1992, Ms. Roberts served as vice president and general
manager for 3Com's enterprise networking division. From 1989 until January 1992,
Ms. Roberts was with BICC Communications where she held several positions,
including most recently, president and managing director of its worldwide data
networking business. Previously, she held a number of senior international
marketing, sales and business development positions in engineering, electronics
and communications-based companies. She holds an Honors degree in economics and
business from the University of Birmingham in the United Kingdom and is a member
of the Chartered Institute of Marketing.

     Dr. Rajendra Singh was elected a director of Aether on October 20, 1999.
Since December 1993, Dr. Singh has served as chairman of the board of directors
and chief executive officer of Telcom Ventures, L.L.C. From 1983 until June
1996, Dr. Singh served as chairman of the board of directors of LCC
International, Inc., which he co-founded with his wife in 1983. Dr. Singh has
played an instrumental role in the cellular industry by developing key standards
used today in wireless system design and methodology. Dr. Singh is a member of
the board of directors of Teligent, Inc. and XM Satellite Radio Holdings, Inc.
He received a Ph.D. in electrical engineering from Southern Methodist
University.

     George P. Stamas was elected a director of Aether on October 20, 1999.
Since January 2000, Mr. Stamas has served as a Vice Chair of DeutscheBanc Alex.
Brown. From April 1996 until December 1999, Mr. Stamas was a partner with the
law firm of Wilmer, Cutler & Pickering and now serves as a consultant to Wilmer,
Cutler & Pickering. From 1983 until April 1996, Mr. Stamas was a partner at
Piper
                                       59
<PAGE>   211

& Marbury L.L.P. Mr. Stamas is counsel to, and a limited partner of, the
Baltimore Orioles baseball team. Mr. Stamas also serves on the board of
directors of FTI Consulting, Inc., a provider of litigation support services,
and Luminant Worldwide Corporation, a provider of Internet consulting services.
He received a B.S. in economics from the Wharton School of the University of
Pennsylvania and a J.D. from University of Maryland Law School.

     Robin T. Vasan will be appointed as a director of Aether immediately after
completion of the acquisition of Riverbed. Since June 1998, Mr. Vasan has been a
general partner of Mayfield Fund, a venture capital fund. From June 1994 until
February 1997, he served as vice president, core technology of Risk Management
Solutions, an insurance software company. In 1997 and 1998, he attended Harvard
Business School. He received a B.A.S. in industrial engineering and economics
from Stanford University and an M.B.A. from Harvard Business School. Mr. Vasan
is a member of the board of directors of WebMethods, Inc., a
business-to-business infrastructure software and service company.

     Devin N. Wenig was elected a director of Aether on October 20, 1999. In
April 1994, Mr. Wenig joined Reuters America, Inc. and was promoted to executive
vice president of marketing in August 1998, where he is responsible for
marketing and business development for Reuters's information businesses in the
Americas. Mr. Wenig serves as a director on the boards of Loan Pricing Corp.,
Intralinks, Inc., FreeEdgar.com and Nastech Pharmaceutical Company, Inc. He
received a B.S. from Union College and a J.D. from Columbia University.

     Thomas E. Wheeler was elected a director of Aether on October 20, 1999.
Since 1992, Mr. Wheeler has served as president and chief executive officer of
the Cellular Telecommunications Industry Association. In 1994, Mr. Wheeler was
appointed by President Clinton to a six-year term as a member of the board of
trustees of the John F. Kennedy Center for the Performing Arts. Mr. Wheeler is a
director on the boards of the Public Broadcasting System and the U.S. Capitol
Historical Society. He received a B.S. in business administration from Ohio
State University.

     Following completion of the acquisition of Riverbed, our board will have
twelve directors. NexGen, Telcom-ATI Investors, L.L.C., Reuters and 3Com -- who
will together hold 55.1% of the shares of common stock outstanding after the
offering -- are parties to a stockholders agreement that governs voting for our
directors. The agreement requires each party to vote all its shares for two
directors named by NexGen, two directors named by Telcom-ATI Investors, two
directors named jointly by NexGen and Telcom-ATI Investors and one director
named by each of Reuters and 3Com. Messrs. Oros and Ein were appointed by
NexGen, Dr. Singh and Mr. Prakash were appointed by Telcom-ATI Investors, Mr.
Wenig was appointed by Reuters and Ms. Roberts was appointed by 3Com as
directors under the stockholder agreement. The terms of the stockholder
agreement are further described in "Transactions Between Aether and its
Officers, Directors and Significant Stockholders." Messrs. Jackson and Vasan
will be appointed directors of Aether when we acquire Riverbed, as required by
our acquisition agreement with Riverbed.

     Directors serve for a term of one year.

     Our executive officers are appointed by, and serve at the discretion of,
our board of directors. We expect that each of our officers will devote
substantially full time to our affairs. We expect that our non-employee
directors will devote such time to our affairs as is necessary to discharge
their duties. There are no family relationships among any of our executive
officers, directors or key employees.

COMMITTEES OF THE BOARD OF DIRECTORS

     The compensation committee consists of Messrs. Beese, Prakash and Wheeler.
The compensation committee:

     - determines the compensation of senior executive officers (such as the
       chief executive officer and chief financial officer), subject, if the
       board so directs, to the board's further ratification of the
       compensation;

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<PAGE>   212

     - determines the compensation for other officers or delegates such
       determinations to the chief executive officer;

     - grants options, stock or other equity interests under our stock option or
       other equity-based incentive plans; and

     - administers those plans and, where such plans specify, our other employee
       benefit plans.

     The audit committee consists of Messrs. Beese and Bonsal. The audit
committee:

     - makes recommendations to the board concerning the engagement of
       independent accountants;

     - reviews with the independent accountants the plans and results of the
       audit engagement;

     - approves professional services provided by the independent accountants;

     - considers the range of audit and non-audit fees;

     - verifies that auditors are independent of management and are objective in
       their findings;

     - reviews annual CPA audit and recommendations of internal controls and
       related management response;

     - reviews the audit reports with management and the auditor;

     - oversees the internal audit function; and

     - monitors management's efforts to correct deficiencies described in any
       audit examination.

DIRECTOR COMPENSATION

     Except for reimbursement for reasonable travel expenses relating to
attendance at board meetings and discretionary grants of stock options,
directors will not be compensated for their services as directors. Directors who
are employees will be eligible to participate in our equity incentive plan. We
have granted options to purchase 12,600 shares to each director and options to
purchase 4,000 shares to each member of the audit and compensation committees.
The exercise price of these options is equal to $16.00 per share. Mr. Wenig's
options are held in trust, and he currently has no beneficial interest in the
options.

     The following table identifies options that we have granted to non-employee
directors since January 1, 1997.

<TABLE>
<CAPTION>
                                         NUMBER OF
                                     SHARES UNDERLYING    EXERCISE
       NON-EMPLOYEE DIRECTOR            OPTIONS(#)        PRICE($)
       ---------------------         -----------------    --------
<S>                                  <C>                  <C>
J. Carter Beese, Jr. ..............       75,000           $ 0.40
                                          20,600            16.00
Frank A. Bonsal, Jr. ..............       37,500             1.77
                                          16,600            16.00
Mark D. Ein........................       17,500             4.00
                                          12,600            16.00
Rahul C. Prakash...................       16,600            16.00
Janice M. Roberts..................       12,600            16.00
Dr. Rajendra Singh.................       12,600            16.00
George P. Stamas...................        6,250             0.40
                                           5,000             2.40
                                          12,600            16.00
Devin N. Wenig.....................       12,600            16.00
Thomas E. Wheeler..................       37,500             1.77
                                          16,600            16.00
</TABLE>

                                       61
<PAGE>   213

EXECUTIVE COMPENSATION

     Summary Compensation.  The following table sets forth compensation for 1998
and 1999 awarded to, earned by or paid to our chief executive officer and the
four other most highly paid executive officers. We refer to these five officers
as the "named executive officers."

<TABLE>
<CAPTION>
                                                                       LONG-TERM
                                    ANNUAL COMPENSATION           COMPENSATION AWARDS
                               -----------------------------   -------------------------
                                                                                SHARES
                                                               OTHER ANNUAL   UNDERLYING     ALL OTHER
                                                               COMPENSATION    OPTIONS      COMPENSATION
 NAME AND PRINCIPAL POSITION   YEAR   SALARY ($)   BONUS ($)       ($)           (#)            ($)
 ---------------------------   ----   ----------   ---------   ------------   ----------    ------------
<S>                            <C>    <C>          <C>         <C>            <C>           <C>
David S. Oros................  1999    $200,000    $250,000           --       945,100             --
  Chairman, Chief Executive    1998     200,000     150,000           --            --             --
  Officer and President
George M. Davis..............  1999     157,292      24,504           --        55,000         $7,750
  President, Enterprise        1998     133,333      52,895       $2,420        75,000             --
  Solutions and Services
  Group
Dale R. Shelton..............  1999     129,167      20,000           --        42,500             --
  Chief Technology Officer     1998     109,200       4,000           --        50,000             --
David C. Reymann.............  1999     126,042          --           --        51,250             --
  Chief Financial Officer      1998      64,905          --           --        62,500             --
Brian W. Keane...............  1999      56,817      50,000           --       125,000             --
  Senior Vice President,       1998          --          --           --            --             --
  Business Affairs
</TABLE>

     Option Grants.  The following table shows information regarding stock
options granted to the named executive officers during the year ended December
31, 1999. No stock appreciation rights were granted to these individuals during
the year.

<TABLE>
<CAPTION>
                                                                                                   POTENTIAL REALIZABLE
                                            PERCENTAGE                                               VALUE AT ASSUMED
                                             OF TOTAL                                              ANNUAL RATES OF STOCK
                                             OPTIONS                                              PRICE APPRECIATION FOR
                        NUMBER OF SHARES     GRANTED     EXERCISE                                     OPTION TERM($)
                       UNDERLYING OPTIONS       TO       PRICE PER       EXPIRATION       ---------------------------------------
        NAME             GRANTED(#)(*)      EMPLOYEES    SHARE($)           DATE             0%(6)         5%(7)        10%(7)
        ----           ------------------   ----------   ---------   ------------------   -----------   -----------   -----------
<S>                    <C>                  <C>          <C>         <C>                  <C>           <C>           <C>
David S. Oros........       775,000(1)        28.04%      $ 1.60     June 22, 2009        $11,160,000   $18,958,293   $30,922,407
                            157,500(1)         5.70%      $ 4.00     September 20, 2009   $ 1,890,000   $ 3,474,814   $ 5,906,231
                             12,600(2)         0.46%      $16.00     October 20, 2009     $        --   $   126,785   $   321,298
George M. Davis......        50,000(1)         1.81%      $ 1.60     June 22, 2009        $   720,000   $ 1,223,116   $ 1,994,994
                              5,000(3)         0.18%      $ 8.00     September 26, 2009   $    30,000   $    74,023   $   141,562
Dale R. Shelton......        37,500(1)         1.36%      $ 1.60     June 22, 2009        $   540,000   $   917,337   $ 1,496,245
                              5,000(3)         0.18%      $ 8.00     September 26, 2009   $    30,000   $    74,023   $   141,562
David C. Reymann.....        18,750(1)         0.68%      $ 1.60     June 22, 2009        $   270,000   $   388,668   $   678,123
                             12,500(4)         0.45%      $ 8.00     October 11, 2009     $   100,000   $   225,779   $   418,748
                             20,000(3)         0.72%      $ 8.00     September 26, 2009   $   120,000   $   296,090   $   566,248
Brian W. Keane.......       125,000(5)         4.52%      $ 4.80     August 16, 2009      $   900,000   $ 1,843,342   $ 3,290,614
</TABLE>

- ---------------

 *  Options expire 90 days after the termination of employment of the option
    holder.

(1) The warrants are immediately exercisable in their entirety.

(2) Fifty percent of the options will become exercisable beginning on October
    20, 2000, and the other 50% will become exercisable on October 20, 2001.
    None of the options will become exercisable prior to such dates unless there
    is a change of control of Aether, which includes a sale of all our assets or
    the sale of at least 80% of the equity of our company.

(3) The options will become immediately exercisable in their entirety on
    September 26, 2001 and none of them will become exercisable prior to that
    date unless there is a change of control of Aether, which includes a sale of
    all our assets or the sale of at least 80% of the equity of our company.

                                       62
<PAGE>   214

(4) The options will become immediately exercisable in their entirety on October
    11, 2001 and none of them will become exercisable prior to that date unless
    there is a change in control of Aether, which includes a sale of all our
    assets or the sale of at least 80% of the equity of our company.

(5) One-third of the options are immediately exercisable. The remaining
    two-thirds of the options become exercisable annually over a two-year period
    in equal one-third increments, beginning on August 16, 2000.

(6) The options listed in this column were issued with an exercise price below
    the fair market value of the option at the time of issuance.

(7) The 5% and 10% assumed annual rates of compounded stock price appreciation
    are mandated by the SEC and are based on the assumption that the exercise
    price was the fair market value of the shares on the date of grant. Prior to
    October 20, 1999, the fair market value on the date of grant was determined
    by our board of directors. There is no assurance provided to any executive
    officer or any other holder of our securities that the actual price
    appreciation over the ten-year option term will be at the assumed 5% and 10%
    levels or at any other defined level.

     Aggregate Option Exercises and Holdings.  No options were exercised by the
named executive officers during the year ended December 31, 1999. The following
table provides information concerning the shares represented by outstanding
options held by each of the named executive officers as of December 31, 1999.

<TABLE>
<CAPTION>
                                                    NUMBER OF SHARES
                                                 UNDERLYING UNEXERCISED         VALUE OF UNEXERCISED
                                                   OPTIONS AT DEC. 31,         IN-THE-MONEY OPTIONS AT
                                                         1999(#)                 DEC. 31, 1999($)(1)
                                               ---------------------------   ---------------------------
                    NAME                       EXERCISABLE   UNEXERCISABLE   EXERCISABLE   UNEXERCISABLE
                    ----                       -----------   -------------   -----------   -------------
<S>                                            <C>           <C>             <C>           <C>
David S. Oros................................    932,500         12,600      $64,920,313    $  700,875
George M. Davis..............................    175,000         80,000      $12,404,375    $5,578,250
Dale R. Shelton..............................    150,000         67,500      $10,638,751    $4,715,187
David C. Reymann.............................     39,583         74,167      $ 2,774,115    $4,600,104
Brian W. Keane...............................     41,667         83,333      $ 2,784,375    $5,568,750
</TABLE>

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(1) Options were "in the money" because the closing price of Aether's common
    stock on December 31, 1999 exceeded the exercise price of the options. The
    value of unexercised options represents the difference between the exercise
    price of net options and $71.625, which was the last reported sale price of
    Aether common stock on December 31, 1999.

EMPLOYMENT AGREEMENTS WITH EXECUTIVE OFFICERS

     We have entered into employment contracts with Messrs. Oros and Reymann and
will enter an employment agreement with Mr. Jackson upon the closing of our
Riverbed acquisition.

     Mr. Oros' contract became effective June 22, 1999 and provides for a salary
of $200,000 per year, a performance bonus of up to $100,000 per year and
additional bonuses based on annual revenue targets and proceeds raised from
private placements of our equity securities in 1999. The contract has an initial
term expiring in June 2002 and automatically extends for additional one month
increments until terminated by Aether or Mr. Oros on 15 days notice. Pursuant to
the contract, we granted Mr. Oros a warrant to acquire 875,000 shares of our
common stock. The warrant currently has an exercise price of $1.60 per share of
common stock. We also gave Mr. Oros the right to allocate to key employees of
his choosing warrants to acquire 125,000 shares of common stock having the same
terms and conditions. Mr. Oros has awarded warrants for 50,000 shares of our
common stock to Mr. Davis, 37,500 shares of our common stock to Mr. Shelton and
18,750 shares of our common stock to Mr. Reymann. Mr. Oros subsequently received
our permission to assign part of his warrant, leaving him with a warrant to
acquire 775,000 shares. In September 1999, Mr. Oros received a warrant to
acquire 175,000 shares of our common stock at an exercise price of $4 per share.
From this grant, Mr. Oros subsequently assigned a warrant exercisable for

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17,500 shares of our common stock. If we terminate Mr. Oros without cause, he is
entitled to receive from us an amount equal to the salary he would have received
during the balance of the term of the employment contract, and his warrants will
fully vest immediately. Under the contract, "cause" means committing an act of
gross negligence or other willful act that materially adversely affects Aether,
refusing to comply in any respect with specific directions of our board of
directors, or being convicted or pleading no contest to any felony or any
misdemeanor involving fraud, breach of trust or misappropriation. Each of these
warrants became exercisable upon completion of our initial public offering.

     Mr. Reymann's contract was entered into June 1, 1999 and provides for a
minimum salary of $127,500 per year. The contract has an initial term expiring
on June 1, 2001. We and Mr. Reymann have agreed that if we terminate him without
cause, he is entitled to receive from us an amount equal to the salary he would
have received during the balance of the term of the employment contract.

     At the closing of the Riverbed acquisition, Mr. Jackson will enter into an
employment agreement to serve as president of our software products group. The
terms of the employment agreement have not yet been determined. We and Mr.
Jackson have agreed that if we terminate him without cause, he will be entitled
to receive from us an amount equal to six months of his base salary.

1999 EQUITY INCENTIVE PLAN

     Before our initial public offering, we adopted an equity incentive plan to
promote our long-term growth and profitability, improve stockholder value and
attract, retain and reward highly motivated and qualified employees and
directors. The compensation committee of our board of directors administers the
equity incentive plan unless the board of directors specifies another committee
of the board of directors or chooses to act itself as administrator. The board
of directors has given Mr. Oros authority as a special committee of the Board to
make option grants.

     Under the equity incentive plan, we can grant options for approximately 6.9
million shares of common stock (assuming completion of the Riverbed acquisition
and this offering), which number will adjust automatically to be 20% of our
outstanding common stock from time to time. We can grant options to employees in
the form of incentive stock options for up to 3,000,000 shares, but may choose
not to do so. Any options we grant that are not incentive stock options will be
nonqualified stock options.

     All of our employees, directors and certain service providers are eligible
to receive options under the equity incentive plan. For tax reasons, the equity
incentive plan limits the number of shares covered by the options that an
individual can receive in a calendar year to 50% of the original pool. The
administrator will determine the prices, exercise schedules, expiration dates
and other material conditions under which optionees may exercise their options.
The exercise price of these options may be less than the fair market value of
the common stock on the date of grant when the administrator considers that to
be appropriate. We replaced the options Aether Systems LLC granted with options
under this plan when we converted to a corporation before completion of our
initial public offering.

     All options will become exercisable if we have a change of control, except
as option agreements provide otherwise or as necessary to allow pooling of
interest accounting. The plan's administrator may provide that an optionee must
cooperate with us in connection with the change of control to receive this
acceleration. In general, we will have a change of control if:

     - anyone acquires or holds at least 80% of our voting securities, excluding
       holdings by our benefit plans and some other related parties;

     - we complete a merger or consolidation, unless, in general, our pre-merger
       shareholders own more than 20% of the voting securities of the merged
       companies;

     - our board changes in specified ways in connection with proxy contests or
       as a result of adding new directors who are not approved by existing
       directors; or

     - if we complete a liquidation or dissolution or sell or otherwise dispose
       of all or substantially all of our assets.
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In addition, unless we provide otherwise, or as necessary to allow pooling of
interest accounting, the equity incentive plan and all options will terminate in
defined circumstances if:

     - we are not the surviving company in a merger, consolidation or
       reorganization;

     - we complete a liquidation or dissolution or sell substantially all our
       assets; or

     - our board approves and we complete a transaction that results in a person
       or entity's owning all of our stock, unless the person or entity is
       related to us in specified ways.

However, before the equity incentive plan would terminate for one of those
reasons, we would either agree that our successor would assume the options
and/or the equity incentive plan, allow optionees to exercise the options if
these options were in-the-money, or cancel the options by paying the amount, if
any, by which the value determined with respect to that transaction exceeds the
exercise price of the options.

     The equity incentive plan limits the time during which an optionee can
exercise an option to no more than ten years. In addition, an optionee who
leaves employment will generally have no more than 90 days to exercise an
option, reduced to no days after employment in terminations for cause, and
additional rules apply to death and disability. The compensation committee may,
however, override the plan's rules, other than the ten year limit. We cannot
grant additional options under the equity incentive plan after September 20,
2009.

SENIOR BONUS PLAN

     We adopted a senior bonus plan before our initial public offering. A
special tax rule in Section 162(m) of the Internal Revenue Code of 1986, as
amended, limits the compensation that we can deduct for payments to our chief
executive officer and the four other most highly compensated executive officers
to $1 million per officer per year. We intend the senior bonus plan to provide
incentive compensation that does not count against each executive's deduction
limit. We may choose to use the senior bonus plan, or we may pay bonuses under
some other future plan to which the tax deduction limits will apply, as long as
we do not use the other payments to make up bonuses a participant loses under
the senior bonus plan.

     Unless our board of directors selects another committee, the compensation
committee administers the senior bonus plan and selects participants from our
key employees and those of any subsidiaries, although we expect that most
participants will be executive officers. When we refer to the "compensation
committee" in discussing the senior bonus plan, we also mean any other committee
that administers this plan. Only "outside directors" under the tax rules can
determine the participants, set the performance goals and certify that we or the
participants have met those goals. The compensation committee consists solely of
two outside directors and one director affiliated with a 5% stockholder. The
compensation committee has broad administrative authority to, among other
things, designate participants, establish performance goals and performance
periods, determine the effect of participant termination of employment and
"change in control" transactions before paying an award, and generally interpret
and administer the senior bonus plan. Neither we nor the board has designated
any participants or established any performance goals under the senior bonus
plan.

     The compensation committee will select participants for any given time
period based primarily on its judgment as to which executive officers are likely
to be named in our proxy statement as the chief executive officer or one of our
other four most highly compensated executive officers as of the end of the
performance period and that the compensation committee reasonably expects to
have compensation in excess of $1 million. None of our employees exceeded that
limit in 1999.

     In setting performance goals, the compensation committee will specify the
applicable performance criteria and targets it will use for such performance
period, which may vary from participant to participant.

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The performance criteria and targets will measure one or more of the following
company, subsidiary, operating unit or division financial performance measures:

     - pre-tax or after-tax net income or earnings;

     - earnings before interest expense, taxes, depreciation and amortization;

     - operating income or gross revenue;

     - profit or operating margin;

     - earnings per share;

     - stock price;

     - cash flows;

     - total stockholder return;

     - total stockholder return as compared to total return, on a comparable
       basis, of a publicly available index such as the Standard & Poor's 500
       Stock Index;

     - return on equity, on capital or on investment;

     - ratio of debt to stockholders' equity;

     - subscriber growth;

     - working capital; or

     - strategic business criteria consisting of one or more objectives based
       upon meeting specified revenue, market penetration, geographic business
       expansion goals, cost targets and goals relating to acquisitions or
       divestitures.

     The compensation committee may set these goals (1) on an absolute
stand-alone basis, or on a relative basis in comparison to others, (2) based on
internal targets, (3) based on comparison with prior performance, (4) based on
comparison to capital, shareholders' equity, shares outstanding, assets or net
assets, and/or (5) based on comparison to the performance of other companies.
For example, the compensation committee could express an income-based
performance measure in a number of ways, such as net earnings per share, or
return on equity or with reference to meeting or exceeding a specific target, or
with reference to growth above a specified level, such as prior year's
performance or peer group performance. The compensation committee can also
ignore unusual or nonrecurring accounting effects. The senior bonus plan
provides that achieving these goals must be substantially uncertain at the time
the goals are established and are subject to the committee's right to reduce the
amount of any award payable as a result of the performance as discussed below.

     The compensation committee may set a participant's target bonus, that is,
the amount the participant will receive if the targets are met, as a dollar
amount or in a formula, for example as a percentage share of a bonus pool,
provided that, if the committee uses a pool approach, the total bonus
opportunity for all participants who are part of the pool may not total more
than 100% of the pool. The committee has the sole discretion to reduce, but not
increase, the actual bonus awarded under the plan. The committee must determine
the extent to which the performance goals are met and the participant becomes
entitled to a bonus.

     The maximum bonus payable under the senior bonus plan to any one individual
in any one calendar year is $3 million, although we have no plans or
expectations at this time to pay bonuses of that size.

     Our board or the committee may at any time amend the senior bonus plan, and
our board may terminate the plan. However, without a participant's written
consent, no amendment or termination may materially adversely affect the annual
bonus rights, if any, of any already designated participant for a given
performance period after the participants and targets are set. Our board may
make any amendments necessary to comply with applicable regulatory requirements,
including the tax deduction limit for senior
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executives. If necessary to preserve the intended tax treatment, the board may
submit future amendments of the senior bonus plan to our shareholders for
approval.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

     None of the members of our compensation committee is an officer or employee
of Aether. None of our executive officers serves as a member of the board of
directors or compensation committee of any entity that has one or more executive
officers serving on our board of directors or compensation committee.

LIMITATION OF LIABILITY AND INDEMNIFICATION MATTERS

     Our certificate of incorporation limits the liability of directors to the
maximum extent permitted by Delaware law. Delaware law provides that a director
of a corporation will not be personally liable for monetary damages for breach
of an individual's fiduciary duties as a director except for liability:

     - for any breach of a director's duty of loyalty to Aether or to its
       stockholders;

     - for acts or omissions not in good faith or that involve intentional
       misconduct or a knowing violation of law;

     - for unlawful payments of dividends or unlawful stock repurchases or
       redemptions as provided in Section 174 of the Delaware General
       Corporation Law; or

     - for any transaction from which a director derives an improper personal
       benefit.

     Our bylaws provide that Aether will indemnify its directors and executive
officers and may indemnify its officers, employees and other agents to the full
extent permitted by law. We believe that indemnification under our bylaws will
cover at least negligence and gross negligence on the part of an indemnified
party. Our bylaws also permit us to advance expenses incurred by an indemnified
party in connection with the defense of any action or proceeding arising out of
a party's status or service as a director, officer, employee or other agent of
Aether upon an undertaking by the party to repay the advances if it is
ultimately determined that he or she is not entitled to indemnification.

     We entered into separate indemnification agreements with each of our
directors and officers. These agreements require us to, among other things,
indemnify the director or officer against expenses (including attorney's fees),
judgments, fines and settlements paid by the individual in connection with any
action, suit or proceeding arising out of the individual's status or service as
a director or officer of Aether (other than liabilities arising from willful
misconduct or conduct that is knowingly fraudulent or deliberately dishonest)
and to advance expenses incurred by the individual in connection with any
proceeding against the individual with respect to which he or she may be
entitled to indemnification by us.

     We believe that our certificate of incorporation and bylaw provisions and
indemnification agreements are necessary to attract and retain qualified persons
as directors and officers. We also maintain directors' and officers' liability
insurance.

     At present we are not aware of any pending litigation or proceeding
involving any director, officer, employee or agent of Aether where
indemnification will be required or permitted. Furthermore, we are not aware of
any threatened litigation or proceeding that might result in a claim for
indemnification.

     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers or persons controlling our company
pursuant to the foregoing provisions, we have been informed that, in the opinion
of the SEC, such indemnification is against public policy as expressed in the
Securities Act and is therefore unenforceable.

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                      TRANSACTIONS BETWEEN AETHER AND ITS
                OFFICERS, DIRECTORS OR SIGNIFICANT STOCKHOLDERS

     Since January 1, 1997, we have engaged in the following transactions with
executive officers, directors and owners of 5% or more of our equity, or
entities related to them.

EQUITY INVESTMENTS

     The following discussion describes the issuance of equity interests in
connection with the initial capitalization of our predecessor, Aether Systems,
LLC, and subsequent financings. Immediately prior to our initial public offering
on October 26, 1999, we converted into a Delaware corporation at which time,
each holder of units in our limited liability company was converted into two and
one-half shares of our common stock and each option or warrant for one unit was
converted into an option or warrant for two and one-half shares of our common
stock. The discussion below gives only the number of shares into which units
were converted.

     Aeros L.L.C., our predecessor, was formed in January 1996 by NexGen
Technologies, L.L.C. and a predecessor to Transettlements, Inc. At the time
Aeros was formed, NexGen contributed assets in the wireless data field in
exchange for 7,500,000 shares and Transettlements contributed $1,000,000 in cash
in exchange for 2,500,000 shares. In May 1996, Transettlements contributed an
additional $500,000 in exchange for an additional 1,250,000 shares. In August
1996, we changed our name to Aether Technologies International, L.L.C. Then, in
September 1999, we changed our name to Aether Systems, LLC.

     In February 1997, a subsidiary of Telcom Ventures, L.L.C. acquired 725,000
shares from Transettlements and 107,500 shares from NexGen and contributed
$1,000,000 to Aether in exchange for 1,562,500 shares. Additionally, Telcom
Ventures was granted an option to purchase 1,775,000 shares from Transettlements
and two options to purchase a total of 2,267,500 shares from NexGen. In December
1997, Telcom Ventures and its subsidiary contributed an additional $690,369 to
Aether in exchange for an additional 575,308 shares. In June 1999, Telcom
Ventures exercised its option with Transettlements and one of its options with
NexGen to purchase 1,775,000 and 392,500 shares, respectively. Aether did not
receive any proceeds from the exercise of these options.

     In October 1997, we borrowed $100,000 from Reuters Group Overseas Holdings
(UK) Limited pursuant to a demand note that accrued interest at 7% per year. In
January 1998, we borrowed an additional $100,000 from Reuters at an accrued
interest rate of 7% per year pursuant to a second demand note. In March 1998, as
part of the consideration paid by Reuters for Aether's development of
MarketClip, Reuters cancelled both of these notes.

     In January 1998, Pyramid Ventures, Inc., a subsidiary of Bankers Trust
Corporation, acquired 833,333 shares at $1.20 per share and 1,004,903 shares at
$1.49 per share for total proceeds to Aether of approximately $2.5 million. At
that time, Aether redeemed 208,333 shares held by NexGen for $249,999 and
625,000 shares held by Transettlements for $750,000. As part of the financing
arrangement, Pyramid agreed to use reasonable efforts (1) to cause BT Alex.
Brown to purchase 100 subscriptions to MarketClip for a 12-month period or (2)
to refer affiliates of BT Alex. Brown or third parties to Aether for the purpose
of entering into development contracts with an aggregate price of $300,000 over
a two-year period.

     In June 1998, Telcom Ventures and Pyramid each loaned us $250,000. The
notes accrued interest at 8% per year and were due on demand with a stated
maturity date of the earlier of December 31, 1998 or the closing of an
anticipated private placement of units. The notes were convertible into shares
at the option of the holder at the rate of $250,000 divided by the per share
price to be paid in the anticipated private placements. In connection with the
issuance of these notes, we also issued warrants to acquire 14,140 shares with
an exercise price of $0.01 per share to each of Telcom Ventures and Pyramid.
Pyramid converted its $250,000 loan plus accrued interest in August 1998 to
142,950 shares at a per share price of $1.77 and exercised its warrant and
acquired 14,140 shares. In August 1998, we repaid the amount owed

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Telcom Ventures, including $2,520 in interest. In August 1999, Telcom Ventures
exercised its warrant and acquired 14,140 shares at a per share price of $0.01.

     In August 1998, Reuters received 2,828,055 shares in exchange for
$4,735,020 in cash and forgiveness of $530,980 we owed Reuters for hardware and
other inventory, offset by $266,000 Reuters owed us under a license agreement we
previously entered into with Reuters relating to sales of MarketClip and related
fees.

     In October 1998, 3Com Corp. contributed $6,000,000 in exchange for
2,500,000 shares. At the same time, we issued 3Com a conditional warrant to
purchase 893,665 shares exercisable at $0.01 per share if the milestones
described below are achieved before October 20, 2001. 3Com achieved the first
milestone entitling it to exercise 143,665 shares as a result of having
completed a joint sales and marketing plan. 3Com may exercise an additional
375,000 shares if and when we receive $6 million in engineering services revenue
from business opportunities introduced by 3Com. 3Com may exercise an additional
375,000 shares if we attain 6,000 wireless service subscribers as a result of
business opportunities introduced to us by 3Com. 3Com has not attained either of
these last two milestones and has not exercised any of its warrants.

     Effective June 1999, we issued to Mr. Oros a warrant to acquire 875,000
shares at an exercise price of $.01 per share. We subsequently agreed with Mr.
Oros to amend the exercise price to $1.60 per share. We also gave Mr. Oros the
right to allocate to key employees of his choosing warrants to acquire 125,000
shares having the same terms and conditions. Mr. Oros has awarded warrants to
acquire 50,000 shares to Mr. Davis, 37,500 shares to Mr. Shelton and 18,750
shares to Mr. Reymann. Mr. Oros subsequently received our permission to
subdivide his warrant to give Mark Ein a warrant to acquire 100,000 shares,
leaving Mr. Oros with a warrant to acquire 775,000 shares. In September 1999,
when we increased the exercise price on the warrants issued to Mr. Oros in June
1999, we granted Mr. Oros a warrant to acquire an additional 175,000 shares at
an exercise price of $4 per share to compensate him for the increase in the
exercise price on the earlier warrants. From this grant, Mr. Oros subsequently
assigned a warrant exercisable for 17,500 shares to Mr. Ein.

     In August 1999, we issued to Mr. Ein 100,000 shares upon exercise of his
options at an exercise price of $0.40 per share. In September 1999, Mr. Beese
exercised an option for 75,000 shares at an exercise price of $0.40 per share.

     NexGen, Telcom-ATI Investors, Reuters and 3Com entered into a stockholder
agreement under which these parties vote for two directors named by each of
NexGen and Telcom-ATI Investors and for one director named by each of Reuters
and 3Com. In addition, commencing on the date of the first annual meeting of
stockholders, if the board of directors consists of up to nine members, these
parties will vote to elect to the board of directors one additional person named
jointly by NexGen and Telcom-ATI Investors Ventures; and if the board of
directors consists of 10 or more members, the parties will vote to elect two
members named jointly by NexGen and Telcom-ATI Investors. In connection with the
acquisition of Riverbed, these stockholders will amend the stockholder agreement
to allow for a board of 12 members. The right to name directors will end when
parties to the agreement reduce their share ownership below levels set forth in
the agreement.

     We entered into a registration rights agreement with NexGen, Telcom-ATI
Investors, Reuters, 3Com and Transettlements, which entitles these parties to an
aggregate of three demand registrations at any time after October 27, 2000, and
at the request of these parties, to include in any registration statement for
our own account or the account of any other stockholder, the shares of common
stock held by those parties, subject to limitations set forth in the agreement.
The agreement also requires us to file a shelf registration statement covering
the sale of all shares held by parties to the stockholder agreement from time to
time. The agreement requires us to file the shelf registration statement only
when we are eligible to use the short form registration statement on Form S-3,
which would be no earlier than October 20, 2000. Upon the acquisition of
Riverbed, the shareholders of Riverbed will become parties to this registration
rights agreement under which the shareholders of Riverbed and their assignees
will have equivalent rights to the original holders and their assignees
thereunder. In addition, the shareholders of Riverbed and their assignees, in
the aggregate, will have the right to one additional shelf registration after
October 20, 2000
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(or earlier if the original holders sell shares in reliance on Rule 144)
provided that the sales by any Riverbed shareholder or assignee under such
additional right will not exceed the amount that would be permitted under Rule
144(e) if the one year holding period had expired.

LOAN TO NEXGEN

     In September 1998, we loaned NexGen $155,000 at an interest rate of 7.5%
per year pursuant to two notes. One note for $95,000 was due in December 1998,
and one note for $60,000 was due in October 1998. In August 1999, both notes
were amended to be due upon 30 days notice. On December 24, 1998, NexGen made a
payment of $19,346 with respect to these notes. On February 15, 2000, NexGen
made an additional payment of $151,716 in full satisfaction of the notes.

REUTERS LICENSE AGREEMENT

     In August 1998, we entered into an amended license, marketing and
distribution agreement with Reuters, which continues through August 11, 2001 and
renews automatically for successive one-year terms unless either party provides
180 days prior written notice. Reuters granted us a non-exclusive license to use
the information supplied by Reuters Selectfeed Plus for distribution to
subscribers of MarketClip, AirBroker and for development purposes. In August
1999, Reuters granted us permission to use Selectfeed Plus information for the
TradeRunner service developed for Morgan Stanley Dean Witter Online and other
services we are developing. Pursuant to the agreement, Aether granted Reuters an
exclusive license to use the systems developed by Aether to transmit Reuters
information to wireless handheld devices and a license to use the MarketClip
software for purposes of supplying subscribers with MarketClip. The geographic
scope of all of the licenses under the agreement is limited to the United
States. Under the agreement, Reuters has a right of first refusal to purchase
shares of Aether if Aether or any stockholder sells shares and, as a result, a
competitor of Reuters holds 50% or more of our shares, or if we sell all or
substantially all of our assets to a competitor of Reuters. Under the terms of
the license, we pay Reuters a monthly fee for each subscriber to our services
that uses information provided by Reuters. During 1998 we paid Reuters $40,300
under this contract and the average monthly fee per subscriber was $4.89; during
1999 we paid Reuters $122,356 under this contract and the average monthly fee
per subscriber was $8.02.

OMNISKY

     On August 9, 1999, we formed a new company with 3Com in which we acquired
an interest in AirWeb Corporation, which was doing business as OpenSky and is
currently known as OmniSky Corporation. We contributed a perpetual,
non-exclusive, non-assignable, royalty-free worldwide license to our AIM
software platform in exchange for 7,000,000 shares of Series A Preferred Stock.
In connection with the formation of OmniSky, 3Com paid $7.0 million in cash and
agreed to contribute to OmniSky a perpetual, non-exclusive, non-assignable
license to 3Com's Web Clipping technology (including rights to derivative works)
and Palm OS software in exchange for 10,000,000 shares of Series A Preferred
Stock, which initially represented a 33% equity interest in OmniSky on a fully
diluted basis. The management team of OmniSky acquired in the aggregate 4.2
million shares of common stock and options to acquire an additional 5.8 million
shares. Following our initial public offering, we exercised a warrant to acquire
an additional 3,000,000 shares of Series A Preferred Stock for $2,500,000
increasing our equity interest in OmniSky to 33% on a fully diluted basis. In
January 2000, we exercised our right of first refusal to maintain our 33% equity
interest by acquiring 1,439,809 shares of Series B Preferred Stock for $6.7
million, net of the cancellation of approximately $613,000 of indebtedness owed
by OmniSky to us. 3Com did not exercise its right of first offer and thus its
33% interest has been diluted.

     As part of our investment with 3Com in OmniSky, we each received
registration rights, including two demand registration rights that we can use
after the earlier of the completion of OmniSky's initial public offering and
August 9, 2004. We also entered into a right of first refusal and co-sale
agreement, which, among other things, requires the management team to first
offer any OmniSky securities to OmniSky and then to us and 3Com before selling
the securities to a third party. This agreement also allows us and 3Com to sell
a pro rata portion of our stock to a third party along with the management team
if the right
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of first refusal is not exercised. We and 3Com have also agreed that before
either of us sells any shares of Series A Preferred Stock to an unrelated third
party, we would first offer the other (or any other holders of Series A
Preferred Stock) those shares on a pro rata basis and then offer their shares to
OmniSky.

     Aether, 3Com and OmniSky's management are each entitled to appoint one
director to OmniSky's board of directors. OmniSky's board of directors currently
includes: David S. Oros, our chairman, chief executive officer and president and
Janice M. Roberts, who is one of our directors. We have entered into a voting
agreement with 3Com and OmniSky's management in which each of the parties has
agreed to vote in favor of each of the directors named by Aether, 3Com and
OmniSky's management until the earliest of (1) OmniSky's completion of an
initial public offering of at least $15 million, (2) OmniSky's completion of a
sale of substantially all of the assets of OmniSky or the transfer of more than
50% of the voting power of OmniSky or (3) the parties' termination of the
agreement. OmniSky cannot take certain major corporate actions, such as selling
the company or issuing securities with rights and preferences senior to the
Series A Preferred Stock, without the approval of holders of two-thirds of the
Series A Preferred Stock.

     On August 9, 1999, we entered into a letter agreement with OmniSky under
which we have agreed to provide OmniSky, for a period of ten months from the
date of the letter agreement, engineering services for the design and
development of its proposed systems and services. The letter agreement
originally provided that OmniSky will pay us $250,000 per month for these
services but we subsequently amended it to be on a time and materials basis. In
addition, they paid us $500,000 for work performed prior to the date of the
letter agreement. Additionally, for a period of five years from the date of the
letter agreement, OmniSky has agreed to provide us the right to resell OmniSky's
basic package of services. We also have a right of first refusal for development
of all investment banking and brokerage applications for OmniSky for a period of
two years from the date of the letter agreement, subject to approval of the
company for whom the service is developed.

     In October 1999, we agreed to purchase 25,000 Minstrel V modems from
OmniSky for a price per modem of $230, which was OmniSky's cost. OmniSky has an
exclusive buying arrangement with Novatel for Minstrel V modems, which runs
through March 2000. We have paid for 20,000 of the 25,000 modems in two
installments: $1,400,000 on October 15, 1999 and $3,200,000 on November 15,
1999. The modems are being delivered to us through April of 2000.

RIVERBED

     On February 9, 2000, we entered into a merger agreement with Riverbed for
an aggregate of 5.4 million shares of our common stock. We agreed to issue
4,537,286 million shares in exchange for the outstanding shares of Riverbed
capital stock and to reserve an additional 862,480 shares of our common stock
for issuance upon exercise of options issued to Riverbed employees. Immediately
after the closing, E. Wayne Jackson, the chairman and chief executive officer of
Riverbed, will become the president of our software products group and a
director of Aether and Robin T. Vasan, a director of Riverbed, will become a
director of Aether. In addition, Mr. Jackson will enter into an employment
agreement which includes a provision restricting him from competing with us or
Riverbed, for one year following his termination. As part of the closing,
licensing fees for our AIM software platform that have been incurred by Riverbed
will no longer be payable.

REUTERS

     On February 8, 2000, we entered into a letter of intent with Reuters under
which we will contribute $100 million for 60% of a new European company. Under
the letter of intent, Reuters will own the remaining 40% through a contribution
of assets and $22 million in cash. David S. Oros, our chief executive officer,
will serve as chairman and interim chief executive officer of the new company.
This letter of intent is non-binding, and there is no assurance that we will
successfully complete definitive documentation with respect to this transaction.

                                       71
<PAGE>   223

                             PRINCIPAL STOCKHOLDERS

     The following table sets forth certain information with respect to
beneficial ownership of our common stock as of February 15, 2000 (assuming
completion of the Riverbed acquisition), and as adjusted to reflect the sale of
2,346,219 shares of common stock offered in the concurrent common stock offering
(assuming no exercise of the over-allotment option) and the closing of the
Riverbed acquisition, as to:

     - each person (or group of affiliated persons) known by us to own
       beneficially more than 5% of our outstanding common stock;

     - each stockholder selling shares of our common stock in the concurrent
       common stock offering;

     - each of our directors and persons we have identified will become
       directors;

     - each of the executive officers named in the summary compensation table;
       and

     - all our directors and executive officers as a group.

     Except as indicated in the footnotes to this table and under applicable
community property laws, to our knowledge, the persons named in the table have
sole voting and investment power with respect to all shares of common stock.
Options exercisable on or before April 30, 2000, are included as shares
beneficially owned. For the purposes of calculating percent ownership as of
February 15, 2000, 34,509,687 shares were issued and outstanding (assuming
completion of the Riverbed acquisition) and, for any individual who beneficially
owns shares represented by options exercisable on or before April 30, 2000,
these shares are treated as if outstanding for that person, but not for any
other person. Unless otherwise indicated, the address of each of the individuals
and entities named below is: c/o Aether Systems, Inc., 11460 Cronridge Drive,
Owings Mills, Maryland 21117.

<TABLE>
<CAPTION>
                                         BENEFICIAL OWNERSHIP OF      SHARES TO BE     BENEFICIAL OWNERSHIP OF
                                      SHARES BEFORE THE CONCURRENT      SOLD IN      SHARES AFTER THE CONCURRENT
                                          COMMON STOCK OFFERING        CONCURRENT       COMMON STOCK OFFERING
                                      -----------------------------   COMMON STOCK   ---------------------------
          NAME AND ADDRESS               NUMBER           PERCENT      OFFERING**       NUMBER        PERCENT
          ----------------            -------------      ----------   ------------   ------------   ------------
<S>                                   <C>                <C>          <C>            <C>            <C>
DIRECTORS AND EXECUTIVE OFFICERS:
David S. Oros(1)....................    7,724,168           23.6%          30,000      7,524,376          21.9%
George M. Davis(2)..................      175,000               *          30,000        145,000              *
Dale R. Shelton(3)..................      150,000               *          30,000        120,000              *
David C. Reymann....................       39,583               *          15,000         24,583              *
Brian W. Keane......................       41,667               *          15,000         26,667              *
David K. Rensin.....................      204,780               *           5,119        199,661              *
  c/o Riverbed Technologies, Inc.
  2070 Chain Bridge Road
  Vienna, VA 22182
Mitch I. Selbiger...................            0               *               0              0              *
Frank A. Bonsal, Jr.(4).............       42,250               *               0         42,250              *
  1119 St. Paul Street
  Baltimore, MD 21202
J. Carter Beese(5)..................       77,500               *               0         77,500              *
Mark D. Ein(6)......................      217,500               *               0        217,500              *
E. Wayne Jackson III................      195,862               *          24,897        170,965              *
  6608 Corine Court
  Columbia, MD 21044
Rahul C. Prakash(7).................        2,000               *               0          2,000              *
  c/o Telcom Ventures, L.L.C.
  211 N. Union St., Suite 300
  Alexandria, VA 22314
Janice M. Roberts(8)................            0               *               0              0              *
  c/o 3Com Corporation
  5400 Bayfront Plaza
  Santa Clara, CA 95952
</TABLE>

                                       72
<PAGE>   224

<TABLE>
<CAPTION>
                                         BENEFICIAL OWNERSHIP OF      SHARES TO BE     BENEFICIAL OWNERSHIP OF
                                      SHARES BEFORE THE CONCURRENT      SOLD IN      SHARES AFTER THE CONCURRENT
                                          COMMON STOCK OFFERING        CONCURRENT       COMMON STOCK OFFERING
                                      -----------------------------   COMMON STOCK   ---------------------------
          NAME AND ADDRESS               NUMBER           PERCENT      OFFERING**       NUMBER        PERCENT
          ----------------            -------------      ----------   ------------   ------------   ------------
<S>                                   <C>                <C>          <C>            <C>            <C>
Dr. Rajendra Singh(9)...............    7,026,948             22%               0      6,851,274          19.9%
  c/o Telcom Ventures, L.L.C.
  211 N. Union St., Suite 300
  Alexandria, VA 22314
George P. Stamas(10)................       11,250               *           5,000          6,250              *
  c/o DeutscheBanc Alex. Brown
  One South Street
  Baltimore, MD 21202
Robin T. Vasan(11)..................            0               *               0              0              *
  c/o Mayfield Fund
  2800 Sand Hill Road
  Menlo Park, CA 94025
Devin N. Wenig......................            0               *               0              0              *
  c/o Reuters America, Inc.
  1700 Broadway, 2nd Floor
  New York, NY 10019
Thomas E. Wheeler(12)...............       47,500               *               0         42,500              *
All directors and executive officers
  as a group
  (18 persons)(13)..................   15,956,006           49.8%         500,507     15,455,499          43.0%
5% STOCKHOLDERS:
3Com Corporation(14)................    2,643,665            8.2%               0      2,643,665           7.7%
  5400 Bayfront Plaza
  Santa Clara, CA 95052
NexGen Technologies, L.L.C..........    6,791,668           21.2%         169,792      6,621,876          19.3%
Pyramid Ventures, Inc.(15)..........    1,995,325            6.2%          49,883      1,945,442           5.7%
  One Bankers Trust Plaza
  130 Liberty Street
  New York, NY 10006
Reuters MarketClip Holdings             2,828,055            8.8%               0      2,828,055           8.2%
  Sarl(16)..........................
  c/o Reuters America, Inc.
  1700 Broadway, 2nd Floor
  New York, NY 10019
Telcom-ATI Investors, L.L.C.(17)....    7,026,948           20.7%         175,674      6,851,274          19.9%
  211 N. Union St., Suite 300
  Alexandria, VA 22314
</TABLE>

- ---------------
  *  Less than 1%.

**  Shares set forth in this column are shares to be sold by the person named
    and do not include shares over which the named person has indirect
    beneficial ownership.

 (1) Includes 6,791,668 shares owned by NexGen Technologies, L.L.C. over which
     Mr. Oros exercises voting and investment control by virtue of his position
     as Managing Member of NexGen. Also includes warrants to purchase 932,500
     shares of common stock.

 (2) Includes vested options to purchase 125,000 shares of common stock and
     warrants to purchase 50,000 shares of common stock.

 (3) Includes vested options to purchase 112,500 shares of common stock and
     warrants to purchase 37,500 shares of common stock.

 (4) The amount shown excludes approximately 18,170 shares in which Mr. Bonsal
     has an indirect interest as a result of his non-voting limited liability
     company membership interest in Telcom-ATI

                                       73
<PAGE>   225

     Investors and excludes the indirect interest Mr. Bonsal has in 6,713 shares
     Telcom-ATI Investors has the right the acquire.

 (5) The amount shown excludes approximately 103,825 shares in which Mr. Beese
     has an indirect interest as a result of his non-voting limited liability
     company membership interest in Telcom-ATI Investors and excludes the
     indirect interest Mr. Beese has in 38,355 shares Telcom-ATI Investors has
     the right to acquire.

 (6) Includes warrants to purchase 100,000 shares of common stock and warrants
     to purchase 17,500 shares of common stock at $4 per share.

 (7) Mr. Prakash, the president of Telcom-ATI Investors, (which is controlled by
     Telcom Ventures, LLC), disclaims beneficial ownership of the 5,151,948
     shares owned by Telcom-ATI Investors including approximately 52,000 shares
     in which he has an indirect interest as a result of his option to acquire a
     non-voting limited liability company membership interest in Telcom-ATI
     Investors and the indirect interest Mr. Prakash has in approximately 19,000
     shares Telcom-ATI Investors has the right to acquire.

 (8) Ms. Roberts is senior vice president global marketing and business
     development of 3Com Corp. and president of 3Com Ventures. Ms. Roberts
     disclaims beneficial ownership of shares held by 3Com Corp.

 (9) Includes 5,151,948 shares owned by Telcom-ATI Investors and entities it
     controls, and an additional 1,875,000 shares which Telcom-ATI Investors has
     the right to acquire over which Dr. Singh exercises voting and investment
     control by virtue of his position as chairman and chief executive officer
     of Telcom-ATI Investors.

(10) Includes vested options to purchase 11,250 shares of common stock. The
     amount shown excludes approximately 15,572 shares in which Mr. Stamas has
     an indirect interest as a result of his non-voting limited liability
     company membership interest in Telcom-ATI Investors and excludes the
     indirect interest Mr. Stamas has in 5,753 shares Telcom-ATI Investors has
     the right to acquire. Mr. Stamas also disclaims beneficial ownership of the
     1,995,325 shares beneficially owned by Pyramid Ventures, Inc., an affiliate
     of Deutsche Banc Alex. Brown.

(11) Mr. Vasan is a partner with Mayfield Fund. Mr. Vasan disclaims beneficial
     ownership of shares held by Mayfield Fund except to the extent of any
     pecuniary interest.

(12) Includes vested options to purchase 37,500 shares of common stock. Also
     includes 5,000 shares owned by the Carol and Tom Wheeler Foundation of
     which Mr. Wheeler is the trustee.

(13) Includes all the shares and options identified above and options for 20,833
     shares and 62,500 shares issuable upon exercise of options exercisable by
     April 30, 2000.

(14) Includes vested warrants to purchase 143,665 shares of common stock.

(15) Pyramid Ventures, Inc. is an indirect wholly-owned subsidiary of
     DeutscheBank AG.

(16) Reuters MarketClip Holdings Sarl is an indirect wholly-owned subsidiary of
     Reuters Group PLC.

(17) Includes an option to acquire 1,875,000 shares of common stock from NexGen
     at a price of $1.92 per share.

                                       74
<PAGE>   226

                              DESCRIPTION OF NOTES

     The notes will be issued under the Indenture (the "Indenture") between
Aether Systems, Inc. and                , as trustee (the "Trustee"). We have
filed the form of the Indenture as an exhibit to the registration statement. A
copy of the form of Indenture also will be made available to prospective
investors in the notes upon request to us and will be available for inspection
during normal business hours at the corporate trust office of the Trustee.

     We have described material provisions of the Indenture below. This summary
is not complete. We urge you to read the Indenture because it defines your
rights as a holder of the notes. Terms not defined in this description have the
meanings given them in the Indenture. In this section, "Aether," "we" and "us"
each refers only to Aether Systems, Inc. and not to any of its subsidiaries.

GENERAL

     The notes will be unsecured, subordinated obligations of Aether in an
aggregate principal amount of $200,000,000 (plus an aggregate principal amount
of $30,000,000 if the underwriters' over-allotment option is exercised in full),
and will mature on                , 2005. The principal amount of each note is
$1,000 and will be payable at the office of the Paying Agent, which initially
will be the Trustee, or an office or agency maintained by us for that purpose in
the Borough of Manhattan, City of New York.

     The notes will bear interest at the rate of      % per annum on the
principal amount from the date of issuance of the notes, or from the most recent
date on which interest has been paid or provided for until the notes are paid in
full or funds are made available for payment in full of the notes in accordance
with the Indenture. Interest will be payable at the date of maturity (or earlier
purchase, redemption or, in some circumstances, conversion) and semiannually on
               and                of each year (each an "Interest Payment
Date"), commencing on                , 2000, to holders of record at the close
of business on the                and                (whether or not a business
day) immediately preceding each Interest Payment Date (each a "Regular Record
Date"). Each payment of interest on the notes will include interest accrued
through the day before the applicable Interest Payment Date or the date of
maturity (or earlier purchase, redemption or, in some circumstances,
conversion), as the case may be. Any payment of principal and cash interest
required to be made on any day that is not a business day will be made on the
next succeeding business day. Interest will be computed on the basis of a
360-day year composed of twelve 30-day months. We currently expect to fund
interest payments through proceeds from this offering and the concurrent
offering of shares of our common stock. We cannot assure you that these
offerings will be accomplished on terms advantageous to us, or at all, or that
alternative sources of financing will be available to fund the interest
payments.

     In the event of the maturity, conversion, purchase by us at the option of a
holder or redemption of a note, interest will cease to accrue on that note,
under the terms and subject to the conditions of the Indenture. We may not
reissue a note that has matured or been converted, redeemed or otherwise
canceled, except for registration of transfer, exchange or replacement of that
note.

     You may present the notes for conversion at the office of the Conversion
Agent and for exchange or registration of transfer at the office of the
Registrar. Each of these agents will initially be the Trustee.

     The Indenture does not contain any financial covenants or restrictions on
the payment of dividends, the incurrence of Senior Indebtedness (defined below)
or the issuance or repurchase of securities by us. The Indenture contains no
covenants or other provisions to protect holders of the notes in the event of a
highly leveraged transaction or a change in control, except to the extent
described below under "-- Change in Control Permits Purchase of Notes at the
Option of the Holder."

SUBORDINATION

     The notes will be our unsecured obligations and will be subordinated in
right of payment, as provided in the Indenture, to the prior payment in full in
cash or other payment satisfactory to holders of Senior Indebtedness, of all our
existing and future Senior Indebtedness.
                                       75
<PAGE>   227

     At February 15, 2000, we had approximately $19.0 million of senior
indebtedness outstanding which we incurred in connection with our acquisition of
LocusOne. The notes will also be subordinate to approximately $360,000 of senior
indebtedness which will be incurred by one of our subsidiaries in connection
with our acquisition of Riverbed. The Indenture does not restrict the incurrence
by us or our subsidiaries of indebtedness or other obligations.

     The term "Senior Indebtedness" means the principal, premium, if any,
interest (including all interest accruing subsequent to the commencement of any
bankruptcy or similar proceeding, whether or not a claim for post-petition
interest is allowable as a claim in any such proceeding) and all other amounts
owed in respect of all our Indebtedness (defined below), whether outstanding on
the date of the Indenture or thereafter created, incurred, assumed, guaranteed
or in effect guaranteed by us, including all deferrals, renewals, extensions,
refinancings, replacements, restatements or refundings of, or amendments,
modifications or supplements to, the foregoing, except for:

     - any such Indebtedness the terms of which expressly provide that such
       Indebtedness shall not be senior in right of payment to the notes

     - any such Indebtedness that is by its terms subordinated to or pari passu
       with the notes, and

     - any Indebtedness between or among us or any of our subsidiaries, a
       majority of the voting stock of which we directly or indirectly own, or
       our affiliates, including all other debt securities and guarantees in
       respect of those debt securities issued to any trust, or trustees of any
       trust, partnership or other entity affiliated with us that is, directly
       or indirectly, a financing vehicle used by us in connection with the
       issuance by that financing vehicle of preferred securities or other
       securities that rank pari passu with, or junior to, the notes.

     The term "Indebtedness" means, with respect to any person:

     - all indebtedness, obligations and other liabilities, contingent or
       otherwise, of that person for borrowed money (including obligations of
       that person in respect of overdrafts, foreign exchange contracts,
       currency exchange or similar agreements, interest rate protection,
       hedging or similar agreements, and any loans or advances from banks,
       whether or not evidenced by notes or similar instruments) or evidenced by
       bonds, debentures, notes or similar instruments (whether or not the
       recourse of the lender is to the whole of the assets of that person or to
       only a portion thereof), other than any account payable or other accrued
       current liability or obligation, in each case incurred in the ordinary
       course of business in connection with the obtaining of materials or
       services

     - all reimbursement obligations and other liabilities, contingent or
       otherwise, of that person with respect to letters of credit, bank
       guarantees, bankers' acceptances, security purchase facilities or similar
       credit transactions

     - all obligations and liabilities, contingent or otherwise, in respect of
       deferred and unpaid balances on any purchase price of any property

     - all obligations and liabilities, contingent or otherwise, in respect of
       leases of that person required, in conformity with generally accepted
       accounting principles, to be accounted for as capitalized lease
       obligations on the balance sheet of that person and all obligations and
       other liabilities, contingent or otherwise, under any lease or related
       document, including, without limitation, the balance deferred and unpaid
       on any purchase price of any property and a purchase agreement, in
       connection with the lease of real property which provides that that
       person is contractually obligated to purchase or cause a third party to
       purchase the leased property and thereby guarantee a minimum residual
       value of the leased property to the lessor and the obligations of that
       person under that lease or related document to purchase or to cause a
       third party to purchase that leased property

                                       76
<PAGE>   228

     - all obligations of that person, contingent or otherwise, with respect to
       an interest rate or other swap, cap or collar agreement or other similar
       instrument or agreement or foreign currency hedge, exchange, purchase or
       similar instrument or agreement

     - all direct or indirect guarantees or similar agreements by that person in
       respect of, and obligations or liabilities, contingent or otherwise, of
       that person to purchase or otherwise acquire or otherwise assure a
       creditor against loss in respect of indebtedness, obligations or
       liabilities of another person of the kind described in the above clauses

     - any indebtedness, or other obligations described in the above clauses
       secured by any mortgage, pledge, lien or other encumbrance existing on
       property which is owned or held by that person, regardless of whether the
       indebtedness or other obligation secured thereby shall have been assumed
       by that person, and

     - any and all deferrals, renewals, extensions, refinancings, replacements,
       restatements and refundings of, or amendments, modifications or
       supplements to, or any indebtedness or obligation issued in exchange for,
       any indebtedness, obligation or liability of the kind described in the
       above clauses.

     Any Senior Indebtedness will continue to be Senior Indebtedness and will be
entitled to the benefits of the subordination provisions irrespective of any
amendment, modification or waiver of any of its terms.

     By reason of the application of the subordination provisions, in the event
of dissolution, insolvency, bankruptcy or other similar proceedings, upon any
distribution of our assets:

     - the holders of the notes are required to pay over their share of that
       distribution to the trustee in bankruptcy, receiver or other person
       distributing our assets for application to the payment of all Senior
       Indebtedness remaining unpaid, to the extent necessary to pay all holders
       of Senior Indebtedness in full in cash or other payment satisfactory to
       the holders of Senior Indebtedness, and

     - unsecured creditors of ours who are not holders of notes or holders of
       Senior Indebtedness of ours may recover less, ratably, than holders of
       Senior Indebtedness of ours, and may recover more, ratably, than the
       holders of notes.

     In addition, we may not pay the principal amount, the Change in Control
Purchase Price (defined below), any redemption amounts or interest with respect
to any notes, and we may not acquire any notes for cash or property, except as
provided in the Indenture, if:

     (1) any payment default on any Senior Indebtedness has occurred and is
         continuing beyond any applicable grace period or

     (2) any default, other than a payment default, with respect to Senior
         Indebtedness occurs and is continuing that permits the acceleration of
         the maturity of that Senior Indebtedness and that default is either the
         subject of judicial proceedings or we receive a written notice of that
         default (a "Senior Indebtedness Default Notice").

     Notwithstanding the foregoing, payments with respect to the notes may
resume and we may acquire notes for cash when:

     (a) the default with respect to the Senior Indebtedness is cured or waived
         or ceases to exist or

     (b) in the case of a default described in (2) above, 179 or more days pass
         after notice of the default is received by us, provided that the terms
         of the Indenture otherwise permit the payment or acquisition of the
         notes at that time.

     If we receive a Senior Indebtedness Default Notice, then a similar notice
received within nine months after receiving that Senior Indebtedness Default
Notice relating to the same default on the same issue of Senior Indebtedness
will not be effective to prevent the payment or acquisition of the notes as
provided

                                       77
<PAGE>   229

above. In addition, no payment may be made on the notes if any notes are
declared due and payable prior to their Stated Maturity by reason of the
occurrence of an Event of Default until the earlier of:

     - 120 days after the date of acceleration of the maturity of that Senior
       Indebtedness or

     - the payment in full of all Senior Indebtedness

but only if payment on the notes is then otherwise permitted under the terms of
the Indenture.

     Upon any payment or distribution of our assets to creditors upon any
dissolution, winding up, liquidation or reorganization of us, whether voluntary
or involuntary, or in bankruptcy, insolvency, receivership or other similar
proceedings, the holders of all the Senior Indebtedness will first be entitled
to receive payment in full, in cash or other payment satisfactory to the holders
of Senior Indebtedness, of all amounts due or to become due on that Senior
Indebtedness, or payment of those amounts must have been provided for, before
the holders of the notes will be entitled to receive any payment or distribution
with respect to any notes.

     The notes are effectively subordinated to all existing and future
liabilities of our subsidiaries. Any right of ours to receive assets of any of
our subsidiaries upon their liquidation or reorganization, and the consequent
right of the holders of the notes to participate in those assets, will be
subject to the claims of that subsidiary's creditors, including trade creditors,
except to the extent that we ourselves are recognized as a creditor of that
subsidiary, in which case our claims would still be subordinate to any security
interests in the assets of that subsidiary and any indebtedness of that
subsidiary senior to that held by us.

CONVERSION RIGHTS

     A holder of a note is entitled to convert it into shares of common stock at
any time on or before maturity, provided, that if a note is called for
redemption, the holder is entitled to convert it at any time before the close of
business on the redemption date. A note in respect of which a holder has
delivered a Change in Control Purchase Notice (defined below) exercising that
holder's option to require us to purchase that holder's note, may be converted
only if the Change in Control Purchase Notice is withdrawn by a written notice
of withdrawal delivered by the holder to the Paying Agent prior to the close of
business on the Change in Control Purchase Date, in accordance with the terms of
the Indenture.

     The initial conversion price for the notes is $     per share of common
stock, which is equal to a Conversion Rate of                shares per $1,000
principal amount of notes. The Conversion Rate is subject to adjustment upon the
occurrence of some events described below. A holder otherwise entitled to a
fractional share of common stock will receive cash in an amount equal to the
market value of that fractional share based on the closing sale price on the
trading day immediately preceding the Conversion Date. A holder may convert a
portion of that holder's notes so long as that portion is $1,000 principal
amount or an integral multiple of $1,000.

     To convert a note, a holder must:

     - complete and manually sign the conversion notice on the back of the note,
       or complete and manually sign a facsimile of the note, and deliver the
       conversion notice to the Conversion Agent, initially the Trustee, at the
       office maintained by the Conversion Agent for that purpose

     - surrender the note to the Conversion Agent

     - if required, furnish appropriate endorsements and transfer documents, and

     - if required, pay all transfer or similar taxes.

     Under the Indenture, the date on which all of these requirements have been
satisfied is the Conversion Date.

     Upon conversion of a note, a holder will not receive, except as provided
below, any cash payment representing accrued interest on the note. Our delivery
to the holder of the fixed number of shares of common stock into which the note
is convertible, together with any cash payment to be made instead of
                                       78
<PAGE>   230

any fractional shares, will satisfy our obligation to pay the principal amount
of the note, and the accrued and unpaid interest to the Conversion Date. Thus,
the accrued but unpaid interest to the Conversion Date will be deemed to be paid
in full rather than cancelled, extinguished or forfeited. Notwithstanding the
foregoing, accrued but unpaid cash interest will be payable upon any conversion
of notes at the option of the holder made concurrently with or after
acceleration of the notes following an Event of Default described under
"-- Events of Default" below. Notes surrendered for conversion during the period
from the close of business on any Regular Record Date next preceding any
Interest Payment Date to the opening of business on that Interest Payment Date,
except notes to be redeemed on a date within that period, must be accompanied by
payment of an amount equal to the interest on the surrendered notes that the
registered holder is to receive. Except where notes surrendered for conversion
must be accompanied by payment as described above, no interest on converted
notes will be payable by us on any Interest Payment Date subsequent to the date
of conversion. The Conversion Rate will not be adjusted at any time during the
term of the notes for accrued interest.

     A certificate for the number of full shares of common stock into which any
note is converted, and any cash payment to be made instead of any fractional
shares, will be delivered as soon as practicable, but in any event no later than
the seventh business day following the Conversion Date. For a summary of the
U.S. federal income tax treatment of a holder receiving common stock upon
conversion, see "U.S. Federal Income Tax Considerations to U.S.
Holders -- Conversion of Notes" on page 94.

     The Conversion Rate is subject to adjustment in some events, including:

     - the issuance of shares of common stock as a dividend or a distribution
       with respect to common stock

     - subdivisions and combinations of common stock

     - the issuance to all holders of common stock of rights or warrants
       entitling them, for a period not exceeding 45 days, to subscribe for
       shares of our common stock at less than the current market price as
       defined in the Indenture

     - the distribution to holders of common stock of evidences of our
       indebtedness, securities or capital stock, cash or assets, including
       securities, but excluding common stock distributions covered above, those
       rights, warrants, dividends and distributions referred to above,
       dividends and distributions paid exclusively in cash and distributions
       upon mergers or consolidations resulting in a reclassification,
       conversion, exchange or cancellation of common stock covered in a
       Transaction adjustment described below

     - the payment of dividends and other distributions on common stock paid
       exclusively in cash, if the aggregate amount of these dividends and other
       distributions, when taken together with:

        - other all-cash distributions made within the preceding 12 months not
          triggering a Conversion Rate adjustment and

        - any cash and the fair market value, as of the expiration of the tender
          or exchange offer referred to below, of consideration payable in
          respect of any tender or exchange offer by us or one of our
          subsidiaries for the common stock concluded within the preceding 12
          months not triggering a Conversion Rate adjustment,

       exceeds 10% of our aggregate market capitalization on the date of the
       payment of those dividends and other distributions. The aggregate market
       capitalization is the product of the current market price of common stock
       as of the trading day immediately preceding the date of declaration of
       the applicable dividend multiplied by the number of shares of common
       stock then outstanding and

     - payment to holders of common stock in respect of a tender or exchange
       offer, other than an odd-lot offer, by us or one of our subsidiaries for
       common stock as of the trading day next succeeding the last date tenders
       or exchanges may be made pursuant to a tender or exchange offer by us or
       one of our subsidiaries, which involves an aggregate consideration that,
       together with:

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        - any cash and the fair market value of other consideration payable in
          respect of any tender or exchange offer by us or one of our
          subsidiaries for the common stock concluded within the preceding 12
          months not triggering a Conversion Rate adjustment and

        - the aggregate amount of any all-cash distributions to all holders of
          our common stock made within the preceding 12 months not triggering a
          Conversion Rate adjustment,

       exceeds 10% of our aggregate market capitalization.

     Notwithstanding the foregoing, adjustment is not necessary if holders may
participate in the transactions otherwise giving rise to an adjustment on a
basis and with notice that our Board of Directors determines to be fair and
appropriate, or in some other cases specified in the Indenture. No adjustment in
the Conversion Rate will be required unless it would require a change of at
least 1% in the Conversion Rate then in effect; provided that any adjustment
that would otherwise be required to be made shall be carried forward and taken
into account in any subsequent adjustment. The Indenture permits us to increase
the Conversion Rate from time to time.

     In the event that we become a party to any transaction, including, and with
some exceptions:

     - any recapitalization or reclassification of the common stock

     - any consolidation of us with, or merger of us into, any other Person, or
       any merger of another Person into us

     - any sale, transfer or lease of all or substantially all of our assets or

     - any compulsory share exchange

pursuant to which the common stock is converted into the right to receive other
securities, cash or other property (each of the above being referred to as a
"Transaction"), then the holders of notes then outstanding will have the right
to convert the notes only into the kind and amount of securities, cash or other
property receivable upon the consummation of that Transaction by a holder of the
number of shares of common stock issuable upon conversion of those notes
immediately prior to that Transaction.

     In the case of a Transaction, each note will become convertible into the
securities, cash or property receivable by a holder of the number of shares of
the common stock into which the note was convertible immediately prior to that
Transaction. This change could substantially lessen or eliminate the value of
the conversion privilege associated with the notes in the future. For example,
if we were acquired in a cash merger, each note would become convertible solely
into cash and would no longer be convertible into securities whose value would
vary depending on our future prospects and other factors.

     In the event of a taxable distribution to holders of common stock which
results in an adjustment of the Conversion Rate, or in which holders otherwise
participate, or in the event the Conversion Rate is increased at our discretion,
the holders of the notes may, in some circumstances, be deemed to have received
a distribution subject to United States federal income tax as a dividend.
Moreover, in some other circumstances, the absence of an adjustment to the
Conversion Rate may result in a taxable dividend to holders of common stock. See
"U.S. Federal Income Tax Considerations to U.S. Holders -- Ownership and
Disposition of Common Stock -- Adjustment of Conversion Rate" on page 96.

PROVISIONAL REDEMPTION

     We may redeem the notes, in whole or in part, at any time prior to
                 , 2003, at a redemption price equal to $1,000 per $1,000
principal amount of notes to be redeemed plus accrued and unpaid interest, if
any, to the provisional redemption date if the closing price of our common stock
has exceeded 150% of the conversion price then in effect for at least 20 trading
days within a period of 30 consecutive trading days ending on the trading day
prior to the date of mailing of the provisional redemption notice (which date
shall be no more than 60 nor less than 30 days prior to the provisional
redemption date).

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     Upon any provisional redemption, we will make an additional payment in cash
with respect to the notes called for redemption to holders on the notice date in
an amount equal to $     per $1,000 principal amount of notes, less the amount
of any interest actually paid on the notes prior to the notice date. WE WILL BE
OBLIGATED TO MAKE THIS ADDITIONAL PAYMENT ON ALL NOTES CALLED FOR PROVISIONAL
REDEMPTION, INCLUDING ANY NOTES CONVERTED AFTER THE NOTICE DATE AND BEFORE THE
PROVISIONAL REDEMPTION DATE.

REDEMPTION OF NOTES AT OUR OPTION

     There is no sinking fund for the notes. On and after                  ,
2003, we will be entitled to redeem the notes for cash as a whole at any time,
or from time to time in part, upon not less than 30 days' nor more than 60 days'
notice of redemption given by mail to holders of notes, unless a shorter notice
is satisfactory to the Trustee, at the redemption prices set out below plus
accrued cash interest to the redemption date. Any redemption of the notes must
be in integral multiples of $1,000 principal amount.

     The table below shows redemption prices of a note per $1,000 principal
amount if redeemed during the twelve-month periods described below.

<TABLE>
<CAPTION>
PERIOD                                                        REDEMPTION PRICE
- ------                                                        ----------------
<S>                                                           <C>
            , 2003 through             , 2004...............          %
Thereafter..................................................          %
</TABLE>

     If fewer than all of the notes are to be redeemed, the Trustee will select
the notes to be redeemed in principal amounts at maturity of $1,000 or integral
multiples of $1,000 by lot, pro rata or by another method the Trustee considers
fair and appropriate. If a portion of a holder's notes is selected for partial
redemption and that holder converts a portion of those notes prior to the
redemption, the converted portion will be deemed, solely for purposes of
determining the aggregate principal amount of the notes to be redeemed by us, to
be of the portion selected for redemption.

CHANGE IN CONTROL PERMITS PURCHASE OF NOTES AT THE OPTION OF THE HOLDER

     In the event of any Change in Control (defined below) of Aether, each
holder of notes will have the right, at the holder's option, subject to the
terms and conditions of the Indenture, to require us to purchase all or any
part, provided that the principal amount must be $1,000 or an integral multiple
of $1,000, of the holder's notes. Each holder of notes will have the right to
require us to make that purchase on the date that is 45 business days after the
occurrence of the Change in Control (the "Change in Control Purchase Date") at a
price equal to 100% of the principal amount of that holder's notes plus accrued
interest to the Change in Control Purchase Date (the "Change in Control Purchase
Price").

     We may, at our option, instead of paying the Change in Control Purchase
Price in cash, pay the Change in Control Purchase Price in our common stock
valued at 95% of the average of the closing sales prices of our common stock for
the five trading days immediately preceding and including the third day prior to
the Change in Control Date. We cannot pay the Change in Control Purchase Price
in common stock unless we satisfy the conditions as described in the Indenture.

     Within 15 business days after the Change in Control, we will mail to the
Trustee and to each holder, and to beneficial owners as required by applicable
law, a notice regarding the Change in Control, which will state, among other
things:

     - the date of the Change in Control and, briefly, the events causing the
       Change in Control

     - the date by which the Change in Control Purchase Notice (defined below)
       must be given

     - the Change in Control Purchase Date

     - the Change in Control Purchase Price and method of payment

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<PAGE>   233

     - the name and address of the Paying Agent and the Conversion Agent

     - the Conversion Rate and any adjustments to the Conversion Rate

     - the procedures that holders must follow to exercise these rights

     - the procedures for withdrawing a Change in Control Purchase Notice

     - that holders who want to convert notes must satisfy the requirements
       provided in the notes, and

     - briefly, the conversion rights of holders of notes.

     We will cause a copy of the notice regarding the Change in Control to be
published in The Wall Street Journal or another daily newspaper of national
circulation.

     To exercise the purchase right, the holder must deliver written notice of
the exercise of the purchase right (a "Change in Control Purchase Notice") to
the Paying Agent or an office or agency maintained by us for that purpose in the
Borough of Manhattan, The City of New York, prior to the close of business, on
the Change in Control Purchase Date. Any Change in Control Purchase Notice must
state:

     - the name of the holder

     - the certificate numbers of the notes to be delivered by the holder of
       those notes for purchase by us

     - the portion of the principal amount of notes to be purchased, which
       portion must be $1,000 or an integral multiple of $1,000, and

     - that the notes are to be purchased by us pursuant to the applicable
       provisions of the notes.

     A holder may withdraw any Change in Control Purchase Notice by a written
notice of withdrawal delivered to the Paying Agent prior to the close of
business on the Change in Control Purchase Date. The notice of withdrawal must
state the principal amount and the certificate numbers of the notes as to which
the withdrawal notice relates and the principal amount, if any, which remains
subject to a Change in Control Purchase Notice.

     Payment of the Change in Control Purchase Price for a note for which a
Change in Control Purchase Notice has been delivered and not withdrawn is
conditioned upon delivery of the note, together with necessary endorsements, to
the Paying Agent or an office or agency maintained by us for that purpose in the
Borough of Manhattan, The City of New York, at any time, whether prior to, on or
after the Change in Control Purchase Date, after the delivery of the Change in
Control Purchase Notice. Payment of the Change in Control Purchase Price for the
note will be made promptly following the later of the business day following the
Change in Control Purchase Date and the time of delivery of the note. If the
Paying Agent holds, in accordance with the terms of the Indenture, money
sufficient to pay the Change in Control Purchase Price of that note on the
business day following the Change in Control Purchase Date, then, immediately
after the Change in Control Purchase Date, that note will cease to be
outstanding and interest on that note will cease to accrue and will be deemed
paid, whether or not that note is delivered to the Paying Agent, and all other
rights of the holder will terminate, other than the right to receive the Change
in Control Purchase Price upon delivery of that note.

     Under the Indenture, a "Change in Control" of Aether is deemed to have
occurred upon the occurrence of any of the following events:

     - any "person" or "group" (as such terms are used in Sections 13(d) and
       14(d) of the Exchange Act), acquires the beneficial ownership (as defined
       in Rules 13d-3 and 13d-5 under the Exchange Act, except that a Person
       shall be deemed to have "beneficial ownership" of all securities that
       such Person has the right to acquire, whether such right is exercisable
       immediately or only after the passage of time), directly or indirectly,
       through a purchase, merger or other acquisition transaction, of more than
       50% of our total outstanding voting stock, other than an acquisition by
       us, any of our subsidiaries or any of our employee benefit plans.

                                       82
<PAGE>   234

     - we consolidate with, or merge with or into another Person or convey,
       transfer, lease or otherwise dispose of all or substantially all of our
       assets to any Person, or any Person consolidates with or merges with or
       into us, in any such event pursuant to a transaction in which our
       outstanding voting stock is converted into or exchanged for cash,
       securities or other property, other than where:

        - our voting stock is not converted or exchanged at all, except to the
          extent necessary to reflect a change in our jurisdiction of
          incorporation, or is converted into or exchanged for voting stock,
          other than Redeemable Capital Stock (defined below), of the surviving
          or transferee corporation and

        - immediately after such transaction, no "person" or "group" (as such
          terms are used in Sections 13(d) and 14(d) of the Exchange Act) is the
          "beneficial owner" (as defined in Rules 13d-3 and 13d-5 under the
          Exchange Act, except that a Person will be deemed to have "beneficial
          ownership" of all securities that such Person has the right to
          acquire, whether such right is exercisable immediately or only after
          the passage of time), directly or indirectly, of more than 50% of the
          total outstanding voting stock of the surviving or transferee
          corporation

     - during any consecutive two-year period, individuals who at the beginning
       of that two-year period constituted our Board of Directors (together with
       any new directors whose election to such Board of Directors, or whose
       nomination for election by our stockholders, was approved by a vote of a
       majority of the directors then still in office who were either directors
       at the beginning of such period or whose election or nomination for
       election was previously so approved) cease for any reason to constitute a
       majority of our Board of Directors then in office or

     - our stockholders pass a special resolution approving a plan of
       liquidation or dissolution.

     "Redeemable Capital Stock" means any class or series of capital stock that,
either by its terms, by the terms of any security into which it is convertible
or exchangeable or by contract or otherwise, is, or upon the happening of an
event or passage of time would be, required to be redeemed prior to the final
stated maturity of the notes or is redeemable at the option of the holder of the
notes at any time prior to such final stated maturity, or is convertible into or
exchangeable for debt securities at any time prior to such final stated
maturity. Redeemable Capital Stock will not include any common stock the holder
of which has a right to put to us upon some terminations of employment.

     The Indenture does not permit the Board of Directors to waive our
obligation to purchase notes at the option of a holder in the event of a Change
in Control of Aether.

     We will comply with the provisions of Rule 13e-4, Rule 14e-1 and any other
tender offer rules under the Exchange Act which may then be applicable, and will
file Schedule 13E-4 or any other schedule required under the Exchange Act in
connection with any offer by us to purchase notes at the option of the holders
of notes upon a Change in Control. In some circumstances, the Change in Control
purchase feature of the notes may make more difficult or discourage a takeover
of us and, thus, the removal of incumbent management. The Change in Control
purchase feature, however, is not the result of management's knowledge of any
specific effort to accumulate shares of common stock or to obtain control of us
by means of a merger, tender offer, solicitation or otherwise, or part of a plan
by management to adopt a series of anti-takeover provisions. Instead, the Change
in Control purchase feature is the result of negotiations between us and the
underwriters.

     If a Change in Control were to occur, we cannot assure you that we would
have funds sufficient to pay the Change in Control Purchase Price for all of the
notes that might be delivered by holders seeking to exercise the purchase right,
because we or our subsidiaries might also be required to prepay some
indebtedness or obligations having financial covenants with change of control
provisions in favor of the holders of that indebtedness or those obligations. In
addition, our other indebtedness may have cross-default provisions that could be
triggered by a default under the Change in Control provisions thereby possibly
accelerating the maturity of that other indebtedness. In that case, the holders
of the notes would be subordinated to the prior claims of the holders of other
indebtedness having cross-default provisions. In

                                       83
<PAGE>   235

addition, our ability to purchase the notes with cash may be limited by the
terms of our then-existing borrowing agreements. No notes may be purchased
pursuant to the provisions described above if there has occurred and is
continuing an Event of Default described under "-- Events of Default" below
(other than a default in the payment of the Change in Control Purchase Price
with respect to those notes).

CONSOLIDATION, MERGER AND SALE OF ASSETS

     We, without the consent of any holders of outstanding notes, are entitled
to consolidate with or merge into or transfer or lease our assets substantially
as an entirety to, any individual, corporation, partnership, limited liability
company, joint venture, association, joint-stock company, trust, unincorporated
organization or government or any agency or political subdivision thereof (each
a "Person"), and any Person is entitled to consolidate with or merge into, or
transfer or lease its assets substantially as an entirety to us, provided that:

     - the Person, if other than us, formed by a consolidation or into which we
       are merged or the Person which acquires or leases our assets
       substantially as an entirety is a corporation, partnership, limited
       liability company or trust organized and existing under the laws of any
       United States jurisdiction and expressly assumes our obligations on the
       notes and under the Indenture

     - immediately after giving effect to the consolidation, merger, transfer or
       lease, no Event of Default (defined below), and no event which, after
       notice or lapse of time or both, would become an Event of Default,
       happened and is continuing, and

     - an officer's certificate and an opinion of counsel, each stating that the
       consolidation, merger, transfer or lease complies with the provisions of
       the Indenture, have been delivered by us to the Trustee.

EVENTS OF DEFAULT

     The Indenture provides that, if an Event of Default specified in the
Indenture occurs and is continuing, either the Trustee or the holders of not
less than 25% in aggregate principal amount of the notes then outstanding may
declare the principal amount of, and accrued interest to the date of that
declaration, on all the notes to be immediately due and payable. In the case of
some events of bankruptcy or insolvency, the principal amount of, and accrued
interest on all the notes to the date of the occurrence of that event, will
automatically become and be immediately due and payable. Upon any acceleration
of the payment of principal amount and accrued interest, the subordination
provisions of the Indenture will preclude any payment being made to holders of
notes until the earlier of:

     - 120 days or more after the date of that acceleration and

     - the payment in full of all Senior Indebtedness,

but only if such payment is then otherwise permitted under the terms of the
Indenture. See "-- Subordination."

     Under some circumstances, the holders of a majority in aggregate principal
amount of the outstanding notes may rescind any acceleration with respect to the
notes and its consequences.

     Interest will accrue and be payable on demand upon a default in:

     - the payment of:

        - principal and interest when due

        - redemption amounts or

        - Change in Control Purchase Price

     - the delivery of shares of common stock to be delivered on conversion of
       notes or

     - the payment of cash in lieu of fractional shares to be paid on conversion
       of notes
                                       84
<PAGE>   236

in each case to the extent that the payment of interest which is due, is legally
enforceable.

     Under the Indenture, Events of Default include:

     - default in payment of the principal amount, interest when due (if that
       default in payment of interest continues for 30 days), any redemption
       amounts or the Change in Control Purchase Price with respect to any note,
       when that principal amount, interest, redemption amount or Change in
       Control Purchase Price becomes due and payable (whether or not that
       payment is prohibited by the provisions of the Indenture)

     - failure by us to deliver shares of common stock, together with cash
       instead of fractional shares, when those shares of common stock, or cash
       instead of fractional shares, are required to be delivered following
       conversion of a note, and that default continues for 10 days

     - failure by us to comply with any of our other agreements in the notes or
       the Indenture upon the receipt by us of notice of that default from the
       Trustee or from holders of not less than 25% in aggregate principal
       amount of the notes then outstanding and our failure to cure that default
       within 60 days after our receipt of that notice

     - default under any bond, note or other evidence of indebtedness for money
       borrowed by us having an aggregate outstanding principal amount in excess
       of $10 million, which default shall have resulted in that indebtedness
       being accelerated, without that indebtedness being discharged or that
       acceleration having been rescinded or annulled within 30 days after our
       receipt of the notice of default from the Trustee or receipt by us and
       the Trustee of the notice of default from the holders of not less than
       25% in aggregate principal amount of the notes then outstanding, unless
       that default has been cured or waived or

     - some events of bankruptcy or insolvency.

     The Trustee will, within 90 days after the occurrence of any default, mail
to all holders of the notes notice of all defaults of which the Trustee is
aware, unless those defaults have been cured or waived before the giving of that
notice. The Trustee may withhold notice as to any default other than a payment
default, if it determines in good faith that withholding the notice is in the
interests of the holders. The term default for the purpose of this provision
means any event that is, or after notice or lapse of time or both would become,
an Event of Default with respect to the notes.

     The holders of a majority in aggregate principal amount of the outstanding
notes may direct the time, method and place of conducting any proceeding for any
remedy available to the Trustee or exercising any trust or power conferred on
the Trustee, provided that the direction must not be in conflict with any law or
the Indenture and the direction is subject to some other limitations. The
Trustee may refuse to perform any duty or exercise any right or power or extend
or risk its own funds or otherwise incur any financial liability unless it
receives indemnity satisfactory to it against any loss, liability or expense. No
holder of any note will have any right to pursue any remedy with respect to the
Indenture or the notes, unless:

     - that holder has previously given the Trustee written notice of a
       continuing Event of Default

     - the holders of at least 25% in aggregate principal amount of the
       outstanding notes have made a written request to the Trustee to pursue
       the relevant remedy

     - the holder giving that written notice has, or the holders making that
       written request have, offered to the Trustee reasonable security or
       indemnity against any loss, liability or expense satisfactory to it

     - the Trustee has failed to comply with the request within 60 days after
       receipt of that notice, request and offer of security or indemnity, and

     - the holders of a majority in aggregate principal amount of the
       outstanding notes have not given the Trustee a direction inconsistent
       with that request within 60 days after receipt of that request.

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<PAGE>   237

     The right of any holder:

     - to receive payment of principal, any redemption amounts, the Change in
       Control Purchase Price or interest in respect of the notes held by that
       holder on or after the respective due dates expressed in the notes

     - to convert those notes or

     - to bring suit for the enforcement of any payment of principal, any
       redemption amounts, the Change in Control Purchase Price or interest in
       respect of those notes held by that holder on or after the respective due
       dates expressed in the notes, or the right to convert,

will not be impaired or adversely affected without that holder's consent.

     The holders of a majority in aggregate principal amount of notes at the
time outstanding may waive any existing default and its consequences except:

     - any default in any payment on the notes

     - any default with respect to the conversion rights of the notes or

     - any default in respect of the covenants or provisions in the Indenture
       which may not be modified without the consent of the holder of each note
       as described in "-- Modification, Waiver and Meetings" below.

     When a default is waived, it is deemed cured and will cease to exist, but
that waiver does not extend to any subsequent or other default or impair any
consequent right.

     We will be required to furnish to the Trustee annually a statement as to
any default by us in the performance and observance of our obligations under the
Indenture. In addition, we will be required to file with the Trustee written
notice of the occurrence of any default or Event of Default within five business
days of our becoming aware of the occurrence of any default or Event of Default.

MODIFICATION, WAIVER AND MEETINGS

     The Indenture or the notes may be modified or amended by us and the Trustee
with the consent of the holders of not less than a majority in aggregate
principal amount of the notes then outstanding. The Indenture or the notes may
not be modified or amended by us without the consent of each holder affected
thereby, to, among other things:

     - reduce the principal amount, Change in Control Purchase Price or any
       redemption amounts with respect to any note, or extend the stated
       maturity of any note or alter the manner of payment or rate of interest
       on any note or make any note payable in money or securities other than
       that stated in the note

     - make any reduction in the principal amount of notes whose holders must
       consent to an amendment or any waiver under the Indenture or modify the
       Indenture provisions relating to those amendments or waivers

     - make any change that adversely affects the right of a holder to convert
       any note

     - modify the provisions of the Indenture relating to the ranking of the
       notes in a manner adverse to the holders of the notes or

     - impair the right to institute suit for the enforcement of any payment
       with respect to, or conversion of, the notes.

     Without the consent of any holder of notes, we and the Trustee may amend
the Indenture to:

     - cure any ambiguity, defect or inconsistency

     - provide for the assumption by a successor of our obligations under the
       Indenture

                                       86
<PAGE>   238

     - provide for uncertificated notes in addition to certificated notes, as
       long as those uncertificated notes are in registered form for United
       States federal income tax purposes

     - make any change that does not adversely affect the rights of any holder
       of notes

     - make any change to comply with any requirement of the SEC in connection
       with the qualification of the Indenture under the Trust Indenture Act of
       1939, as amended

     - add to our covenants or our obligations under the Indenture for the
       protection of holders of the notes or

     - surrender any right, power or option conferred by the Indenture on us.

FORM, DENOMINATION, EXCHANGE, REGISTRATION, TRANSFER AND PAYMENT

     We expect to initially issue the notes in the form of one or more global
notes. The global notes will be deposited with, or on behalf of, The Depository
Trust Company ("DTC"), and registered in the name of DTC or its nominee. The
notes will be issued in denominations of $1,000 and $1,000 multiples.

     The principal, any premium and any interest on the notes will be payable,
without coupons, and the exchange of and the transfer of the notes will be
registrable, at our office or agency maintained for that purpose in the Borough
of Manhattan, City of New York and at any other office or agency maintained for
that purpose.

     Holders may present the notes for exchange, and for registration of
transfer, with the form of transfer endorsed on those notes, or with a
satisfactory written instrument of transfer, duly executed, at the office of the
appropriate securities registrar or at the office of any transfer agent
designated by us for that purpose, without service charge and upon payment of
any taxes and other governmental charges as described in the Indenture. We will
appoint the Trustee of the notes as securities registrar under the Indenture. We
may at any time rescind designation of any transfer agent or approve a change in
the location through which any transfer agent acts, provided that we maintain a
transfer agent in each place of payment for the notes. We may at any time
designate additional transfer agents for the notes.

     All moneys paid by us to a paying agent for the payment of principal, any
premium or any interest, on any note which remains unclaimed for two years after
the principal, premium or interest has become due and payable may be repaid to
us, and after the two-year period, the holder of that note may look only to us
for payment.

     In the event of any redemption, we will not be required to:

     - issue, register the transfer of or exchange notes during a period
       beginning at the opening of business 15 days before the day of the
       mailing of a notice of redemption of notes to be redeemed and ending at
       the close of business on the day of that mailing or

     - register the transfer of or exchange any note called for redemption,
       except, in the case of any notes being redeemed in part, any portion not
       being redeemed.

BOOK-ENTRY SYSTEM

     Upon the issuance of a global note, DTC will credit, on its book-entry
registration and transfer system, the respective principal amounts of the notes
represented by that global note to the accounts of institutions or persons,
commonly known as participants, that have accounts with DTC or its nominee. The
accounts to be credited will be designated by the underwriters, dealers or
agents. Ownership of beneficial interests in a global note will be limited to
participants or persons that may hold interests through participants. Ownership
of interests in a global note will be shown on, and the transfer of those
ownership interests will be effected only through, records maintained by DTC
(with respect to participants' interests) and the participants (with respect to
the owners of beneficial interests in that global note). The laws of some
jurisdictions may require that some purchasers of securities take physical
delivery of the securities in

                                       87
<PAGE>   239

definitive form. These limits and laws may impair the ability to transfer
beneficial interests in a global note.

     So long as DTC, or its nominee, is the registered holder and owner of the
global note, DTC or its nominee, as the case may be, will be considered the sole
owner and holder for all purposes of the notes and for all purposes under the
Indenture. Except as described below, owners of beneficial interests in a global
note will not be entitled to have the notes represented by that global note
registered in their names, will not receive or be entitled to receive physical
delivery of notes in definitive form and will not be considered to be the owners
or holders of any notes under the Indenture or that global note. Accordingly,
each person owning a beneficial interest in a global note must rely on the
procedures of DTC and, if that person is not a participant, on the procedures of
the participant through which that person owns its interest, to exercise any
rights of a holder of notes under the Indenture of that global note. We
understand that under existing industry practice, in the event we request any
action of holders of notes or if an owner of a beneficial interest in a global
note desires to take any action that DTC, as the holder of that global note is
entitled to take, DTC would authorize the participants to take that action, and
that the participants would authorize beneficial owners owning through them to
take those actions or would otherwise act upon the instructions of beneficial
owners owning through them.

     Payments of principal of and any premium and any interest on the notes
represented by a global note will be made to DTC or its nominee, as the case may
be, as the registered owner and holder of that global note, against surrender of
the notes at the principal corporate trust office of the Trustee. Interest
payments will be made at the principal corporate trust office of the Trustee or
by a check mailed to the holder at its registered address.

     We expect that DTC, upon receipt of any payment of principal, and any
premium and any interest, in respect of a global note, will immediately credit
the participants' accounts with payments in amounts proportionate to their
respective beneficial interests in the principal amount of that global note as
shown on the records of the DTC. We expect that payments by participants to
owners of beneficial interests in a global note held through those participants
will be governed by standing instructions and customary practices, as is now the
case with securities held for the accounts of customers in bearer form or
registered in "street name," and will be the responsibility of those
participants. We, our agent, the Trustee and its agent will not have any
responsibility or liability for any aspect of the records relating to, or
payments made on account of, beneficial ownership interests in a global note or
for maintaining, supervising or reviewing any records relating to those
beneficial ownership interests or for any other aspect of the relationship
between DTC and its participants or the relationship between those participants
and the owners of beneficial interests in that global note owning through those
participants.

     Unless and until it is exchanged in whole or in part for notes in
definitive form, a global note may not be transferred except as a whole by DTC
to a nominee of DTC or by a nominee of DTC to DTC or a successor to DTC selected
or approved by us or to a nominee of that successor to DTC.

     The notes represented by a global note will be exchangeable for notes in
definitive form of like tenor as that global note in denominations of $1,000 and
in any greater amount that is an integral multiple of $1,000 if:

     - DTC notifies us and the Trustee that it is unwilling or unable to
       continue as depositary for that global note or if at any time DTC ceases
       to be a clearing agency registered under the Exchange Act and a successor
       depositary is not appointed by us within 90 days

     - we, in our sole discretion, determine not to have all of the notes
       represented by a global note and notify the Trustee of that determination
       or

     - there is, or continues to be, an event of default or there is an event
       which, with the giving of notice or lapse of time, or both, would
       constitute an event of default with respect to the notes.

     Any note that is exchangeable pursuant to the preceding sentence is
exchangeable for notes registered in the names which DTC will instruct the
Trustee. It is expected that DTC's instructions may be based

                                       88
<PAGE>   240

upon directions received by DTC from its participants with respect to ownership
of beneficial interests in that global note. Subject to the foregoing, a global
note is not exchangeable except for a global note or global notes of the same
aggregate denominations to be registered in the name of DTC or its nominee.

NOTICES

     Except as otherwise provided in the Indenture, notices to holders of notes
will be given by mail to the addresses of holders of the notes as they appear in
the Security Register.

REPLACEMENT OF NOTES

     Any mutilated note will be replaced by us at the expense of the holder upon
surrender of that note to the Trustee. Notes that become destroyed, stolen or
lost will be replaced by us at the expense of the holder upon delivery to the
Trustee of notes or evidence of the destruction, loss or theft of the notes
satisfactory to us and the Trustee. In the case of a destroyed, lost or stolen
note, an indemnity satisfactory to the Trustee and us may be required at the
expense of the holder of that note before a replacement note will be issued.

GOVERNING LAW

     The Indenture and the notes will be governed by, and construed in
accordance with, the laws of the State of New York.

INFORMATION REGARDING THE TRUSTEE

                 is the Trustee, Securities Registrar, Paying Agent and
Conversion Agent under the Indenture.

                                       89
<PAGE>   241

                          DESCRIPTION OF CAPITAL STOCK

     Our authorized capital stock consists of 75,000,000 shares of common stock,
$.01 par value, and 1,000,000 shares of preferred stock, $.01 par value.

COMMON STOCK

     As of February 15, 2000 assuming the completion of the Riverbed
acquisition, there were 32,018,468 shares of common stock outstanding that were
held of record by approximately 19 recordholders. As of the same date, there
were options and warrants to purchase a total of 4,875,054 shares of common
stock assuming completion of the acquisition of Riverbed. As of February 15,
2000, assuming the completion of our Riverbed acquisition, there would be
34,509,687 shares of common stock outstanding (assuming no exercise of the
underwriters' over-allotment option) after giving effect to the sale of the
shares of common stock offered in the concurrent common stock offering. After
completion of this offering of convertible notes there will be convertible notes
outstanding that are convertible into an aggregate of      shares of common
stock.

     The holders of common stock are entitled to one vote per share on all
matters to be voted upon by the stockholders. Subject to preferences that may be
applicable to any outstanding preferred stock, the holders of common stock are
entitled to receive ratably any dividends that may be declared from time to time
by the board of directors out of funds legally available therefor. In the event
of a liquidation, dissolution or winding up of Aether, the holders of common
stock are entitled to share ratably in all assets remaining after payment of
liabilities, subject to prior rights of holders of preferred stock, if any, then
outstanding. The common stock has no preemptive or conversion rights or other
subscription rights. There are no redemption or sinking fund provisions
available to the common stock. All outstanding shares of common stock are fully
paid and non-assessable.

PREFERRED STOCK

     Aether is authorized to issue 1,000,000 shares of undesignated preferred
stock. The board of directors has the authority to issue the undesignated
preferred stock in one or more series and to determine the powers, preferences
and rights and the qualifications, limitations or restrictions granted to or
imposed upon any wholly unissued series of undesignated preferred stock and to
fix the number of shares constituting any series and the designation of a
series, without any further vote or action by the stockholders. The issuance of
preferred stock may have the effect of delaying, deferring or preventing a
change in control of Aether without further action by the stockholders and may
adversely affect the voting and other rights of the holders of common stock.
Furthermore, this preferred stock may have other rights, including economic
rights senior to the common stock, and, as a result, the issuance of preferred
stock could have a material adverse effect on the market value of the common
stock. At present, we have no plans to issue any shares of preferred stock.

STOCKHOLDER'S AGREEMENT

     NexGen, Telcom-ATI Investors, Reuters and 3Com entered into a stockholders
agreement which requires these parties to vote to elect to the board of
directors two persons named by each of NexGen and Telcom-ATI Investors, two
persons named jointly by NexGen and Telcom-ATI Investors and one person named by
each of Reuters and 3Com. We describe the terms of this agreement in further
detail in "Transactions Between Aether and its Officers, Directors or
Significant Stockholders" on page 69.

REGISTRATION RIGHTS OF STOCKHOLDERS

     We and NexGen, Telcom-ATI Investors, Reuters, 3Com, J. Carter Beese, Jr.
and Mark D. Ein entered into a registration rights agreement requiring us to
register their shares on demand beginning October 27, 2000. Following our
acquisition of Riverbed, the former Riverbed stockholders will become parties to
this agreement. We describe the terms of this agreement in further detail in
"Transactions Between Aether and its Officers, Directors or Significant
Stockholders" on page 69.
                                       90
<PAGE>   242

ANTI-TAKEOVER PROVISIONS OF DELAWARE LAW AND CHARTER PROVISIONS

     Our certificate of incorporation and bylaws contain provisions that are
intended to enhance the likelihood of continuity and stability in the
composition of our board of directors and in the polices formulated by our board
of directors. In addition, provisions of Delaware law may hinder or delay an
attempted takeover of Aether other than through negotiation with our board of
directors. These provisions could have the effect of discouraging attempts to
acquire us or remove incumbent management even if some or a majority of our
stockholders believe this action to be in their best interest, including
attempts that might result in the stockholders' receiving a premium over the
market price for the shares of common stock held by stockholders.

     Removal and replacement of directors.  Under our certificate of
incorporation and bylaws, directors may only be removed with cause. In addition,
a majority of the directors then in office can fill board vacancies and
newly-created directorships resulting from any increase in the size of the board
of directors, even if those directors do not constitute a quorum or only one
director is left in office. These provisions could prevent stockholders,
including parties who want to take over or acquire us, from removing incumbent
directors without cause and filling the resulting vacancies with their own
nominees.

     Advance notice provisions for stockholder proposals and stockholder
nominations of directors.  The bylaws establish an advance notice procedure
regarding stockholder proposals and nominations for director. The advance notice
procedure will not apply to proposals by our board of directors or management.
Any stockholder that wishes to make a proposal or nominate a director for
election at an annual meeting must deliver us notice of the proposal or the
nomination not less than 45 days nor more than 90 days before the first
anniversary of the proxy statement for the preceding year's annual meeting. For
a special meeting, the notice must generally be delivered not less than 70 days
nor more than 90 days before a special meeting or ten days following the day on
which public announcement of the meeting is first made. This advance notice
proposal could prevent someone interested in acquiring us from proposing actions
that could facilitate the takeover.

     Special meetings of stockholders and actions in lieu of a meeting.  Our
certificate of incorporation and bylaws permit special meetings of the
stockholders to be called only by the board of directors, the chairman of the
board or the president or holders of at least 50% of our securities that are
outstanding and entitled to vote generally in an election of directors. The
stockholders may take action by written consent in lieu of a meeting only if
such consent is signed by all stockholders. These provisions may make it more
difficult for stockholders to take actions opposed by the board of directors.

     Authorized but unissued shares.  Without further stockholder approval, we
can issue shares of common stock and preferred stock up to the number of shares
authorized for issuance in our certificate of incorporation, except as limited
by Nasdaq rules. We could use these additional shares for a variety of corporate
purposes. These purposes include future public offerings to raise additional
capital, corporate acquisitions and employee benefit plans. Our ability to issue
these shares of common stock and preferred stock could make it more difficult,
or discourage an attempt, to obtain control of Aether by means of a proxy
contest, tender offer, merger or otherwise.

     Amendment of bylaws.  The Delaware General Corporation Law generally
provides that the affirmative vote of a majority of the shares entitled to vote
on any matter is required to amend a corporation's certificate of incorporation
or bylaws, unless the corporation's certificate of incorporation or bylaws, as
the case may be, requires a greater percentage. Our certificate of incorporation
and bylaws require the affirmative vote of the holders of at least 66 2/3% of
our outstanding voting stock to amend or repeal our bylaws. Our bylaws may also
be amended or repealed by a simple majority vote of the board of directors.

     Section 203 of Delaware Law.  In addition to the foregoing provisions of
our certificate of incorporation and bylaws, we will be subject to the
provisions of Section 203 of the Delaware General Corporation Law. In general,
the statute prohibits a publicly-held Delaware corporation from engaging in a
"business combination" with an "interested stockholder" for a period of three
years after the date that the

                                       91
<PAGE>   243

person became an interested stockholder unless (with exceptions) the business
combination or the transaction in which the person became an interested
stockholder is approved in a prescribed manner. Generally, a "business
combination" includes a merger, asset or stock sale or other transaction
resulting in a financial benefit to the stockholder, and an "interested
stockholder" is a person who, together with affiliates and associates, owns (or
within three years prior, did own) 15% or more of the corporation's outstanding
voting stock. This provision may have the effect of delaying, deferring or
preventing a change in control of Aether without further action by the
stockholders. Transactions with NexGen or Telcom-ATI Investors or their
affiliates are not covered by this provision.

     Our stock option plan generally provides for assumption of our plan or
substitution of an equivalent option of a successor corporation or,
alternatively, at the discretion of the board of directors, exercise of some or
all of the options stock, including non-vested shares, or acceleration of
vesting of shares issued pursuant to stock grants, upon a change of control or
similar event. The ability to accelerate vesting may make a takeover more
expensive and thus discourage a takeover attempt.

WARRANTS

     As of the date of this prospectus, warrants were outstanding for the
purchase of 2,068,665 shares of common stock. Of these warrants, warrants for
1,000,000 shares are exercisable at a price of $1.60 per share and 175,000
warrants are exercisable at a price of $4.00 per share. 3Com holds the remaining
warrants to purchase 893,665 shares at a price of $.01 per share. The warrants
exercisable for $1.60 per share and the warrants exercisable for $4.00 per share
are currently exercisable and remain exercisable until June 2002. The remaining
warrants become exercisable from time to time upon the satisfaction of
conditions described on page 68 of this prospectus.

TRANSFER AGENT AND REGISTRAR

     The transfer agent and registrar for our common stock is BankBoston, N.A.

LISTING

     Our shares of common stock are quoted on the Nasdaq National Market under
the symbol "AETH."

                                       92
<PAGE>   244

             U.S. FEDERAL INCOME TAX CONSIDERATIONS TO U.S. HOLDERS

     The following is a summary of the material U.S. federal income tax
considerations relating to the purchase, ownership and disposition of the notes
and common stock into which the notes may be converted. This summary is based
upon the Internal Revenue Code of 1986, as amended (the "Code"), existing and
proposed Treasury Regulations, and judicial decisions and administrative
interpretations thereunder, all as of the date hereof, all of which are subject
to change, possibly with retroactive effect. There can be no assurance that the
Internal Revenue Service (the "IRS") will not challenge one or more of the tax
results described herein, and we have not obtained, nor do we intend to obtain,
a ruling from the IRS with respect to the U.S. federal income tax consequences
of acquiring or holding notes or common stock.

     This summary:

     - does not purport to be a complete analysis of all the potential tax
       considerations that may be relevant to holders in light of their
       particular circumstances, such as the alternative minimum tax provisions
       of the Code,

     - deals only with holders that will hold notes and common stock into which
       notes may be converted as "capital assets" within the meaning of Section
       1221 of the Code,

     - does not address tax considerations applicable to investors that may be
       subject to special tax rules, such as banks, tax-exempt organizations,
       insurance companies, dealers in securities or currencies, or persons that
       will hold notes as a position in a hedging transaction, "straddle," or
       "conversion transaction" for tax purposes,

     - discusses only the tax considerations applicable to the initial
       purchasers of the notes who purchase the notes at their "issue price" as
       defined in Section 1273 of the Code and does not discuss the tax
       considerations applicable to subsequent purchasers of the notes,

     - does not address the tax consequences arising under the laws of any
       foreign, state or local jurisdiction, and

     - is limited only to U.S. Holders, as defined below.

     For purposes of this summary, the term "U.S. Holder" means a beneficial
owner of a note or common stock that is for U.S. federal income tax purposes:

     - a citizen or resident of the United States,

     - a corporation or other entity created or organized in or under the laws
       of the United States or any political subdivision thereof,

     - an estate the income of which is subject to U.S. federal income taxation
       regardless of its source, or

     - a trust subject to the primary supervision of a U.S. Court and the
       control of one or more U.S. persons.

     If a partnership holds notes, the tax treatment of a partner will generally
depend upon the status of the partner and upon the activities of the
partnership. Partners of partnerships holding notes or common stock should
consult their tax advisors.

     WE URGE YOU TO CONSULT YOUR OWN TAX ADVISORS REGARDING THE FEDERAL, STATE,
LOCAL AND FOREIGN TAX CONSEQUENCES OF OWNERSHIP AND DISPOSITION OF THE NOTES,
INCLUDING CONVERSION OF THE NOTES, AND THE COMMON STOCK INTO WHICH THE NOTES MAY
BE CONVERTED AND THE EFFECT YOUR PARTICULAR CIRCUMSTANCES MAY HAVE ON SUCH TAX
CONSEQUENCES.

                                       93
<PAGE>   245

PAYMENTS OF INTEREST

     Interest on a note will generally be taxable to a U.S. Holder as ordinary
income at the time it accrues or is received in accordance with the U.S.
Holder's method of accounting for federal income tax purposes. The notes will
not generally be treated as bearing original issue discount for federal income
tax purposes.

SALE, EXCHANGE OR RETIREMENT OF NOTES

     Upon the sale, exchange or retirement of a note, a U.S. Holder will
recognize taxable gain or loss equal to the difference between such holder's
adjusted tax basis in the note and the amount realized on the sale, exchange or
retirement (including any additional payment received upon a provisional
redemption but excluding amounts representing interest not previously included
in income). A U.S. Holder's adjusted tax basis in a note will generally equal
the cost of the note to such holder. In general, gain or loss realized on the
sale, exchange or retirement of a note will be capital gain or loss. Payments
attributable to accrued interest which you have not yet included in income will
be taxed as ordinary interest income.

     Prospective investors should consult their tax advisors regarding the
treatment of capital gains (which may be taxed at lower rates than ordinary
income for taxpayers who are individuals, trust or estates and have held their
notes for more than one year) and losses (the deductibility of which is subject
to limitations).

CONVERSION OF NOTES

     A U.S. Holder's conversion of a note into common stock will generally not
be a taxable event, except for (i) common stock you receive with respect to
interest that has accrued but not been included in income, (ii) any cash you
receive instead of a fractional share of common stock, as described below, and
(iii) any cash you receive as an additional payment if you convert your notes
after receiving notice of a provisional redemption, to the extent described
below. Upon a U.S. Holder's conversion of a note into common stock, common stock
attributable to interest that has accrued but not been included in income will
be taxable to the U.S. Holder as ordinary interest income. The receipt of cash
in lieu of a fractional share of common stock should generally result in capital
gain or loss measured by the difference between the cash received for the
fractional share interest and the U.S. Holder's basis in the fractional share
interest, with such capital gain or loss being taxable as described above in
"-- Sale, Exchange or Retirement of Notes". Although the treatment of the cash
payment that we will be required to make in connection with a conversion
following a notice of provisional redemption is not entirely clear, such
payments will likely be taxable to U.S. Holders as capital gain. It is possible,
however, that those payments could be taxable to U.S. Holders as ordinary
income, or even as, in whole or in part, a nontaxable return of capital with a
corresponding reduction in the basis of the common stock received in the
conversion.

     A U.S. Holder's basis in the common stock received on conversion of a note
will be the same as the U.S. Holder's basis in the note at the time of the
conversion, reduced by any tax basis allocable to a fractional share and by the
basis reduction, if any, arising from a provisional redemption cash payment
described above. The holding period for the common stock received on conversion
will include the holding period of the note converted. However, a U.S. Holder's
tax basis in shares of common stock attributable to accrued interest as
described above generally will equal the amount of such accrued interest
included in income, and the holding period of such shares will commence with the
conversion.

OWNERSHIP AND DISPOSITION OF COMMON STOCK

     Dividends, if any, paid on the common stock generally will be includable in
the income of a U.S. Holder as ordinary income to the extent of the U.S.
Holder's ratable share of our current or accumulated earnings and profits.
Dividends paid to holders that are U.S. corporations may qualify for the
dividends received deduction. To the extent, if any, that a U.S. Holder receives
distributions on shares of common stock that would otherwise constitute
dividends for U.S. federal income tax purposes but that exceed our current and
accumulated earnings and profits, such distributions will be treated first as a
non-taxable
                                       94
<PAGE>   246

return of capital, reducing the holder's basis in the shares of common stock.
Any such distributions in excess of the holder's basis in the shares of common
stock generally will be treated as capital gain.

     Upon a sale or exchange of common stock, a U.S. Holder generally will
recognize capital gain or capital loss equal to the difference between the
amount realized on such sale or exchange and the holder's adjusted tax basis in
such shares. Prospective investors should consult their tax advisors regarding
the treatment of capital gains (which may be taxed at lower rates than ordinary
income for taxpayers who are individuals, trust or estates and have held their
common stock for more than one year) and losses (the deductibility of which is
subject to limitations).

     Adjustment of Conversion Rate.  If at any time we make a distribution of
property to shareholders that would be taxable to such shareholders as a
dividend for federal income tax purposes (for example, distributions of
evidences of indebtedness or our assets, but generally not stock dividends or
rights to subscribe for common stock) and, pursuant to the anti-dilution
provisions of the Indenture, the Conversion Rate of the notes is increased, such
increase may be deemed to be the payment of a taxable dividend to U.S. Holders
of notes under Section 305 of the Code and the Treasury Regulations issued
thereunder. If the Conversion Rate is increased at our discretion or in certain
other circumstances, such increase also may be deemed to be the payment of a
taxable dividend to U.S. Holders of notes. Moreover, in certain other
circumstances, the absence of such an adjustment to the Conversion Rate of the
notes may result in a taxable dividend to the holders of common stock.

INFORMATION REPORTING REQUIREMENTS AND BACKUP WITHHOLDING

     Information reporting will apply to payments of interest or dividends made
by us on, or the proceeds of the sale or other disposition of, the notes or
shares of common stock with respect to certain noncorporate U.S. Holders, and
backup withholding at a rate of 31 percent may apply unless the recipient of
such payment supplies a taxpayer identification number, certified under
penalties of perjury, as well as certain other information to the payor, or the
recipient otherwise establishes an exemption from backup withholding. Any amount
withheld under the backup withholding rules is allowable as a credit against the
U.S. Holder's federal income tax, provided that the required information is
provided to the IRS.

                                       95
<PAGE>   247

                        SHARES ELIGIBLE FOR FUTURE SALE

     Future sales of substantial amounts of common stock, including shares
issued upon exercise of outstanding options and warrants or conversion of
outstanding convertible notes, in the public market following this offering
could adversely affect market prices prevailing from time to time and could
impair our ability to raise capital through sale of our equity securities. Sales
of substantial amounts of our common stock in the public market after the
restrictions lapse could adversely affect the prevailing market price and our
ability to raise the equity capital in the future.

     As of February 15, 2000, assuming the completion of the concurrent common
stock offering and our pending acquisition of Riverbed, we would have
outstanding 34,509,687 shares of common stock. Of these shares, 10,414,187
shares (including the 3,000,000 shares to be sold in the concurrent common stock
offering (10,573,395 shares if the underwriters' over-allotment option is
exercised in full)), will be freely tradable in the public market without
restriction under the Securities Act, unless the shares are held by "affiliates"
of Aether, as that term is defined in Rule 144 under the Securities Act.

     Of the 34,509,687 shares outstanding upon completion of the concurrent
common stock offering and our pending acquisition of Riverbed, 24,095,500 will
be "restricted securities" as that term is defined under Rule 144. We issued and
sold these restricted securities in private transactions in reliance on
exemptions from registration under the Securities Act. Restricted securities may
be sold in the public market only if they are registered or if they qualify for
an exemption from registration under Rule 144 or Rule 701 under the Securities
Act, as summarized below.

     Pursuant to "lock-up" agreements, all directors of Aether have agreed with
the underwriters not to offer, sell, contract to sell, grant any option to
purchase or otherwise dispose of any of the 1,466,440 shares they hold or have
the right to acquire (or additional shares they may acquire) for a period of 90
days from the date of this prospectus. Pursuant to "lock-up" agreements, major
stockholders and all the executive officers of Aether have agreed with the
underwriters not to offer, sell, contract to sell, grant any option to purchase
or otherwise dispose of any of the 25,776,079 shares they hold or have the right
to acquire (or additional shares they may acquire) until October 21, 2000. We
also have entered into an agreement with the underwriters that we will not
offer, sell or otherwise dispose of common stock for a period of 90 days from
the date of this prospectus. However, Merrill Lynch & Co. may in its sole
discretion, at any time without notice, consent to the release all or any
portion of the shares subject to lock-up agreements.

     Taking into account the lock-up agreements, and assuming Merrill Lynch &
Co. does not release stockholders from these agreements, the following shares
will be eligible for sale in the public market at the following times:

     - on the date of this prospectus, 10,414,187 shares (10,573,395 shares if
       the underwriters' over-allotment option is exercised in full) will be
       immediately available for sale in the public market;

     - 90 days after the date of the prospectus, approximately 19,250 shares
       will be eligible for sale;

     - on October 26, 2000, 19,671,646 shares will be eligible for sale under
       Rule 144; and

     - at various times after October 26, 2000, 4,423,854 shares will be
       eligible for sale under Rule 144 from time to time.

     In general, under Rule 144, after the expiration of the lock-up period, a
person who has beneficially owned restricted securities for at least one year
would be entitled to sell, within any three-month period, a number of shares
that does not exceed the greater of:

     - 1% of the then-outstanding shares of common stock; or

     - the average weekly trading volume of the common stock during the four
       calendar weeks preceding the sale.

                                       96
<PAGE>   248

     Sales under Rule 144 are also subject to manner of sale and notice
requirements and to the availability of current public information about Aether.
Under Rule 144(k), a person who has not been our affiliate at any time during
the three months before a sale and who has beneficially owned the shares
proposed to be sold for at least two years can sell these shares without
complying with the manner of sale, public information, volume limitation or
notice provisions of Rule 144.

     Through February 15, 2000, we have outstanding options and warrants to
purchase 4,012,574 shares of common stock to specified persons pursuant to our
equity incentive plan. We also will be issuing options to acquire approximately
862,480 shares of our common stock in connection with the acquisition of
Riverbed. We have filed a registration statement on Form S-8 to register
5,400,000 shares of common stock reserved for issuance under our equity
incentive plan. See "Management -- Executive Compensation" on page 62. Shares
issued under the foregoing plan may be sold in the open market, subject, in the
case of some holders, to the Rule 144 limitations applicable to affiliates, the
lock-up agreements and vesting restrictions imposed by us.

     In addition, following this offering, the holders of 23,920,501 shares of
outstanding common stock will, under some circumstances, have rights to require
us to register their shares for future sale. See "Description of Capital
Stock -- Registration Rights of Stockholders" on page 90.

                                       97
<PAGE>   249

                                  UNDERWRITING

     We intend to offer our notes through the underwriters. Merrill Lynch,
Pierce, Fenner & Smith Incorporated, FleetBoston Robertson Stephens Inc.,
Donaldson, Lufkin & Jenrette Securities Corporation, U.S. Bancorp Piper Jaffray
Inc., Bear, Stearns & Co. Inc. and Friedman, Billings, Ramsey & Co., Inc. are
acting as representatives of the underwriters named below. Subject to the terms
and conditions contained in a purchase agreement between us and the
underwriters, we have agreed to sell to the underwriters, and the underwriters
severally have agreed to purchase from us, the aggregate principal amount of the
notes listed opposite their names below.

<TABLE>
<CAPTION>
                                                               PRINCIPAL
UNDERWRITER                                                      AMOUNT
- -----------                                                   ------------
<S>                                                           <C>
Merrill Lynch, Pierce, Fenner & Smith
             Incorporated...................................  $
FleetBoston Robertson Stephens Inc. ........................  $
Donaldson, Lufkin & Jenrette Securities Corporation.........  $
U.S. Bancorp Piper Jaffray Inc. ............................  $
Bear, Stearns & Co. Inc. ...................................  $
Friedman, Billings, Ramsey & Co., Inc.......................  $
                                                              ------------
             Total..........................................  $200,000,000
                                                              ============
</TABLE>

     The underwriters have agreed to purchase all of the notes sold pursuant to
the terms and conditions of the purchase agreement if any of these notes are
purchased. If an underwriter defaults, the purchase agreement provides that the
purchase commitments of the non-defaulting underwriters may be increased or the
purchase agreement may be terminated.

     We have agreed to indemnify the underwriters against certain liabilities,
including liabilities under the Securities Act, or to contribute to payments the
underwriters may be required to make in respect of those liabilities.

     The underwriters are offering the notes, subject to prior sale, when, as
and if issued to and accepted by them, subject to approval of legal matters by
their counsel, including the validity of the notes, and other conditions
contained in the purchase agreement, such as the receipt by the underwriters of
officer's certificates and legal opinions. The underwriters reserve the right to
withdraw, cancel or modify offers to the public and to reject orders in whole or
in part.

COMMISSIONS AND DISCOUNTS

     The underwriters have advised us that they propose initially to offer the
notes to the public at the public offering price on the cover page of this
prospectus, and to dealers at that price less a concession not in excess of
     % of the principal amount of the notes. The underwriters may allow, and the
dealers may reallow, a discount not in excess of      % of the principal amount
of the notes to other dealers. After the public offering, the public offering
price, concession and discount may be changed.

     The following table shows the public offering price, underwriting discount
and proceeds before expenses to Aether. The information assumes either no
exercise or full exercise by the underwriters of their over-allotment option.

<TABLE>
<CAPTION>
                                              PER DEBENTURE    WITHOUT OPTION    WITH OPTION
                                              -------------    --------------    -----------
<S>                                           <C>              <C>               <C>
Public offering price.......................        $                $                $
Underwriting discount.......................        $                $                $
Proceeds, before expenses, to Aether........        $                $                $
</TABLE>

     The expenses of the offering, not including the underwriting discount, are
estimated to be $1.2 million and are payable by Aether.

                                       98
<PAGE>   250

OVER-ALLOTMENT OPTION

     We have granted options to the underwriters to purchase up to $30,000,000
of the notes at the public offering price on the cover page of this prospectus,
less the underwriting discount. The underwriters may exercise these options for
30 days from the date of this prospectus solely to cover over-allotments. If the
underwriters exercise these options, each underwriter will be obligated, subject
to conditions contained in the purchase agreement, to purchase a number of
additional notes proportionate to such underwriter's initial amount reflected in
the above table.

NO SALES OF SIMILAR SECURITIES

     We have agreed, with exceptions, not to sell or transfer any convertible
debt or preferred securities for 90 days after the date of this prospectus
without first obtaining the written consent of Merrill Lynch. Specifically we
have agreed not to directly or indirectly

     - offer, pledge, sell or contract to sell any convertible debt or preferred
       securities,

     - sell any option or contract to purchase any convertible debt or preferred
       securities,

     - purchase any option or contract to sell any convertible debt or preferred
       securities,

     - grant any option, right or warrant for the sale of any convertible debt
       or preferred securities,

     - file a registration statement for any convertible debt or preferred
       securities, or

     - lend or otherwise dispose of or transfer any convertible debt or
       preferred securities.

NO STOCK EXCHANGE LISTING OR QUOTATION ON THE NASDAQ NATIONAL MARKET

     The notes are a new issue of securities with no established trading market.
We do not intend to apply for listing of the notes on any national securities
exchange or for quotation of the notes on any automated dealer quotation system.
The underwriters have advised us that they presently intend to make a market in
the notes after completion of this offering. However, they are under no
obligation to do so and may discontinue any market-making activities at any time
without any notice. We cannot assure the liquidity of the trading market for the
notes or that an active public market for the notes will develop. If an active
public trading market for the notes does not develop, the market price and
liquidity of the notes may be adversely affected. If the notes are traded, they
may trade at a discount from their initial offering price, depending on
prevailing interest rates, the market for similar securities, our performance
and other factors.

PRICE STABILIZATION AND SHORT POSITIONS

     Until the distribution of the notes is completed, SEC rules may limit the
underwriters from bidding for and purchasing the notes. However, the
underwriters may engage in transactions that stabilize the price of the notes
such as bids or purchases to peg, fix or maintain the price of the these
securities.

     If the underwriters create a short position in the notes in connection with
the offering, i.e., if they sell more notes than are listed on the cover page of
this prospectus, the underwriters may reduce that short position by purchasing
notes in the open market. The underwriters may also elect to reduce any short
position by exercising all or part of the over-allotment option described above.
Purchases of a security to stabilize the price or to reduce a short position may
cause the price of the security to be higher than it might be in the absence of
such purchases.

     Neither we nor any of the underwriters makes any representation or
prediction as to the direction or magnitude of any effect that the transactions
described above may have on the price of the notes. In addition, neither we nor
any of the underwriters makes any representation that the underwriters will
engage in these transactions or that these transactions, once commenced, will
not be discontinued without notice.

                                       99
<PAGE>   251

PASSIVE MARKET MAKING

     In connection with the concurrent offering of common stock, underwriters
and selling group members may engage in passive market making transactions in
the common stock on the Nasdaq National Market in accordance with Rule 103 of
Regulation M under the Exchange Act during a period before the commencement of
offers or sales of common stock and extending through the completion of
distribution. A passive market maker must display its bid at a price not in
excess of the highest independent bid of that security. However, if all
independent bids are lowered below the passive market maker's bid, that bid must
then be lowered when specified purchase limits are exceeded.

OTHER RELATIONSHIPS

     Some of the underwriters and their affiliates have engaged in, and may in
the future engage in, investment banking and other commercial dealings in the
ordinary course of business with us. They have received or may receive customary
fees and commissions for these transactions.

                                       100
<PAGE>   252

                                 LEGAL MATTERS

     The validity of the notes offered hereby and the common stock issuable upon
conversion of such notes will be passed upon for Aether by Wilmer, Cutler &
Pickering, Washington, D.C. George P. Stamas, a consultant to Wilmer, Cutler &
Pickering, is a director of Aether. Mr. Stamas owns options to purchase 11,250
shares of our common stock, and he holds a non-voting interest in Telcom-ATI
Investors, which owns 7,026,948 shares of common stock. Certain legal matters in
connection with this offering will be passed upon for the underwriters by Hogan
& Hartson L.L.P., Washington, D.C.

                                    EXPERTS

     The consolidated financial statements and schedule of Aether Systems, Inc.
as of December 31, 1998 and 1999, and for each of the years in the three-year
period ended December 31, 1999 have been included herein and in the registration
statement in reliance upon the reports of KPMG LLP, independent certified public
accountants, appearing elsewhere herein, and upon the authority of said firm as
experts in accounting and auditing.

     The financial statements of Mobeo, Inc. as of December 31, 1997 and 1998
and for each of the three years in the period ended December 31, 1998 included
in this prospectus have been included in reliance on the report of
PricewaterhouseCoopers LLP, independent accountants, given on the authority of
said firm as experts in auditing and accounting.

     The financial statements of Riverbed Technologies, Inc. as of December 31,
1998 and 1999, and for the period from October 21, 1998 (date of inception) to
December 31, 1998 and for the year ended December 31, 1999, have been included
herein and in the registration statement in reliance upon the report of KPMG
LLP, independent certified public accountants, appearing elsewhere herein, and
upon authority of said firm as experts in accounting and auditing.

                      WHERE YOU CAN FIND MORE INFORMATION

     We are subject to the informational requirements of the Securities Exchange
Act and we file reports, proxy and information statements and other information
with the Commission. You may read and copy all or any portion of the reports,
proxy and information statements or other information we file at the
Commission's principal office in Washington, D.C., and copies of all or any part
thereof may be obtained from the Public Reference Section of the Commission, 450
Fifth Street, N.W., Washington, D.C. 20549, and at the Commission's regional
offices located at Citicorp Center, 500 West Madison Street, Suite 1400,
Chicago, Illinois 60661 and at 7 World Trade Center, 13th Floor, New York, New
York 10048 after payment of fees prescribed by the Commission. Please call the
Commission at 1-800-SEC-0330 for further information on operation of the public
reference rooms. The Commission also maintains a World Wide Web site which
provides online access to reports, proxy and information statements and other
information regarding registrants that file electronically with the Commission
at the address http://www.sec.gov.

     We have filed with the Commission a Registration Statement on Form S-1
under the Securities Act with respect to the notes to be sold in this offering.
This prospectus does not contain all of the information set forth in the
registration statement and the exhibits to the registration statement. For
further information with respect to Aether Systems, Inc. and our notes offered
hereby, reference is made to the Registration Statement and the exhibits filed
as a part of the Registration Statement. Statements contained in this prospectus
concerning the contents of any contract or any other document are not
necessarily complete; reference is made in each instance to the copy of such
contract or any other document filed as an exhibit to the registration
statement. Each such statement is qualified in all respects by such reference to
such exhibit. The registration statement, including exhibits thereto, may be
inspected without charge at the locations described above, or obtained upon
payment of fees prescribed by the Commission.

                                       101
<PAGE>   253

                         INDEX TO FINANCIAL STATEMENTS

                              AETHER SYSTEMS, INC.

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Independent Auditors' Report................................   F-2
Consolidated Balance Sheets as of December 31, 1998 and
  1999......................................................   F-3
Consolidated Statements of Operations and Other
  Comprehensive Loss for the years ended December 31, 1997,
  1998 and 1999.............................................   F-4
Consolidated Statements of Stockholders' Equity for the
  years ended December 31, 1997, 1998 and 1999..............   F-5
Consolidated Statements of Cash Flows for the years ended
  December 31, 1997, 1998 and 1999..........................   F-6
Notes to Consolidated Financial Statements..................   F-7
</TABLE>

                                  MOBEO, INC.

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Report of Independent Accountants...........................  F-20
Balance Sheets as of December 31, 1997 and 1998.............  F-21
Statements of Operations for the years ended December 31,
  1996, 1997 and 1998.......................................  F-22
Statements of Changes in Stockholders' Equity (Deficit) for
  the years ended December 31, 1996, 1997 and 1998..........  F-23
Statements of Cash Flows for the years ended December 31,
  1996, 1997 and 1998.......................................  F-24
Notes to Financial Statements...............................  F-25
</TABLE>

                          RIVERBED TECHNOLOGIES, INC.

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Independent Auditors' Report................................  F-31
Balance Sheets as of December 31, 1998 and 1999.............  F-32
Statements of Operations for the period from October 21,
  1998 (Date of Inception) to December 31, 1998 and for the
  year ended December 31, 1999..............................  F-33
Statements of Stockholders' Equity (Deficit) for the period
  from October 21, 1998 (Date of Inception) to December 31,
  1998 and for the year ended December 31, 1999.............  F-34
Statements of Cash Flows for the period from October 21,
  1998 (Date of Inception) to December 31, 1998 and for the
  year ended December 31, 1999..............................  F-35
Notes to Financial Statements...............................  F-36
</TABLE>

                         UNAUDITED PRO FORMA CONDENSED
                       CONSOLIDATED FINANCIAL INFORMATION

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Description of Unaudited Pro Forma Condensed Consolidated
  Financial Information.....................................  F-44
Unaudited Pro Forma Condensed Consolidated Balance Sheet as
  of December 31, 1999......................................  F-45
Unaudited Pro Forma Condensed Consolidated Balance Sheet
  Adjustments for Completed Transactions as of December 31,
  1999......................................................  F-47
Unaudited Pro Forma Condensed Consolidated Balance Sheet
  Adjustments for Pending Transaction as of December 31,
  1999......................................................  F-49
Unaudited Pro Forma Condensed Consolidated Statement of
  Operations for the year ended
  December 31, 1999.........................................  F-51
Unaudited Pro Forma Condensed Consolidated Statement of
  Operations Adjustments for Completed Transactions for the
  year December 31, 1999....................................  F-53
Unaudited Pro Forma Condensed Consolidated Statement of
  Operations Adjustments for Pending Transaction for the
  year December 31, 1999....................................  F-55
</TABLE>

                                       F-1
<PAGE>   254

                          INDEPENDENT AUDITORS' REPORT

The Board of Directors and Stockholders
Aether Systems, Inc.:

     We have audited the accompanying consolidated balance sheets of Aether
Systems, Inc. and subsidiary as of December 31, 1998 and 1999, and the related
consolidated statements of operations and other comprehensive loss,
stockholders' equity and cash flows for each of the years in the three-year
period ended December 31, 1999. These consolidated financial statements are the
responsibility of the Company's management. Our responsibility is to express an
opinion on these consolidated financial statements based on our audits.

     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

     In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the financial position of Aether
Systems, Inc. and subsidiary as of December 31, 1998 and 1999, and the results
of their operations and their cash flows for each of the years in the three-year
period ended December 31, 1999, in conformity with generally accepted accounting
principles.

                                          KPMG LLP

McLean, Virginia
February 9, 2000

                                       F-2
<PAGE>   255

                              AETHER SYSTEMS, INC.

                          CONSOLIDATED BALANCE SHEETS

                                     ASSETS

<TABLE>
<CAPTION>
                                                                    DECEMBER 31,
                                                              -------------------------
                                                                 1998          1999
                                                              ----------   ------------
<S>                                                           <C>          <C>
Current assets:
  Cash and cash equivalents.................................  $1,755,350   $ 78,541,792
  Short-term investments....................................   6,191,287      2,091,962
  Trade accounts receivable, net of allowance for doubtful
     accounts of $157,061 and $56,371 at December 31, 1998
     and 1999, respectively.................................     118,489      1,002,845
  Inventory, net of allowance for obsolescence of $169,630
     and $115,153 at December 31, 1998 and 1999,
     respectively...........................................     143,617        688,494
  Prepaid expenses and other current assets.................      45,646      4,994,965
                                                              ----------   ------------
          Total current assets..............................   8,254,389     87,320,058
Property and equipment, net.................................     510,437      2,795,920
Intangible assets, net......................................          --     12,209,442
Other assets................................................          --        208,698
                                                              ----------   ------------
                                                              $8,764,826   $102,534,118
                                                              ==========   ============

                LIABILITIES, MEMBERS' CAPITAL AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable..........................................  $  195,930   $  1,425,435
  Accrued expenses..........................................     288,350      1,619,947
  Accrued employee compensation and benefits................     250,975        971,110
  Deferred revenue..........................................          --        175,193
                                                              ----------   ------------
          Total current liabilities.........................     735,255      4,191,685
Members' capital............................................   8,029,571             --
Stockholders' equity:
  Preferred stock, $0.01 par value; 1,000,000 shares
     authorized; 0 shares issued and outstanding at December
     31, 1999,..............................................          --             --
  Common stock, $0.01 par value; 75,000,000 shares
     authorized; 27,154,398 issued and outstanding at
     December 31, 1999......................................          --        271,543
  Additional paid-in-capital................................          --    120,892,478
  Accumulated deficit.......................................          --    (22,613,640)
  Notes receivable from stockholder.........................          --       (137,879)
  Unrealized loss on investments available for sale.........          --        (70,069)
                                                              ----------   ------------
          Total stockholders' equity........................          --     98,342,433
                                                              ----------   ------------
          Commitments and contingencies
                                                              $8,764,826   $102,534,118
                                                              ==========   ============
</TABLE>

          See accompanying notes to consolidated financial statements.

                                       F-3
<PAGE>   256

                              AETHER SYSTEMS, INC.

       CONSOLIDATED STATEMENTS OF OPERATIONS AND OTHER COMPREHENSIVE LOSS

<TABLE>
<CAPTION>
                                                               YEAR ENDED DECEMBER 31,
                                                       ----------------------------------------
                                                          1997          1998           1999
                                                       -----------   -----------   ------------
<S>                                                    <C>           <C>           <C>
Subscriber revenue...................................  $   161,400   $   549,057   $  3,731,792
Engineering services revenue.........................    1,624,733       963,165      2,594,476
                                                       -----------   -----------   ------------
          Total revenue..............................    1,786,133     1,512,222      6,326,268
Cost of subscriber revenue...........................      447,480       797,165      2,109,807
Cost of engineering services revenue.................      846,140       304,137      1,366,426
                                                       -----------   -----------   ------------
          Total cost of revenue......................    1,293,620     1,101,302      3,476,233
                                                       -----------   -----------   ------------
          Gross profit...............................      492,513       410,920      2,850,035
                                                       -----------   -----------   ------------
Operating expenses:
  Research and development (exclusive of option and
     warrant expense of $0, $0, and $150,288 for the
     year ended December 31, 1997, 1998 and 1999,
     respectively)...................................      733,630     1,267,320      2,613,726
  General and administrative (exclusive of option and
     warrant expense of $40,277, $32,580, and
     $18,004,623 for the years ended December 31,
     1997, 1998, and 1999, respectively).............    1,504,250     2,773,332      5,891,504
  Selling and marketing (exclusive of option and
     warrant expense of $0, $0 and $1,043,298 for the
     years ended December 31, 1997, 1998, and 1999,
     respectively)...................................      333,191       840,455      2,095,074
  Depreciation and amortization......................      189,160       264,685      1,089,013
  Option and warrant expense.........................       40,277        32,580     19,198,209
                                                       -----------   -----------   ------------
                                                         2,800,508     5,178,372     30,887,526
                                                       -----------   -----------   ------------
          Operating loss.............................   (2,307,995)   (4,767,452)   (28,037,491)
Other income (expense):
  Interest income....................................        7,788       140,479        996,436
  Interest expense...................................           --       (70,171)    (1,056,718)
  Equity in losses of investments....................     (144,825)                  (2,425,000)
  Realized gain (loss) on sale of short-term
     investments.....................................           --         3,872       (168,721)
  Realized loss on sale of investment................     (302,145)           --             --
                                                       -----------   -----------   ------------
          Net loss...................................  $(2,747,177)  $(4,693,272)  $(30,691,494)
Other comprehensive loss-unrealized holding gain
  (loss) on investments available for sale...........           --       (58,030)       (12,039)
                                                       -----------   -----------   ------------
Comprehensive loss...................................  $(2,747,177)  $(4,751,302)  $(30,703,533)
                                                       ===========   ===========   ============
Pro forma statement of operations data (unaudited):
  Loss before income taxes, as reported..............  $(2,747,177)  $(4,693,272)  $(30,691,494)
  Pro forma income tax provision (benefit)...........           --            --             --
                                                       -----------   -----------   ------------
  Pro forma net loss.................................  $(2,747,177)  $(4,693,272)  $(30,691,494)
                                                       ===========   ===========   ============
  Pro forma net loss per share-basic and diluted.....  $     (0.22)  $     (0.29)  $      (1.45)
                                                       ===========   ===========   ============
  Pro forma weighted average shares outstanding-basic
     and diluted.....................................   12,655,901    15,916,383     21,207,225
                                                       ===========   ===========   ============
</TABLE>

          See accompanying notes to consolidated financial statements.

                                       F-4
<PAGE>   257

                              AETHER SYSTEMS, INC.

                CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
<TABLE>
<CAPTION>
                                                                                            NOTES
                                                            ADDITIONAL                   RECEIVABLE    UNREALIZED
                                    PREFERRED    COMMON      PAID-IN      ACCUMULATED       FROM         LOSS ON      MEMBERS'
                                      STOCK      STOCK       CAPITAL        DEFICIT      STOCKHOLDER   INVESTMENTS     CAPITAL
                                    ---------   --------   ------------   ------------   -----------   -----------   -----------
<S>                                 <C>         <C>        <C>            <C>            <C>           <C>           <C>
Balance at January 1, 1997........     $--      $     --   $         --   $         --    $      --     $     --     $ 1,100,866
 Issuance of member units in
   February 1997..................      --            --             --             --           --           --       1,000,000
 Issuance of member units in
   December 1997..................      --            --             --             --           --           --         690,369
 Unit option and warrant
   expense........................      --            --             --             --           --           --          40,277
 Note receivable from member......      --            --             --             --           --           --         (10,000)
 Net loss.........................      --            --             --             --           --           --      (2,747,177)
                                       ---      --------   ------------   ------------    ---------     --------     -----------
Balance at December 31, 1997......      --            --             --             --           --           --          74,335
 Issuance of member units in
   January 1998...................      --            --             --             --           --           --       1,499,314
 Issuance of warrants in
   June 1998......................      --            --             --             --           --           --          50,000
 Exercise of warrants in August
   1998...........................      --            --             --             --           --           --              56
 Conversion of note payable and
   issuance of member units in
   August 1998....................      --            --             --             --           --           --         252,467
 Issuance of member units in
   August 1998....................      --            --             --             --           --           --       5,000,000
 Issuance of member units in
   October 1998...................      --            --             --             --           --           --       6,000,000
 Unit option and warrant
   expense........................      --            --             --             --           --           --          32,580
 Unrealized loss on investments
   available for sale.............      --            --             --             --           --                      (58,030)
 Note receivable from member......      --            --             --             --           --           --        (127,879)
 Net loss.........................      --            --             --             --           --           --      (4,693,272)
                                       ---      --------   ------------   ------------    ---------     --------     -----------
Balance at December 31, 1998......      --            --             --             --           --                    8,029,571
 Issuance of replacement options
   to Mobeo, Inc. employees.......      --            --             --             --           --           --         374,000
 Exercise of unit options and
   warrants.......................      --            --             --             --           --           --          70,000
 Option and warrant expense.......      --            --             --             --           --           --       2,323,698
 Net loss -- pre merger...........      --            --             --             --           --           --      (8,077,854)
 Merger of Aether Technologies
   International, L.L.C. into
   Aether Systems, Inc. in October
   1999...........................      --       200,670      2,714,654             --     (137,879)     (58,030)     (2,719,415)
 Net proceeds of initial public
   offering.......................      --        69,000    101,044,831             --           --           --
 Unrealized loss on investments
   available for sale.............      --            --             --             --           --      (12,039)             --
 Option and warrant expense.......      --            --     16,874,511             --           --           --              --
 Exercise of stock options........      --         1,873        258,482             --           --           --              --
 Net loss -- post merger..........      --            --             --    (22,613,640)          --           --              --
                                       ---      --------   ------------   ------------    ---------     --------     -----------
Balance at December 31, 1999......     $--      $271,543   $120,892,478   $(22,613,640)   $(137,879)    $(70,069)    $        --
                                       ===      ========   ============   ============    =========     ========     ===========

<CAPTION>

                                       TOTAL
                                    ------------
<S>                                 <C>
Balance at January 1, 1997........  $  1,100,866
 Issuance of member units in
   February 1997..................     1,000,000
 Issuance of member units in
   December 1997..................       690,369
 Unit option and warrant
   expense........................        40,277
 Note receivable from member......       (10,000)
 Net loss.........................    (2,747,177)
                                    ------------
Balance at December 31, 1997......        74,335
 Issuance of member units in
   January 1998...................     1,499,314
 Issuance of warrants in
   June 1998......................        50,000
 Exercise of warrants in August
   1998...........................            56
 Conversion of note payable and
   issuance of member units in
   August 1998....................       252,467
 Issuance of member units in
   August 1998....................     5,000,000
 Issuance of member units in
   October 1998...................     6,000,000
 Unit option and warrant
   expense........................        32,580
 Unrealized loss on investments
   available for sale.............       (58,030)
 Note receivable from member......      (127,879)
 Net loss.........................    (4,693,272)
                                    ------------
Balance at December 31, 1998......     8,029,571
 Issuance of replacement options
   to Mobeo, Inc. employees.......       374,000
 Exercise of unit options and
   warrants.......................        70,000
 Option and warrant expense.......     2,323,698
 Net loss -- pre merger...........    (8,077,854)
 Merger of Aether Technologies
   International, L.L.C. into
   Aether Systems, Inc. in October
   1999...........................            --
 Net proceeds of initial public
   offering.......................   101,113,831
 Unrealized loss on investments
   available for sale.............       (12,039)
 Option and warrant expense.......    16,874,511
 Exercise of stock options........       260,355
 Net loss -- post merger..........   (22,613,640)
                                    ------------
Balance at December 31, 1999......  $ 98,342,433
                                    ============
</TABLE>

          See accompanying notes to consolidated financial statements.

                                       F-5
<PAGE>   258

                              AETHER SYSTEMS, INC.

                     CONSOLIDATED STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                                      YEAR ENDED DECEMBER 31,
                                                              ----------------------------------------
                                                                 1997          1998           1999
                                                              -----------   -----------   ------------
<S>                                                           <C>           <C>           <C>
Cash flows from operating activities:
  Net loss..................................................  $(2,747,177)  $(4,693,272)  $(30,691,494)
  Adjustments to reconcile net loss to net cash used by
    operating activities:
    Depreciation and amortization...........................      189,160       264,685      1,089,013
    Provision (recovery) for doubtful accounts..............           --       157,061        (59,530)
    Provision (recovery) for inventory obsolescence.........           --       169,630        (54,477)
    Realized (gain) loss on sale of short-term
     investments............................................           --        (3,872)       168,721
    Equity in losses of investments.........................      144,825            --      2,425,000
    Realized loss on sale of investment.....................      302,145            --             --
    Issuance of warrants....................................           --        50,000             --
    Option and warrant expense..............................       40,277        32,580     19,198,209
    Changes in assets and liabilities:
      (Increase) decrease in trade accounts receivable......       74,812      (153,417)    (1,730,942)
      Increase in inventory.................................           --      (313,247)      (490,400)
      (Increase) decrease in prepaid expenses and other
       current assets.......................................        3,828       (30,529)    (3,785,442)
      Increase (decrease) in accounts payable...............       67,360        83,421       (376,810)
      Increase in accrued expenses and employee compensation
       and benefits.........................................      272,622       216,457      2,051,732
      Increase (decrease) in deferred revenue...............      162,500      (162,500)       175,193
                                                              -----------   -----------   ------------
         Net cash used by operating activities..............   (1,489,648)   (4,383,003)   (12,081,227)
                                                              -----------   -----------   ------------
Cash flows (used) by investing activities:
  Sales of short-term investments...........................       49,977     1,295,525     12,640,562
  Purchases of short-term investments.......................           --    (7,535,118)    (8,721,997)
  Acquisition of Mobeo, Inc., net of cash acquired..........           --            --    (11,547,976)
  Purchases of property and equipment.......................     (441,700)     (228,274)    (2,447,106)
  Investment in OmniSky, Inc................................           --            --     (2,500,000)
  Long-term investments.....................................      (23,000)           --             --
  Proceeds from sale of investment in joint venture.........      205,000            --             --
                                                              -----------   -----------   ------------
         Net cash used in investing activities..............     (209,723)   (6,467,867)   (12,576,517)
                                                              -----------   -----------   ------------
Cash flows provided by financing activities:
  Issuance of member units..................................    1,690,369    12,501,781             --
  Proceeds from issuance of common stock....................           --            --    101,113,831
  Repayments from member....................................      (50,000)           --             --
  Proceeds from note payable................................      150,000       500,000             --
  Repayments on notes payable...............................           --      (400,000)            --
  Proceeds from credit facility.............................           --            --     14,830,000
  Repayments of credit facility.............................           --            --    (14,830,000)
  Issuance of notes receivable from member..................      (10,000)     (127,879)            --
  Exercise of options and warrants..........................           --            56        330,355
                                                              -----------   -----------   ------------
         Net cash provided by financing activities..........    1,780,369    12,473,958    101,444,186
                                                              -----------   -----------   ------------
         Net increase in cash and cash equivalents..........       80,998     1,623,088     76,786,442
Cash and cash equivalents, at beginning of period...........       51,264       132,262      1,755,350
                                                              -----------   -----------   ------------
Cash and cash equivalents, at end of period.................  $   132,262   $ 1,755,350   $ 78,541,792
                                                              ===========   ===========   ============
Supplemental disclosure of cash flow information:
  Cash paid during the year for interest....................  $     3,894   $    20,171   $  1,026,643
                                                              ===========   ===========   ============
</TABLE>

- ---------------
Supplemental disclosure of noncash investing and financing activities:
    In 1997, the Company made a $26,457 investment in Navox, Inc. by forgiving a
     trade account receivable of an equal amount.
    In 1998, a member converted a $250,000 promissory note payable into
     membership units.
    In 1998 and 1999, the Company incurred unrealized holding losses associated
     with its investments available for sale totaling $58,030 and $12,039. These
     amounts have been reported as reductions in members' capital and
     stockholders' equity, respectively.
    In September 1999, the Company issued 18,442 unit options (46,105 shares)
     valued at $374,000 as part of the cost to acquire Mobeo, Inc. This amount
     has been reported as an increase in members' capital.
    In October 1999, approximately $1.1 million of trade receivables owed to the
     Company by OmniSky, Inc. were settled against amounts due in connection
     with the purchase of 20,000 modems from OmniSky, Inc.

          See accompanying notes to consolidated financial statements.

                                       F-6
<PAGE>   259

                              AETHER SYSTEMS, INC.

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
(1)  ORGANIZATION AND DESCRIPTION OF BUSINESS

     Aether Systems, Inc. and its subsidiary (the "Company") designs, develops,
sells and supports wireless data services and systems enabling people to use
handheld devices for mobile data communications and real-time transactions. The
Company operates in a highly competitive environment subject to rapid
technological change and emergence of new technology. Although management
believes its services are transferable to emerging technologies, rapid changes
in technology could have an adverse financial impact on the Company.

     The Company expects to expand its operations through continued capital
investment in new systems and services and through strategic acquisitions. The
Company has a limited operating history and has incurred net losses since its
inception. The Company expects to continue to incur significant sales and
marketing, systems development and administrative expenses. The Company may
require additional capital in the future to meet its operating and capital
needs.

(2)  MERGER AND INITIAL PUBLIC OFFERING

     The Company is the successor to the business formerly conducted by Aether
Systems, L.L.C. ("Aether") (previously Aether Technologies International,
L.L.C.), which was formed in January, 1996. Effective October 26, 1999, in
connection with the Company's initial public offering of common stock, Aether
merged with and into Aether Systems, Inc. The Company is the surviving company
in the merger, and owns all of the assets and rights and is subject to all of
the obligations and liabilities of Aether. Immediately prior to the merger, each
member of the Company contributed its membership units in Aether Systems, L.L.C.
to Aether Systems, Inc., a newly formed Delaware corporation, in exchange for
two and one-half shares of common stock of Aether Systems, Inc. Effective with
the merger, the Company converted to a Subchapter C Corporation under the
Internal Revenue Code of 1986 as amended.

     On October 26, 1999, the Company completed its initial public offering,
which involved the sale of 6,900,000 shares of common stock at $16.00 per share,
including 900,000 shares from the exercise of the underwriters' over-allotment
option, at the initial public offering price less underwriting discounts and
offering expenses. Net proceeds to the Company after deducting underwriting
discounts, commissions and other expenses of the offering were approximately
$101.1 million.

(3)  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

  (a) Principles of Consolidation

     The consolidated financial statements include the accounts of Aether
Systems, Inc. and its wholly owned subsidiary, Mobeo, Inc. All significant
intercompany transactions and balances have been eliminated in consolidation.

  (b) Revenue Recognition

     The Company derives subscriber revenue from the provision of real-time
access to information from selected financial markets integrated into existing
wireless communication platforms. Subscriber revenue consists of monthly fixed
charges for usage and equipment and is recognized as the service is provided on
a monthly basis and a one time non-refundable activation fee which is recognized
upon service activation. Direct activation costs are expensed as incurred.
Certain of the Company's customers are billed in advance with revenue deferred
and recognized on a monthly basis over the term of the agreement. Also included
in subscriber revenue are market exchange fees for access to financial
information from the securities exchanges and markets, which are recognized as
the service is provided. Engineering services revenue is derived from the
provision of wireless integration consulting under time-and-materials and
fixed-fee contracts. Revenue on time-and-materials contracts is recognized as
services are performed. Revenue on fixed-fee contracts is recognized on the
percentage-of-completion method based on costs incurred in

                                       F-7
<PAGE>   260
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

relation to total estimated costs. Anticipated contract losses are recognized as
soon as they become known and estimable.

  (c) Cost of Revenues

     Cost of subscriber revenue consists primarily of airtime costs, financial
data costs, wireless handheld device costs, and securities exchange and market
fees. Since the Company's service agreements are generally for a one-year period
and subject to cancellation, non-payment and non-return risk, the Company
expenses the cost of wireless handheld devices upon shipment to the customer.
Cost of engineering services revenue consists of cash compensation and related
costs for engineering personnel and materials.

  (d) Cash and Cash Equivalents

     Cash equivalents include all highly liquid investments purchased with
original maturities of three months or less. Cash equivalents consist of
approximately $193,000 and $5,521,000 in overnight repurchase agreements,
$1,562,000 and $68,831,000 in money market accounts, and $0 and $3,979,000 in
commercial paper at December 31, 1998 and 1999, respectively.

  (e) Short-term Investments

     Short-term investments consist of highly liquid investments with original
maturities greater than three months and less than one year and those
longer-term investments that the Company expects to liquidate within twelve
months. The Company has classified its short-term investments as "available for
sale" and carries such investments at fair value. Unrealized gains (losses) are
excluded from earnings and are reported as a separate component of other
comprehensive income until realized. Realized gains and losses from the sale of
these investments are determined on a specific identification basis.

  (f) Fair Value of Financial Instruments

     The carrying amounts of the Company's financial instruments, which include
cash equivalents, accounts receivable, accounts payable and accrued expenses
approximate their fair values due to the relatively short duration of the
instruments.

  (g) Concentration of Credit Risk

     Financial instruments that potentially subject the Company to a
concentration of credit risk consist of accounts receivable. The Company extends
credit to its customers on an unsecured basis in the normal course of business.

  (h) Inventory

     Inventory, net of allowance for obsolete and slow-moving inventory,
consists primarily of handheld and laptop computers, pagers, wireless modems,
and accessories and is stated at the lower of cost or market. Cost is determined
using the first-in, first-out (FIFO) method. The inventory of the Company is
subject to rapid technological changes which could have an adverse impact on its
realization in future periods. In addition, there are a limited number of
suppliers of the Company's inventory.

  (i) Property and Equipment

     Property and equipment are stated at cost. Depreciation is calculated using
the straight-line method over the estimated useful lives of the assets, which
range from three to seven years. The costs of leasehold improvements are
capitalized and amortized using the straight-line method over the shorter of the
lease term or the estimated useful life of the asset.

                                       F-8
<PAGE>   261
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

  (j) Investment in OmniSky, Inc.

     The Company uses the equity method of accounting for advances to and
earnings and losses of its investment in OmniSky, Inc.

  (k) Goodwill and Recovery of Long-Lived Assets

     Cost in excess of the fair value of tangible and identifiable intangible
net assets acquired is included in intangible assets and is amortized on a
straight-line basis over seven years.

     The Company's policy is to review its long-lived assets for impairment
whenever events or changes in circumstances indicate that the carrying amount
may not be recoverable. The Company recognizes an impairment loss when the sum
of the expected future undiscounted cash flows is less than the carrying amount
of the asset. The measurement of the impairment losses to be recognized is based
upon the difference between the fair value and the carrying amount of the
assets.

  (l) Stock Options and Warrants

     The Company accounts for equity-based compensation arrangements in
accordance with the provisions of Accounting Principle Board ("APB") Opinion No.
25, "Accounting for Stock Issued to Employees," and related interpretations, and
complies with the disclosure provisions of Statement of Financial Accounting
Standards ("SFAS") No. 123, "Accounting for Stock-Based Compensation." Under APB
No. 25, compensation expense is based upon the difference, if any, on the date
of grant, between the fair value of the Company's stock and the exercise price.
All equity-based awards to non-employees are accounted for at their fair value
in accordance with SFAS No. 123.

  (m) Pro Forma Income (Loss) Data (Unaudited)

     The accompanying unaudited pro forma information has been prepared as if
the Company was treated as Subchapter C Corporation for Federal and state income
tax purposes from January 1, 1997. The Company has provided no income taxes on a
pro forma basis due to the losses incurred in all periods.

     The Company computes net income (loss) per share in accordance with SFAS
No. 128, "Earnings Per Share," and SEC Staff Accounting Bulletin No. 98 ("SAB
98"). Under the provisions of SFAS No. 128 and SAB 98, basic net income (loss)
per share is computed by the dividing the net income (loss) available to common
stockholders for the period by the weighted average number of common shares
outstanding during the period. Diluted net income (loss) per share is computed
by dividing the net income (loss) for the period by the weighted average number
of common and dilutive common equivalent shares outstanding during the period.
Pro forma basic and diluted net loss per share has been calculated assuming that
the capital structure established at the date of the initial public offering was
in effect during the periods presented. As the Company had a net loss in each of
the periods presented, pro forma basic and diluted net loss per share are the
same.

  (n) Research and Development

     Research and development costs are expensed as incurred.

  (o) Advertising Expense

     Advertising costs are expensed as incurred. Advertising expense was
approximately $248,000, $504,000, and $933,000 for the years ended December 31,
1997, 1998 and 1999, respectively.

  (p) Income Taxes

     The Company recognizes income taxes using the asset and liability method,
in accordance with Statement of Financial Accounting Standards ("SFAS") No. 109.
Under the asset and liability method, deferred tax assets and liabilities are
recognized for the future tax consequences attributable to differences

                                       F-9
<PAGE>   262
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

between the financial statement carrying amounts of existing assets and
liabilities and their respective tax bases. Deferred tax assets and liabilities
are measured using enacted tax rates expected to apply to taxable income in the
years in which those temporary differences are expected to be recovered or
settled. The effect of a tax rate change on deferred tax assets and liabilities
is recognized in income in the period that includes the enactment date.

     Prior to October 26, 1999, Aether had elected limited liability status and,
as such, was not directly subject to Federal and state income taxes. Rather, the
members were responsible for income taxes on their proportionate share of
taxable income and entitled to their proportionate share of tax deductions and
tax credits.

  (q) Use of Estimates

     The preparation of consolidated financial statements in conformity with
generally accepted accounting principles requires management to make estimates
and assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the dates of the consolidated
financial statements and the reported amounts of revenue and expenses during the
reporting period. Actual results could differ from those estimates.

  (r) Other Comprehensive Loss

     Effective January 1, 1998, the Company adopted SFAS No. 130, "Reporting
Comprehensive Income", which established standards for reporting and displaying
comprehensive income and its components in financial statements. Comprehensive
income, as defined, includes changes in equity of a business enterprise during a
period from transactions and other events and circumstances from non-owner
sources. Other comprehensive income refers to revenue, expenses, gains and
losses that under generally accepted accounting principles are included in
comprehensive income, but excluded from net income.

     For the years ended December 31, 1998 and 1999, other comprehensive income
(loss) consists of unrealized losses on investments available for sale.

  (s) Recent Accounting Pronouncements

     In June 1998, the FASB issued SFAS No. 133, "Accounting for Derivative
Instruments and Hedging Activities." The new standard establishes accounting and
reporting standards for derivative instruments, including certain derivative
instruments embedded in other contracts and for hedging activities. This
statement, as amended, is effective for all fiscal quarters beginning after June
15, 2000. The Company does not expect SFAS No. 133 to have a material affect on
its financial position or results of operations.

(4)  ACQUISITION OF MOBEO, INC.

     On August 19, 1999, the Company entered into a purchase agreement to
acquire all the outstanding common stock of Mobeo, Inc. ("Mobeo") for an
aggregate purchase price consisting of cash of approximately $11.5 million,
including acquisition costs of approximately $112,000, and 18,442 unit options
(46,105 shares) with an exercise price of $12.00 per unit ($4.80 per share)
valued at approximately $374,000. The acquisition was completed on September 28,
1999. Mobeo provides employees and customers at major banks and financial
institutions with continuous pricing information and news headlines for foreign
exchange, government securities, and commodity markets on wireless handheld
devices. Additionally, the Company entered into two-year advisory service
agreements with two former owners of Mobeo which provided for the grant of an
aggregate 125,000 unit options (312,500 shares) with an exercise price of $15.00
per unit ($6.00 per share). The Company also issued 22,000 options (55,000
shares) at an exercise price of $6.00 per unit ($2.40 per share) and 30,000
options (75,000 shares) at an exercise price of $12.00 per unit ($4.80 per
share) to employees of Mobeo. The Company has recorded option and warrant
expense of approximately $418,000 in 1999 associated with

                                      F-10
<PAGE>   263
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

these options and expects to record an additional $2.9 million in option and
warrant expense over the remaining service and vesting periods.

     The acquisition has been accounted for under the purchase method of
accounting and, accordingly, the assets acquired and liabilities assumed have
been recorded at their estimated fair value as of the acquisition date. The
allocation of the purchase price is summarized as follows:

<TABLE>
<S>                                                           <C>
Current assets..............................................  $   258,000
Property and equipment......................................      372,000
Other assets................................................      133,000
Current liabilities.........................................   (1,606,000)
Goodwill and other intangibles..............................   12,765,000
                                                              -----------
Total consideration paid....................................  $11,922,000
                                                              ===========
</TABLE>

     The following summary, prepared on a pro forma basis, presents the results
of operations (unaudited) of the Company as if the Mobeo acquisition had been
completed as of January 1, 1998:

<TABLE>
<CAPTION>
                                                                    (UNAUDITED)
                                                       DECEMBER 31, 1998   DECEMBER 31, 1999
                                                       -----------------   -----------------
<S>                                                    <C>                 <C>
Revenue..............................................     $10,093,008        $ 13,836,410
Net loss.............................................      (6,842,574)        (31,749,078)
Net loss per share -- basic and diluted..............            (.43)              (1.50)
</TABLE>

     The unaudited pro forma results of operations are not necessarily
indicative of what actually would have occurred if Mobeo had been owned for the
entire periods presented or a projection of the Company's results of operations
for any future period.

(5)  INVESTMENT IN OMNISKY, INC.

     On August 9, 1999, the Company entered into a new venture with 3Com
Corporation ("3Com"), forming a new Company called OpenSky, which was later
renamed OmniSky, Inc. ("OmniSky"). OmniSky was formed to develop wireless
Internet access, e-mail and electronic commerce services that address
opportunities in the emerging consumer and business mass markets. The Company
contributed a perpetual, non-exclusive, non-assignable, worldwide license to
certain proprietary software in exchange for a 26% equity interest in OmniSky in
the form of 7,000,000 shares of Series A Preferred Stock and an option to
purchase an additional 3,000,000 shares of Series A Preferred Stock for an
additional $2.5 million. Upon exercising the option, the Company would increase
its ownership in OmniSky to 33% on a fully diluted basis. On November 9, 1999,
the Company exercised its option to acquire these additional shares. The chief
executive officer of the Company serves as a member of OmniSky's board of
directors. The Company provides engineering services to OmniSky under an
agreement in the amount of $3.0 million through June 2000. As of December 31,
1999, the Company has recognized $2.2 million in engineering services revenue
under the OmniSky agreement. This amount represents 86% of engineering services
revenue and 35% of total revenue for the year ended December 31, 1999. The
agreement also provides for OmniSky to pay $1.50 per month per subscriber for
the use of the Company's network operations center. The Company has the right to
offer OmniSky's services to its subscribers for a monthly fee of $3.00 per
subscriber. There has been no activity as of December 31, 1999 under these
provisions of the agreement.

     The Company accounts for its investment in OmniSky under the equity method
of accounting. The Company recorded $2.4 million in expenses through December
31, 1999, to reflect its proportionate share of the losses in OmniSky based upon
unaudited financial information provided by OmniSky.

     During 1999, OmniSky, Inc. reported a net loss of approximately $5.7
million (unaudited) and had net assets of $9.7 million (unaudited) as of
December 31, 1999.
                                      F-11
<PAGE>   264
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

     In October 1999, the Company agreed to purchase 25,000 Minstrel V modems
from OmniSky for $230 per modem. OmniSky has an exclusive buying arrangement
with Novatel for Minstrel V modems, which began in December 1999 and will run
through March of 2000. The Company purchased 20,000 of the 25,000 for cash of
$3.5 million and cancellation of $1.1 million of trade receivables owed to the
Company by Omnisky. An additional $1.2 million will be paid to OmniSky, Inc. for
the remaining 5,000 modems after the delivery of the initial 20,000 modems,
which began in November 1999 and will continue through April of 2000. As of
December 31, 1999, the Company has recorded prepaid expenses of approximately
$4.5 million associated with this agreement. The Company received approximately
$58,000 of modems during 1999.

     On January 18, 2000, the Company entered into a Series B Preferred Stock
Purchase Agreement, whereby the Company purchased 1,439,809 shares of Series B
preferred stock of OmniSky for an aggregate purchase price of approximately $6.7
million, consisting of cash of approximately $6.1 million and the cancellation
of approximately $600,000 of indebtedness owed to the Company by OmniSky for
engineering services. The investment was made to maintain the Company's 33
percent ownership in OmniSky. The Company's per share purchase price was the
same as the other Series B Preferred Stock investors.

(6)  SHORT-TERM INVESTMENTS

     As of December 31, 1998, short-term available for sale investments consists
of:

<TABLE>
<CAPTION>
                                                      GROSS           GROSS
                                     AMORTIZED     UNREALIZED       UNREALIZED        FAIR
                                        COST      HOLDING GAINS   HOLDING LOSSES     VALUE
                                     ----------   -------------   --------------   ----------
<S>                                  <C>          <C>             <C>              <C>
U.S. Treasury securities...........  $1,929,810      $    --         $(21,677)     $1,908,133
Corporate debt securities..........   4,319,507       11,881          (48,234)      4,283,154
                                     ----------      -------         --------      ----------
                                     $6,249,317      $11,881         $(69,911)     $6,191,287
                                     ==========      =======         ========      ==========
</TABLE>

     Maturities of debt securities classified as available for sale were as
follows at December 31, 1998:

<TABLE>
<CAPTION>
                                                              AMORTIZED       FAIR
                                                                 COST        VALUE
                                                              ----------   ----------
<S>                                                           <C>          <C>
Due within one year.........................................  $2,124,838   $2,129,084
Due after one year through five years.......................   1,184,890    1,157,964
Due after five years through ten years......................   1,435,695    1,412,043
Due after ten years.........................................   1,503,894    1,492,196
                                                              ----------   ----------
                                                              $6,249,317   $6,191,287
                                                              ==========   ==========
</TABLE>

     As of December 31, 1999, short-term available for sale investments consists
of:

<TABLE>
<CAPTION>
                                                      GROSS           GROSS
                                     AMORTIZED     UNREALIZED       UNREALIZED        FAIR
                                        COST      HOLDING GAINS   HOLDING LOSSES     VALUE
                                     ----------   -------------   --------------   ----------
<S>                                  <C>          <C>             <C>              <C>
U.S. Treasury securities...........  $1,828,460        $95           $(45,895)     $1,782,660
Corporate debt securities..........     333,571         --            (24,269)        309,302
                                     ----------        ---           --------      ----------
                                     $2,162,031        $95           $(70,164)     $2,091,962
                                     ==========        ===           ========      ==========
</TABLE>

                                      F-12
<PAGE>   265
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

     Maturities of debt securities classified as available for sale were as
follows at December 31, 1999:

<TABLE>
<CAPTION>
                                                              AMORTIZED       FAIR
                                                                 COST        VALUE
                                                              ----------   ----------
<S>                                                           <C>          <C>
Due within one year.........................................  $  325,076   $  326,177
Due after one year through five years.......................     855,751      834,434
Due after five years through ten years......................     717,944      667,257
Due after ten years.........................................     263,260      264,094
                                                              ----------   ----------
                                                              $2,162,031   $2,091,962
                                                              ==========   ==========
</TABLE>

(7)  PROPERTY AND EQUIPMENT

     Property and equipment consists of the following:

<TABLE>
<CAPTION>
                                                                       DECEMBER 31,
                                                   ESTIMATED     ------------------------
                                                  USEFUL LIVES      1998         1999
                                                  ------------   ----------   -----------
<S>                                               <C>            <C>          <C>
Furniture and fixtures..........................      7 Years    $  102,345   $   593,030
Computer and equipment..........................  3 - 5 Years       684,328     2,113,229
Software........................................      3 Years       175,000       175,000
Leasehold improvements..........................      5 Years        47,854       946,927
                                                  -----------    ----------   -----------
                                                                  1,009,527     3,828,186
Less depreciation and amortization..............                   (499,090)   (1,032,266)
                                                                 ----------   -----------
                                                                 $  510,437   $ 2,795,920
                                                                 ==========   ===========
</TABLE>

(8)  INTANGIBLE ASSETS

     Intangible assets consists of the following:

<TABLE>
<CAPTION>
                                                               ESTIMATED     DECEMBER 31,
                                                              USEFUL LIVES       1999
                                                              ------------   ------------
<S>                                                           <C>            <C>
Goodwill....................................................    7 Years      $  6,165,279
Acquired subscribers........................................    5 Years         6,400,000
Assembled workforce.........................................    3 Years           200,000
                                                                             ------------
                                                                               12,765,279
Less accumulated amortization...............................                     (555,837)
                                                                             ------------
                                                                             $ 12,209,442
                                                                             ============
</TABLE>

     Goodwill represents the purchase price in excess of the fair value of the
tangible and identifiable intangible assets acquired.

(9)  NOTES PAYABLE TO MEMBERS

     The Company had an unsecured note payable of $150,000 as of December 31,
1997 due to one of its members, Telcom Ventures LLC ("Telcom Ventures"). The
note carried interest at a rate of 7.5 percent per annum and all principal and
accrued interest was due in January 1999, or earlier upon the occurrence of
specified criteria. The note payable, plus accrued interest, was repaid in 1998.

     In June 1998, the Company borrowed $250,000 from one of its members,
Pyramid Ventures, Inc. ("Pyramid") under a convertible promissory note. The note
was unsecured, bore interest at 8 percent per annum, and was convertible into
membership units at the option of the member. In August 1998, the

                                      F-13
<PAGE>   266
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

member elected to convert the note and accrued interest of $2,467 into 57,180
membership units (142,950 shares) in accordance with its terms.

     In June 1998, the Company borrowed $250,000 from another one of its
members, Telcom Ventures, under a similar convertible promissory note. All
principal and accrued interest was paid by the Company in August 1998.

     In connection with the convertible promissory notes, the Company granted
warrants to purchase 5,656 member units (14,140 shares) at an exercise price of
$0.01 per unit to Pyramid and Telcom Ventures (note 13). The estimated value of
the warrants on the grant date of $50,000 was recognized in interest expense in
1998. Pyramid exercised its warrants to purchase 5,656 member units (14,140
shares) in August 1998. In August 1999, Telcom Ventures exercised its warrants
to purchase 5,656 member units (14,140 shares).

     All outstanding membership units were subsequently exchanged for common
stock in connection with the Company's initial public offering, effective
October 26, 1999 (Note 2).

(10)  INCOME TAXES

     Effective October 26, 1999, in connection with the Company's initial public
offering of common stock, Aether merged with and into the Company and the merged
entity became a Subchapter C Corporation under the Internal Revenue Code of
1986. As a result, the Company recorded a deferred tax expense of approximately
$1.4 million, principally relating to intangible assets other than goodwill
acquired as part of the Mobeo acquisition prior to becoming a Subchapter C
Corporation, offset, in part, by deferred tax assets associated with option and
warrant expense. The Company recorded a deferred tax benefit of $1.4 million
related to losses generated subsequent to the change in tax status.

     The Company has provided no income taxes on a pro forma basis due to the
losses incurred in all periods.

     The tax effects of temporary differences that give rise to significant
portions of the deferred tax assets and liabilities at December 31, 1999, are
presented below:

<TABLE>
<CAPTION>
                     DECEMBER 31, 1999
                     -----------------
<S>                                                           <C>
Deferred tax assets:
  Net operating loss carryforwards..........................  $ 2,274,000
  Depreciation and amortization.............................       54,000
  Option and warrant expense................................    7,903,000
                                                              -----------
Gross deferred tax assets...................................  $10,231,000
Valuation allowance for deferred tax assets.................   (7,692,000)
                                                              -----------
Net deferred tax assets.....................................    2,539,000
                                                              -----------
Deferred tax liabilities:
  Allowance for doubtful accounts...........................       18,000
  Intangibles...............................................    2,521,000
                                                              -----------
Net deferred tax liabilities................................    2,539,000
                                                              -----------
Deferred income taxes, net..................................  $        --
                                                              -----------
</TABLE>

     As of December 31, 1999, the Company had Federal and state net operating
loss carryforwards of approximately $5,400,000 which expire in 2019.

     In addressing the realizability of deferred tax assets, management
considers whether it is more likely than not that some portion or all of the
deferred tax assets will not be realized. The ultimate realization of deferred
tax assets is dependent on the generation of future taxable income during the
periods in which

                                      F-14
<PAGE>   267
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

those temporary differences become deductible. Management considers the
scheduled reversal of deferred tax liabilities, projected future taxable income
and tax planning strategies in making this assessment.

(11)  LEASES

     The Company is obligated under noncancelable operating leases for office
space, that expire at various dates through 2010. Future minimum lease payments
under noncancelable operating leases are approximately as follows:

<TABLE>
<CAPTION>
                  YEAR ENDING DECEMBER 31,
                  ------------------------
<S>                                                           <C>
2000........................................................  $  648,000
2001........................................................     664,000
2002........................................................     676,000
2003........................................................     705,000
2004........................................................     736,000
Thereafter..................................................   3,866,000
                                                              ----------
Total minimum lease payments................................  $7,295,000
                                                              ==========
</TABLE>

     Rent expense under operating leases was approximately $84,000, $91,000, and
$282,000 for the years ended December 31, 1997, 1998 and 1999, respectively.

(12)  PENSION PLANS

     The Company has two defined contribution plans under Section 401(k) of the
Internal Revenue Code that provide for voluntary employee contributions of 1 to
15 percent of compensation for substantially all employees. The Company
contributed $4,000 to one of the plans for the year ended December 31, 1999.

(13)  STOCK OPTIONS AND WARRANTS

  (a) Options

     In 1996, the Company adopted a Unit Option Plan. In September 1999, the
Company adopted the 1999 Equity Incentive Plan (the "Plan") to replace the Unit
Option Plan. Under the 1999 Equity Incentive Plan, the Company has the ability
to grant options to acquire up to 5.4 million shares of common stock to its
employees, directors, and service providers. Options under the Plan generally
expire after ten years and normally vest over a period of up to three years.
Options are generally granted at an exercise price equal to the fair value on
the grant date.

     In June 1999, the Company entered into an employment agreement with its
Chief Executive Officer ("Executive"). As part of this agreement, the Executive
was granted 350,000 unit options (875,000 shares) at an exercise price of $4.00
per unit ($1.60 per share) and the right to grant an additional 50,000 unit
options (125,000 shares) at an exercise price of $4.00 per unit ($1.60 per
share) to other key executives. These options expire in June 2009. In September
1999, the Company granted the Executive an additional 70,000 unit options
(175,000 shares) at an exercise price of $10.00 per unit ($4.00 per share).
These options expire in September 2009. Both grants of options became fully
vested in October 1999, as a result of the completion of the Company's initial
public offering. In October 1999, the Company recorded option and warrant
expense of $16.5 million, which is equal to the difference between the fair
value of the shares of Aether System Inc.'s common stock and the exercise price
measured at the date of the initial public offering, times the number of
options.

     The Company recorded total option and warrant expense of $40,277, $32,580
and $19,198,209 in 1997, 1998, and 1999, respectively. The Company expects to
record an additional $5.9 million in option and warrant expense through June 30,
2002 for the difference between the exercise price and the fair market value of
the units or stock at the date of grant.

                                      F-15
<PAGE>   268
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

     The Company applies APB 25 and related interpretations in accounting for
its unit option plan. Had compensation cost been recognized consistent with SFAS
No. 123, the Company's net loss would have increased by $24,000, $41,000, and
$4,243,000 for 1997, 1998, and 1999, respectively.

     The per share weighted-average value of options granted by the Company
during 1997, 1998, and 1999 was $0.16, $0.55, and $9.21, respectively, on the
date of grant using the Black-Scholes option-pricing model. These amounts were
calculated using an expected option life of 3 years and volatility of zero for
options granted in 1997 and 1998. In 1999, an expected option life of four years
and volatility of 70 percent was used for option grants. In addition, the
calculations assumed a risk-free interest rate of 5.77 percent to 6.25 percent
in 1997, 4.55 percent to 5.51 percent in 1998, and 4.60 percent to 6.11 percent
in 1999.

     A summary of the stock option and warrant activity, as adjusted for the
exchange of unit options and warrants for stock options, is as follows:

<TABLE>
<CAPTION>
                                          1997                      1998                      1999
                                 -----------------------   -----------------------   -----------------------
                                              WEIGHTED-                 WEIGHTED-                 WEIGHTED-
                                               AVERAGE                   AVERAGE                   AVERAGE
                                              EXERCISE                  EXERCISE                  EXERCISE
                                  NUMBER        PRICE       NUMBER        PRICE       NUMBER        PRICE
                                 OF SHARES   (PER SHARE)   OF SHARES   (PER SHARE)   OF SHARES   (PER SHARE)
                                 ---------   -----------   ---------   -----------   ---------   -----------
<S>                              <C>         <C>           <C>         <C>           <C>         <C>
Outstanding at beginning of
  year.........................    693,438      $0.40      1,000,000      $0.40      1,545,000      $0.85
Options and warrants granted...    306,562      $0.40        604,688      $1.54      2,763,856      $6.19
Options exercised..............         --         --             --         --       (365,498)     $0.54
Options canceled...............         --         --        (59,688)     $0.40        (10,000)     $1.49
                                 ---------      -----      ---------      -----      ---------      -----
Outstanding at end of year.....  1,000,000      $0.40      1,545,000      $0.85      3,933,358      $4.48
                                 =========      =====      =========      =====      =========      =====
Options exercisable at
  year-end.....................    596,720      $0.40        991,093      $0.50      2,450,657      $2.13
                                 =========      =====      =========      =====      =========      =====
</TABLE>

     The following table summarizes information about stock options at December
31, 1999:

<TABLE>
<CAPTION>
                                  OPTIONS OUTSTANDING                         OPTIONS EXERCISABLE
                   --------------------------------------------------   -------------------------------
                                        WEIGHTED
                                         AVERAGE         WEIGHTED                          WEIGHTED
                                        REMAINING    AVERAGE EXERCISE    NUMBER AT     AVERAGE EXERCISE
RANGE OF EXERCISE      NUMBER AT       CONTRACTUAL        PRICE         DECEMBER 31,        PRICE
     PRICES        DECEMBER 31, 1999      LIFE         (PER SHARE)          1999         (PER SHARE)
- -----------------  -----------------   -----------   ----------------   ------------   ----------------
                                       (IN YEARS)
<S>                <C>                 <C>           <C>                <C>            <C>
$ 0.40 - $ 0.40          617,314           2.19           $ 0.40            591,219         $0.40
$ 1.49 - $ 8.00        3,085,044           8.36           $ 2.98          1,859,438         $2.68
$52.25 - $79.75          231,000           9.90           $35.34                 --            --
                      ----------                                         ----------
                       3,933,358           6.83           $ 4.48          2,450,657         $2.13
                      ==========                                         ==========
</TABLE>

  (b) Warrants Issued to Members

     The Company granted warrants to purchase an aggregate 11,312 member units
(28,280 shares) at an exercise price of $0.01 per unit to Telcom Ventures and
Pyramid, as consideration for obtaining short-term loans (note 9).

     In connection with the sale of membership units to 3Com, the Company
granted a conditional warrant to 3Com to purchase 357,466 member units (893,665
shares) at an exercise price of $0.01 per unit. 3Com vested in 57,466 units
(143,665 shares) in June 1999 upon completion of a joint sales and marketing
plan. As a result, the Company recorded option and warrant expense of
approximately $862,000. 3Com vests in the remaining 300,000 warrants (750,000
shares) as follows: 150,000 warrants (375,000 shares) upon the occurrence of the
Company obtaining $6 million in engineering services

                                      F-16
<PAGE>   269
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

revenue from opportunities introduced by 3Com and 150,000 warrants (375,000
shares) upon the Company obtaining 6,000 wireless service subscribers, all from
opportunities introduced by 3Com. If and when it becomes probable that 3Com will
attain the specified milestones necessary for the warrants to vest, the Company
will begin to record an expense reflecting the fair value of the warrants, which
will be determined in part based on the market price of the common stock. The
Company would begin to recognize this expense based on the probability that the
milestones would be achieved, continuing through the actual vesting date. The
Company would initially estimate the amount of the expense at the time of the
determination that achievement is probable, based in part on the market price of
the common stock at that time. At the time of the actual vesting, the fair value
of the warrant would be remeasured and, if different from the value used in
initially estimating the expense, the difference would be reflected as an
additional charge or credit at that time. As of December 31, 1999, the Company
believes that it is not yet probable that 3Com will attain the specified
milestones relating to the remaining warrants to purchase 750,000 shares and,
accordingly, no expense relating to these warrants has been recorded.

  (c) Notes Payable

     In September 1999, the Company entered into a $17,000,000 senior secured
credit facility with Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith
Incorporated. The credit facility was for a one-year term, with the possibility
of extension for an additional one-year term and accrued interest at a variable
rate. The credit facility was collateralized by substantially all of the assets
of the Company and contained certain financial covenants. In connection with the
credit facility, the Company granted warrants to Merrill Lynch Capital
Corporation to purchase up to 967,876 (2,419,690 shares) of the member units in
the Company which became exercisable for no consideration if the Company did not
repay the credit facility in a timely manner. On September 28, 1999, the Company
borrowed approximately $14,830,000 under the credit facility, primarily to pay
the purchase price of Mobeo. On October 26, 1999, the Company repaid the amount
outstanding under the credit facility and the warrants were canceled.

(14)  OTHER RELATED-PARTY TRANSACTIONS

  (a) Notes Receivable from Stockholder

     As of December 31, 1998 and 1999, the Company has amounts due from a
stockholder under short-term promissory notes of $137,879. The Company has
classified the notes as a reduction of stockholders' equity in the accompanying
consolidated statements of stockholders' equity. The notes are callable by the
Company at any time and bear interest at a rate of 7.5 percent per annum. The
notes and accrued interest were repaid in February 2000.

  (b) Consulting Agreements with Stockholders

     The Company derived approximately 34 percent and 39 percent of its revenue
for 1997 and 1998, respectively, from consulting services arrangements with one
and two of its stockholders, respectively. The Company had trade no accounts
receivable due from these stockholders as of December 31, 1998 and 1999,
respectively.

     As of December 31, 1997, the Company had received advances of $162,500 from
two of its members under consulting arrangements. This amount was recorded as
deferred revenue in the accompanying 1997 balance sheet, and was subsequently
recognized as revenue in 1998, when the related consulting services were
performed.

  (c) Purchases from Stockholder

     In 1998, the Company purchased approximately $560,000 of equipment and
inventory from a stockholder.

                                      F-17
<PAGE>   270
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

(15)  INVESTMENTS

     In February 1996, the Company made an investment of $750,000 to acquire a
20 percent interest in Real World Solutions, Inc. (RWS), a California company,
which was in the business of developing wireless middleware. The Company
accounted for its investment in RWS under the equity method and recorded its
proportionate share of losses generated by RWS. In July 1997, the Company sold
its interest in RWS to Puma Technology, Inc. (Puma), a Delaware company for
$205,000. The Company's carrying value of the investment in RWS as of the date
of sale was approximately $507,000 resulting in a realized loss on the sale of
the investment of approximately $302,000.

     Concurrently with the sale of the Company's investment in RWS to Puma, the
Company entered into an agreement with Puma for $175,000 to obtain perpetual
license rights for certain wireless middleware software. This amount was
capitalized and is being amortized over a three-year period.

     In December 1996, the Company made an investment of $48,000 in Navox, Inc.,
(Navox) a privately-held Delaware company which provides wireless communication,
location and security system development services. In June 1997, the Company
made an additional investment of $26,457 in Navox. The Company's investment
represents an approximate 5.5 percent interest in Navox, and includes
representation on Navox's board of directors. The Company accounts for its
investment in Navox under the equity method of accounting and records its
proportionate share of losses generated by Navox. The Company derived
approximately 50 percent and 2 percent of its revenue for 1997 and 1998,
respectively, under consulting arrangements with Navox. The Company had no trade
accounts receivables due from Navox as of December 31, 1998 and 1999,
respectively. The Company does not anticipate significant revenue from Navox in
the future.

(16)  RESERVED SHARE PROGRAM

     Prior to October 20, 1999, the effectiveness of the Company's registration
statement for its initial public offering, the Company sent a letter to
approximately 90 employees, officers and directors of the Company whom it had
designated as potential offerees of up to 390,000 shares of common stock in a
directed share program in connection with its initial public offering. These
materials were not accompanied by a preliminary prospectus and may have
constituted a prospectus that does not meet the requirements of the Securities
Act of 1933. If the mailing of these original materials did constitute a
violation of the Securities Act of 1933, the recipients of the letter who
purchased common stock in the initial public offering could have the right, for
a period of one year from the date of their purchase of common stock, to obtain
recovery of the consideration paid in connection with their purchase of common
stock or, if they have already sold the stock, sue the Company for damages
resulting from their purchase of common stock. These refunds or damages could
total up to approximately $6.2 million, based on the initial public offering
price of $16.00 per share, in the event that investors suffer a total loss of
their investment during this period and seek refunds or damages.

(17)  CONTINGENCY

     The Company has received two claims that it has infringed patents developed
by other parties. Management believes that these claims are without merit and
intends to contest them vigorously. If the Company is unsuccessful in its
defense, it could be liable for damages or could be required to enter into
costly royalty arrangements.

(18)  SUBSEQUENT EVENTS

  (a) Acquisition of LocusOne Communications, Inc.

     On February 3, 2000, the Company acquired all the outstanding common stock
and preferred stock of LocusOne Communications, Inc. ("LocusOne") for a purchase
price of approximately $40 million. LocusOne is a developer of wireless
communications for the supply chain management industry. The

                                      F-18
<PAGE>   271
                              AETHER SYSTEMS, INC.

                   NOTES TO FINANCIAL STATEMENTS-(CONTINUED)

acquisition will be accounted for under the purchase method of accounting.
Approximately $19.0 million of the purchase price is payable in the form of
non-interest bearing notes payable due no later than December 31, 2000.

  (b) Inciscent

     On February 7, 2000 the Company agreed to form a new company with
Metrocall, Inc., PSINet, Inc. and Hicks, Muse, Tate & Furst, Incorporated to be
called Inciscent. Inciscent will offer technology services to small and
medium-sized businesses and home office customers. The Company agreed to acquire
a 27.5% interest in Inciscent for $10 million. The Company also agreed to
acquire a 9.9% interest in Metrocall for $17 million.

  (c) Strategic Alliance with Reuters PLC

     On February 8, 2000, the Company entered into a non-binding letter of
intent with Reuters PLC to establish a new company focused on financial markets
in Europe. The Company plans to acquire a 60% interest in this new company for
$100 million.

  (d) Pending Acquisition of Riverbed Technologies, Inc.

     On February 9, 2000, the Company entered into an definitive merger
agreement to acquire Riverbed Technologies, Inc. ("Riverbed") for approximately
4,537,000 shares of common stock, plus the issuance of options to acquire
approximately 862,000 additional shares of common stock for replacement of
existing options of Riverbed's employees. Riverbed develops products to extend
the accessibility of applications and information from corporate networks and
databases to handheld devices. The acquisition will be accounted for under the
purchase method of accounting and is subject to regulatory approval and
shareholder vote by Riverbed shareholders.

                                      F-19
<PAGE>   272

                       REPORT OF INDEPENDENT ACCOUNTANTS

To the Board of Directors and Stockholders of Mobeo, Inc.

     In our opinion, the accompanying balance sheets and the related statements
of operations, changes in stockholders' equity (deficit) and cash flows, present
fairly, in all material respects, the financial position of Mobeo, Inc. at
December 31, 1997 and 1998, and the results of its operations and its cash flows
for the three years in the period ended December 31, 1998, in conformity with
generally accepted accounting principles. These financial statements are the
responsibility of the Company's management; our responsibility is to express an
opinion on these financial statements based on our audits. We conducted our
audits in accordance with generally accepted auditing standards which require
that we plan and perform the audit to obtain reasonable assurance about whether
the financial statements are free of material misstatement. An audit includes
examining, on a test basis, evidence supporting the amounts and disclosures in
the financial statements, assessing the accounting principles used and
significant estimates made by management, and evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for the opinion expressed above.

PricewaterhouseCoopers LLP
McLean, Virginia
March 10, 1999

                                      F-20
<PAGE>   273

                                  MOBEO, INC.

                                 BALANCE SHEETS

                                     ASSETS

<TABLE>
<CAPTION>
                                                                   DECEMBER 31,
                                                              -----------------------
                                                                 1997         1998
                                                              ----------   ----------
<S>                                                           <C>          <C>
Current assets:
  Cash and cash equivalents.................................  $  125,446   $  193,913
  Accounts receivable, net..................................     278,620      293,895
  Prepaid expenses and other................................      37,032       28,724
  Income tax refund receivable..............................      20,756       20,756
  Deferred income tax.......................................     142,365      186,549
                                                              ----------   ----------
          Total current assets..............................     604,219      723,837
Property and equipment, net.................................     321,876      405,148
Patents, net................................................          --       30,307
Deposits....................................................      24,475       23,609
Deferred income tax.........................................      71,476       14,542
                                                              ----------   ----------
          Total assets......................................  $1,022,046   $1,197,443
                                                              ==========   ==========

                   LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable..........................................  $  989,316   $1,130,184
  Accrued expenses..........................................     275,541      390,172
  Income tax payable........................................          --           --
  Capital lease obligations.................................      12,159           --
  Deferred revenue..........................................      71,220      104,170
                                                              ----------   ----------
          Total current liabilities.........................   1,348,236    1,624,526
                                                              ----------   ----------
Commitments and contingencies
Stockholders' equity (deficit):
  Common stock; no par value, 10,000 shares authorized,
     1,171 shares issued and outstanding....................          --           --
  Additional paid-in capital................................     172,625      172,625
  Accumulated deficit.......................................    (455,795)    (556,688)
  Notes receivable-related parties..........................     (43,020)     (43,020)
                                                              ----------   ----------
          Total stockholders' deficit.......................    (326,190)    (427,083)
                                                              ----------   ----------
          Total liabilities and stockholders' deficit.......  $1,022,046   $1,197,443
                                                              ==========   ==========
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-21
<PAGE>   274

                                  MOBEO, INC.

                            STATEMENTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                             FOR THE YEAR ENDED DECEMBER 31,
                                                           ------------------------------------
                                                              1996         1997         1998
                                                           ----------   ----------   ----------
<S>                                                        <C>          <C>          <C>
Service revenue..........................................  $6,484,864   $7,088,993   $8,580,786
Cost of services.........................................   2,947,185    3,148,051    3,040,743
                                                           ----------   ----------   ----------
Gross profit.............................................   3,537,679    3,940,942    5,540,043
                                                           ----------   ----------   ----------
Selling, general and administrative expenses:
  Sales and marketing....................................   1,641,502    1,812,696    2,302,360
  General and administrative.............................   1,149,218    1,937,829    2,706,544
  Research and development...............................      94,609      174,867      496,570
  Depreciation and amortization..........................     355,276      464,419      112,903
                                                           ----------   ----------   ----------
                                                            3,240,605    4,389,811    5,618,377
                                                           ----------   ----------   ----------
Other expense (income):
  Interest expense (income)..............................          --        2,628       (4,969)
  Loss on disposal of assets.............................          --      148,000       14,778
                                                           ----------   ----------   ----------
          Total other expenses (income)..................          --      150,628        9,809
                                                           ----------   ----------   ----------
Income (loss) before income taxes........................     297,074     (599,497)     (88,143)
Provision for (benefit from) income taxes................     120,150     (211,841)      12,750
                                                           ----------   ----------   ----------
Net income (loss)........................................  $  176,924   $ (387,656)  $ (100,893)
                                                           ==========   ==========   ==========
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-22
<PAGE>   275

                                  MOBEO, INC.

            STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT)

<TABLE>
<CAPTION>
                                                                                            NOTES
                                                               ADDITIONAL                 RECEIVABLE
                                                                PAID-IN     ACCUMULATED    RELATED
                                             SHARES   AMOUNT    CAPITAL       DEFICIT      PARTIES       TOTAL
                                             ------   ------   ----------   -----------   ----------   ---------
<S>                                          <C>      <C>      <C>          <C>           <C>          <C>
Balance at December 31, 1995...............  1,171     $--      $172,625     $(245,063)   $      --    $ (72,438)
  Issuance of notes receivable-related
    parties................................     --      --            --            --     (171,250)    (171,250)
  Net income...............................     --      --            --       176,924           --      176,924
                                             -----     ---      --------     ---------    ---------    ---------
Balance at December 31, 1996...............  1,171     $--      $172,625     $ (68,139)   $(171,250)   $ (66,764)
  Issuance of notes receivable-related
    parties................................     --      --            --            --      (65,603)     (65,603)
  Collections on notes receivable-related
    parties................................     --      --            --            --       71,250       71,250
  Allowance for notes receivable-related
    parties................................     --      --            --            --      122,583      122,583
  Net loss.................................     --      --            --      (387,656)          --     (387,656)
                                             -----     ---      --------     ---------    ---------    ---------
Balance at December 31, 1997...............  1,171      --       172,625      (455,795)     (43,020)    (326,190)
  Net loss.................................     --      --            --      (100,893)          --     (100,893)
                                             -----     ---      --------     ---------    ---------    ---------
Balance at December 31, 1998...............  1,171     $--      $172,625     $(556,688)   $ (43,020)   $(427,083)
                                             -----     ---      --------     ---------    ---------    ---------
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-23
<PAGE>   276

                                  MOBEO, INC.

                            STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                               FOR THE YEAR ENDED DECEMBER 31,
                                                              ---------------------------------
                                                                1996        1997        1998
                                                              ---------   ---------   ---------
<S>                                                           <C>         <C>         <C>
Cash flows from operating activities:
  Net income (loss).........................................  $ 176,924   $(387,656)  $(100,893)
  Adjustments to reconcile net income (loss) to net cash
    provided by operating activities:
    Bad debt expense........................................     23,976      62,956      51,620
    Deferred income taxes...................................     62,200    (211,841)     12,750
    Depreciation and amortization...........................    355,276     464,419     112,903
    Loss on disposal of assets..............................     57,472     148,009      14,778
    Allowance for notes receivable-related parties..........         --     122,583          --
    Changes in assets and liabilities:
       Accounts receivable..................................     74,989    (181,580)    (66,895)
       Income tax refund receivable.........................      6,414     (16,259)         --
       Restricted cash......................................     15,000          --          --
       Deposits, prepaid expenses and other.................     24,353     (30,990)      9,174
       Accounts payable and accrued expenses................    (66,407)    179,434     255,499
       Income tax payable...................................    (60,940)    (49,560)         --
       Deferred revenue.....................................   (127,115)      4,114      32,950
                                                              ---------   ---------   ---------
         Net cash provided by operating activities..........    542,142     103,629     321,886
                                                              ---------   ---------   ---------
Cash flows from investing activities:
  Purchase of property and equipment........................   (347,526)    (68,558)   (210,804)
  Payments to acquire patent................................         --          --     (30,456)
  Advances of notes receivable-related parties..............   (171,250)    (78,103)         --
  Collections on notes receivable-related parties...........         --      83,750          --
                                                              ---------   ---------   ---------
         Net cash used in investing activities..............   (518,776)    (62,911)   (241,260)
                                                              ---------   ---------   ---------
Cash flows from financing activities:
  Principal payments on capital leases......................    (42,268)    (48,414)    (12,159)
                                                              ---------   ---------   ---------
         Net cash used in financing activities..............    (42,268)    (48,414)    (12,159)
                                                              ---------   ---------   ---------
Net increase (decrease) in cash and cash equivalents........    (18,902)     (7,696)     68,467
Cash and cash equivalents at beginning of the year..........    152,044     133,142     125,446
                                                              ---------   ---------   ---------
Cash and cash equivalents at end of the year................  $ 133,142   $ 125,446   $ 193,913
                                                              =========   =========   =========
Supplemental disclosure of cash flow information:
  Cash paid for interest....................................  $  20,360   $  13,428   $   1,378
                                                              =========   =========   =========
  Cash paid for income taxes................................  $ 112,476   $  65,819   $      --
                                                              =========   =========   =========
  Supplemental disclosure of non-cash investing and
    financing activities:
    Allowance for notes receivable-related parties..........  $      --   $ 122,583   $      --
                                                              =========   =========   =========
</TABLE>

   The accompanying notes are an integral part of these financial statements

                                      F-24
<PAGE>   277

                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

1. ORGANIZATION

     DocuPro, Inc. was incorporated in the District of Columbia and commenced
operations in January 1989. In June 1998, DocuPro reincorporated in the state of
Delaware and in September 1998 changed its name to Mobeo, Inc. (the Company).
The Company is an electronic publisher specializing in providing financial
information over wireless networks. The Company's F/X Alert(R) service provides
major banks and financial institutions with continuous pricing and news
headlines of foreign exchange, government securities, and commodity markets on a
palm sized data terminal. The Company's PocketFutures(R) product provides the
individual futures trader with continuous pricing and news headlines of future
markets. Subsequent to December 31, 1998, the Company launched the Mobeo1.0(R)
product, designed for the individual equities trader.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

  Use of estimates

     The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenue and expenses during the reporting
period. Actual results could differ from those estimates.

  Cash and cash equivalents

     All highly liquid instruments with original maturities of three months or
less are considered to be cash equivalents. The Company invests its cash
balances in repurchase accounts with a large financial institution.

  Revenue recognition

     The Company enters into one year service contracts for providing financial
information over wireless networks. For substantially all its customers, the
Company bills on a monthly cycle and recognizes revenue monthly. Certain of the
Company's customers are billed in advance annually with revenue deferred and
recognized on a monthly basis over the life of the agreement. Non-refundable
activation fees are billed and recognized at the time of initial subscription.

  Concentration of credit risk

     Financial instruments that potentially subject the Company to
concentrations of credit risk consist principally of cash and cash equivalents
and accounts receivable. The Company maintains its cash and cash equivalents in
bank accounts which, at times, may exceed federally insured limits. The Company
has not experienced any losses in such bank accounts. The Company believes it is
not exposed to any significant credit risk on cash and cash equivalents. The
Company regularly monitors all outstanding accounts receivable balances to
assess collectibility. Accounts receivable as of December 31, 1997 and 1998, are
net of an allowance for doubtful accounts of $30,000 and $32,700, respectively.
The accounts receivable, which are not collateralized, are due mainly from banks
and financial institutions.

     Although the Company has sales on a national basis, 75% of their revenue
were derived in the New York City area. No individual accounts receivable were
greater than 10% of total accounts receivable as of December 31, 1997 and 1998.

                                      F-25
<PAGE>   278
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

  Property and equipment

     Property and equipment are recorded at cost. Property and equipment under
capital leases are recorded at the lower of their fair market value or the
present value of future minimum lease payments determined at the inception of
the lease.

     Amortization of leasehold improvements is recorded on a straight-line basis
over the shorter of the estimated useful life of the improvement or the term of
the lease. Amortization of property and equipment under capital leases is
recorded on a straight-line basis over the lease term. Property and equipment
under capital leases for which title passes to the Company at the conclusion of
the lease term is amortized on a straight line basis over the estimated useful
life of the related asset. Depreciation of other property and equipment is
recorded on a straight-line basis over expected useful lives of 3 to 10 years.

     When property and equipment is retired or otherwise disposed, the related
cost and accumulated depreciation are removed from the accounts and any
resulting gain or loss is reflected in income. Costs associated with repairs and
maintenance are expensed as incurred.

  Patents

     The cost of acquiring patents was approximately $30,000 as of December 31,
1998. Upon approval, the patents are to be amortized on a straight-line basis
over their estimated economic life, which is less than the statutory life of the
patents.

  Income taxes

     The Company accounts for income taxes in accordance with the liability
method. Deferred tax assets and liabilities are recognized for tax consequences
in future years for differences between financial reporting and tax bases of
assets and liabilities and are measured using the enacted tax rates and laws
that will be in effect when the differences are expected to reverse. The
provision for income taxes includes the current tax provision and the change
during the year in the net deferred tax liability or asset. A valuation
allowance is provided to reduce the deferred tax asset to a level which, more
likely than not, will be realized.

  Recent accounting pronouncements

     In June 1999, the FASB issued SFAS No. 137, Accounting for Derivative
Instruments and Hedging Activities-Deferral of the Effective Date of FASB No.
133 an amendment of FASB Statement No. 133, which defers the effective date of
SFAS No. 133 to all fiscal quarters of all fiscal years beginning after June 15,
2000. The Company will adopt SFAS No. 133 for the year ending December 31, 2000.
SFAS No. 133 requires that all derivative instruments be recorded on the balance
sheet at their fair value. Changes in the fair value of derivatives are recorded
each period in current earnings or other comprehensive income, depending on
whether a derivative is designated as part of a hedge transaction and, if it is,
the type of hedge transaction. Currently, the Company does not utilize
derivative instruments, therefore the adoption of SFAS No. 133 is not expected
to have a significant effect on the Company's results of operations or its
financial position.

  Reclassifications

     Certain amounts in the 1997 financial statements have been reclassified to
conform with the 1998 presentation.

                                      F-26
<PAGE>   279
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

3. PROPERTY AND EQUIPMENT

     Property and equipment consisted of the following:

<TABLE>
<CAPTION>
                                                                  DECEMBER 31,
                                                              ---------------------
                                                                1997        1998
                                                              ---------   ---------
<S>                                                           <C>         <C>
System hardware and software................................  $ 278,202   $ 196,038
Office furniture and equipment..............................    216,158     454,817
Leasehold improvements......................................     44,106      44,106
                                                              ---------   ---------
                                                                538,466     694,961
Less accumulated depreciation and amortization..............   (216,590)   (289,813)
                                                              ---------   ---------
                                                              $ 321,876   $ 405,148
                                                              =========   =========
</TABLE>

     During 1997, the Company leased certain office equipment under capital
leases. As of December 31, 1997, the cost of the office equipment related to
these capital leases was $44,035, and the accumulated amortization was $27,684.
These leases were fully amortized in 1998.

     During 1997, the Company reassessed the useful life of their pagers, which
are provided to customers upon activation of services at no fee. Since the
Company's service agreements are for a one-year period and subject to
cancellation, non-payment and non-return risk, management changed the estimated
useful life from three years to immediate expense recognition when the pagers
are acquired. As a result, the remaining net book value of pagers acquired prior
to 1997 of $228,000 was charged to depreciation expense for the year ended
December 31, 1997, while pagers purchased for the years ended December 31, 1997
and 1998 totaled $138,000 and $281,000, respectively.

     During 1997 and 1998, the Company disposed of certain system hardware and
software equipment with an original cost of $435,000 and $54,310, respectively,
and accumulated amortization of $287,000 and $35,675, respectively. The
resulting losses on disposals are included as a separate component on the
statement of operations.

4. INCOME TAXES

     The components of the provision for (benefit from) income taxes consisted
of the following:

<TABLE>
<CAPTION>
                                                                  YEAR ENDED
                                                                 DECEMBER 31,
                                                              -------------------
                                                                1997       1998
                                                              ---------   -------
<S>                                                           <C>         <C>
Current provision (benefit):
Federal.....................................................  $      --   $    --
State and local.............................................         --        --
                                                              ---------   -------
                                                                     --        --
                                                              ---------   -------
Deferred provision (benefit):
Federal.....................................................   (169,073)   10,200
State and local.............................................    (42,768)    2,550
                                                              ---------   -------
                                                               (211,841)   12,750
                                                              ---------   -------
Total provision for (benefit from) income taxes.............  $(211,841)  $12,750
                                                              =========   =======
</TABLE>

                                      F-27
<PAGE>   280
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

     Deferred income taxes reflect the net tax effects of temporary differences
between the carrying amounts of assets and liabilities for financial reporting
purposes and the amounts used for income tax purposes. Components of the
Company's net deferred tax assets and liabilities are as follows:

<TABLE>
<CAPTION>
                                                                 DECEMBER 31,
                                                              -------------------
                                                                1997       1998
                                                              --------   --------
<S>                                                           <C>        <C>
Current deferred tax assets
Allowance for doubtful accounts.............................  $ 64,848   $ 65,995
Deferred revenue............................................    30,264     36,611
Other.......................................................    10,714      3,163
Net operating loss carryback................................    36,539     80,780
                                                              --------   --------
Total current deferred tax assets...........................  $142,365   $186,549
                                                              --------   --------
Noncurrent deferred tax assets
Accumulated depreciation....................................    71,476     14,542
                                                              --------   --------
Total noncurrent deferred tax assets........................    71,476     14,542
                                                              --------   --------
Total deferred tax assets...................................  $213,841   $201,091
                                                              ========   ========
</TABLE>

     The change in the deferred tax assets in 1998 primarily represents the
effect of changes in the amounts of temporary differences. The Company's 1998
provision for income taxes differs from the provision that would have resulted
from applying the federal statutory rates to net loss before taxes due to
permanent differences primarily attributable to deductible business meals and
entertainment and other permanent differences of 48%. The Company believes it is
more likely than not to realize the net deferred tax asset and accordingly no
valuation allowance has been provided as of December 31, 1997 and 1998. This
conclusion is based on, (i) the Company's ability to carryback net operating
losses to offset taxable income from previous years and (ii) the Company's
expected future profitability.

5. PROFIT SHARING AND 401(k) PLANS

     The Company has a discretionary profit sharing plan and a self-directed
401(k) plan which cover all employees employed more than six months. Employees
become fully vested after three years of service. Employer contributions to the
profit sharing plan were $102,172 and $94,664 and contributions to the 401(k)
plan were $44,040 and $60,490 for the years ended December 31, 1997 and 1998,
respectively.

6. STOCK-BASED COMPENSATION

     On April 30, 1998, the Company adopted the Omnibus Stock Option Plan (the
Plan), under which incentive stock options, non-qualified stock options, stock
appreciation rights, restricted or unrestricted stock awards, phantom stock,
performance awards or any combination thereof may be granted to the Company's
employees and certain other persons in accordance with the Plan. The Board of
Directors, which administers the Plan, determines the number of options granted,
the vesting period and the exercise price. The Board of Directors may terminate
the Plan at any time. Options granted under the Plan generally vest over a four
year period and expire ten years after the date of grant. Prior to the common
stock becoming publicly traded, the Company retains the right of first offer to
buy the employees' shares at the offer price. At December 31, 1998, 48 shares
were reserved for issuance under the Plan.

                                      F-28
<PAGE>   281
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

     As of December 31, 1998, a total of 35 incentive stock options
respectively, had been granted to employees, at an exercise price of $3,250 per
share. The exercise price was established by the Board of Directors.

<TABLE>
<CAPTION>
                                                                                 WEIGHTED
                                                            INCENTIVE            AVERAGE
                                                              STOCK              EXERCISE
                                                             OPTIONS    PRICE     PRICE
                                                            ---------   ------   --------
<S>                                                         <C>         <C>      <C>
Options outstanding at December 31, 1997..................      --          --        --
Options granted...........................................      35      $3,250    $3,250
Options exercised.........................................      --          --
Options canceled..........................................      --          --        --
                                                               ---      ------    ------
Options outstanding at December 31, 1998..................      35      $3,250    $3,250
                                                               ---      ------    ------
Options granted...........................................      10      $3,250    $3,250
Options exercised.........................................      --          --
Options canceled..........................................      --          --        --
                                                               ---      ------    ------
Options outstanding at June 30, 1999 (unaudited)..........      45      $3,250    $3,250
                                                               ===      ======    ======
</TABLE>

     At December 31, 1998 no options were exercisable. The weighted-average fair
value of options granted during the year ended December 31, 1998.

     The Company measures compensation expense for its employee stock-based
compensation using the intrinsic value method and provides pro forma disclosures
of net loss as if the fair value method had been applied in measuring
compensation expense. Under the intrinsic value method of accounting for stock-
based compensation, when the exercise price of options granted to employees is
less than the fair value of the underlying stock on the date of grant,
compensation expense is to be recognized over the applicable vesting period. No
options granted through December 31, 1998 were less than fair value of the
underlying stock. Had the fair value method been applied, the Company's net loss
at December 31, 1998 would have been increased to the pro forma amounts
indicated below:

<TABLE>
<CAPTION>
                                                              DECEMBER 31,
                                                                  1998
                                                              ------------
<S>                                                           <C>
Net loss as reported........................................   $(100,893)
Pro forma net loss..........................................   $(103,313)
</TABLE>

     The fair value of each option is estimated on the date of grant using the
Black-Scholes option pricing model with the following weighted-average
assumptions used for grants during the year ended December 31, 1998: dividend
yield of 0%, expected volatility of 0%, risk-free interest rate of 5.07% and
expected term of 9 years.

     As of December 31, 1998, the weighted average remaining contractual life of
the options is 9.7 years.

7. COMMITMENTS AND CONTINGENCIES

  Data services and royalty arrangement

     In January 1995, the Company entered into a multi-year distribution
agreement with a provider of financial information for transmission to the
Company's customers. During 1998, the Company entered into two additional
multi-year agreements with new suppliers. Under these agreements, the Company
pays a monthly royalty to the data suppliers based on the number of wireless
units receiving data. Included in accounts payable at December 31, 1997 and 1998
and, respectively, related to purchases of financial information for
transmission to customers.

                                      F-29
<PAGE>   282
                                  MOBEO, INC.
                         NOTES TO FINANCIAL STATEMENTS

  Paging services

     In April 1994, the Company entered into a multi-year nonexclusive national
reseller agreement with a wireless messaging service provider. During 1998, the
Company entered into two additional multi-year nonexclusive national reseller
agreements with new suppliers. Under the terms of these agreements, the Company
is purchasing paging services from these providers for the purpose of marketing
and reselling such services to end users.

  Vulnerabilities due to certain concentrations

     The Company obtains all of its data from three sources and resells
primarily through one wireless messaging provider. Although there are a limited
number of data sources and messaging service providers, management believes that
they could obtain such services on terms comparable to the Company's existing
agreements. A change in suppliers, however, could cause delays in service, which
would adversely affect the Company's financial position, results of operations
and cash flows.

  Leases

     The Company leases office space in Bethesda, Maryland for its corporate
headquarters under an agreement which expires in December 1999. In addition, the
Company maintains facilities in New York, N.Y., under an agreement which expires
in 1999. The lease agreement for its corporate headquarters contains provisions
allowing free rent periods and periodic rate increases during the lease terms.
The Company recognizes rent expense under operating leases ratably over the
lease terms. As of December 31, 1997 and 1998, the Company had $13,000 and
$7,000, respectively, recorded as deferred rent included in accrued expenses.
Total rent expense was $238,783 and $239,936 for the years ended December 31,
1997 and 1998, respectively.

     In addition to office space, the Company leases an automobile under a 36
month operating lease, which expires in 1999.

     Future minimum lease payments under non-cancelable operating leases are as
follows:

<TABLE>
<S>                                                 <C>
1999..............................................  $201,695
</TABLE>

8. RELATED PARTY TRANSACTIONS

     In 1996, the Company advanced $171,250 to certain employees and
shareholders under notes receivable arrangements. During 1997, the Company
advanced an additional $78,103 under these arrangements, and received $83,750 in
collections on the notes receivables. There is no planned settlement of the
notes receivable balance in the foreseeable future, therefore the Company has
classified the amounts as a component of stockholders' equity (deficit). Under
these arrangements, the Company provided an allowance for doubtful accounts of
$122,583 to reflect the net realizable value of the notes at December 31, 1997
and 1998, respectively.

                                      F-30
<PAGE>   283

                          INDEPENDENT AUDITORS' REPORT

The Board of Directors and Stockholders
Riverbed Technologies, Inc.

     We have audited the accompanying balance sheets of Riverbed Technologies,
Inc. (the Company) as of December 31, 1998 and 1999, and the related statements
of operations, stockholders' equity (deficit), and cash flows for the period
from October 21, 1998 (date of inception) to December 31, 1998 and for the year
ended December 31, 1999. These financial statements are the responsibility of
the Company's management. Our responsibility is to express an opinion on these
financial statements based on our audits.

     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

     In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of Riverbed Technologies, Inc.
as of December 31, 1998 and 1999 and the results of its operations and its cash
flows for the period from October 21, 1998 (date of inception) to December 31,
1998 and for the year ended December 31, 1999, in conformity with generally
accepted accounting principles.

                                          KPMG LLP

McLean, Virginia
February 15, 2000

                                      F-31
<PAGE>   284

                          RIVERBED TECHNOLOGIES, INC.

                                 BALANCE SHEETS

<TABLE>
<CAPTION>
                                                                   DECEMBER 31,
                                                              -----------------------
                                                                1998         1999
                                                              --------    -----------
<S>                                                           <C>         <C>
                                       ASSETS
Current assets:
  Cash and cash equivalents.................................  $     --    $ 5,340,801
  Short-term investments....................................        --      3,936,542
  Accounts receivable.......................................    21,883        619,071
  Prepaids and other........................................        --        428,855
                                                              --------    -----------
          Total current assets..............................    21,883     10,325,269
Property and equipment, net.................................    48,161        718,075
                                                              --------    -----------
          Total assets......................................  $ 70,044    $11,043,344
                                                              ========    ===========
                     LIABILITIES, REDEEMABLE PREFERRED STOCK AND
                           STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable..........................................  $ 46,789    $   637,378
  Accrued expenses..........................................        --        497,135
  Deferred revenues.........................................     3,000         68,510
  Advance from stockholder..................................    81,834             --
  Note payable -- current portion...........................        --        120,578
                                                              --------    -----------
  Total current liabilities.................................   131,623      1,323,601
                                                              --------    -----------
Long-term liabilities:
  Note payable -- less current portion......................        --        241,155
                                                              --------    -----------
          Total liabilities.................................   131,623      1,564,756
                                                              --------    -----------
Series A preferred stock, convertible, $0.01 par value, zero
  and 3,500,000 shares authorized, issued and outstanding at
  December 31, 1998 and 1999, respectively (liquidation
  value $3,829,863).........................................        --      3,785,531
Series B preferred stock, convertible, $0.01 par value, zero
  and 4,145,211 shares authorized, issued and outstanding at
  December 31, 1998 and 1999, respectively (liquidation
  value $12,053,001)........................................        --     11,985,989
Stockholders' equity (deficit):
  Common stock, $0.01 par value, 100,000 and 14,354,789
     shares authorized at December 31, 1998 and 1999,
     respectively; 100,000 and 2,887,793 shares issued and
     outstanding at December 31, 1998 and 1999,
     respectively...........................................     1,000         28,878
  Additional paid-in-capital................................    (1,000)       561,033
  Accumulated deficit.......................................   (61,579)    (6,882,843)
                                                              --------    -----------
          Total stockholders' equity (deficit)..............   (61,579)    (6,292,932)
                                                              --------    -----------
  Commitments and contingencies
          Total liabilities, redeemable preferred stock and
            stockholders' equity (deficit)..................  $ 70,044    $11,043,344
                                                              ========    ===========
</TABLE>

                See accompanying notes to financial statements.
                                      F-32
<PAGE>   285

                          RIVERBED TECHNOLOGIES, INC.

                            STATEMENTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                                PERIOD FROM
                                                              OCTOBER 21, 1998
                                                           (DATE OF INCEPTION) TO       YEAR ENDED
                                                             DECEMBER 31, 1998       DECEMBER 31, 1999
                                                           ----------------------    -----------------
<S>                                                        <C>                       <C>
Software license revenue.................................         $     --              $   757,899
Maintenance, consulting and support revenue..............               --                  169,186
                                                                  --------              -----------
          Total revenue..................................               --                  927,085
Cost of software revenue.................................               --                  221,101
Cost of maintenance, consulting and support revenue......               --                  506,383
                                                                  --------              -----------
          Total cost of revenue..........................               --                  727,484
                                                                  --------              -----------
Gross profit.............................................               --                  199,601
Operating expenses:
Sales and marketing......................................           38,115                2,865,470
Research and development.................................           10,091                2,050,778
General and administrative...............................           13,373                1,055,071
Stock option expense.....................................               --                1,200,294
                                                                  --------              -----------
                                                                    61,579                7,171,613
                                                                  --------              -----------
          Operating loss.................................          (61,579)              (6,972,012)
Interest income (expense), net...........................               --                  150,748
                                                                  --------              -----------
Loss before income taxes.................................          (61,579)              (6,821,264)
Income taxes.............................................               --                       --
                                                                  --------              -----------
Net loss.................................................         $(61,579)             $(6,821,264)
Preferred stock dividend requirements....................               --                 (628,376)
                                                                  --------              -----------
Net loss available to common stockholders................         $(61,579)             $(7,449,640)
                                                                  ========              ===========
</TABLE>

                See accompanying notes to financial statements.
                                      F-33
<PAGE>   286

                          RIVERBED TECHNOLOGIES, INC.

                  STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT)

<TABLE>
<CAPTION>
                                    COMMON STOCK        ADDITIONAL
                                --------------------     PAID-IN-     ACCUMULATED
                                 SHARES        PAR       CAPITAL        DEFICIT         TOTAL
                                ---------    -------    ----------    -----------    -----------
<S>                             <C>          <C>        <C>           <C>            <C>
Balance at inception, October
  21, 1998....................         --    $    --    $       --    $        --    $        --
  Shares issued at
     inception................    100,000      1,000        (1,000)            --             --
  Net loss....................         --         --            --        (61,579)       (61,579)
                                ---------    -------    ----------    -----------    -----------
Balance at December 31,
  1998........................    100,000      1,000        (1,000)       (61,579)       (61,579)
  Stock split.................  1,722,917     17,229       (17,229)            --             --
  Issuance of common shares...    984,376      9,844            --             --          9,844
  Exercise stock options......     80,500        805         7,344             --          8,149
  Stock option expense........         --         --     1,200,294             --      1,200,294
  Preferred stock dividend
     requirements.............         --         --      (628,376)            --       (628,376)
  Net loss....................         --         --            --     (6,821,264)    (6,821,264)
                                ---------    -------    ----------    -----------    -----------
Balance at December 31,
  1999........................  2,887,793    $28,878    $  561,033    $(6,882,843)   $(6,292,932)
                                =========    =======    ==========    ===========    ===========
</TABLE>

                See accompanying notes to financial statements.
                                      F-34
<PAGE>   287

                          RIVERBED TECHNOLOGIES, INC.

                            STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                                PERIOD FROM
                                                              OCTOBER 21, 1998
                                                           (DATE OF INCEPTION) TO       YEAR ENDED
                                                             DECEMBER 31, 1998       DECEMBER 31, 1999
                                                           ----------------------    -----------------
<S>                                                        <C>                       <C>
Cash flow from operating activities:
  Net loss...............................................         $(61,579)             $(6,821,264)
  Adjustments to reconcile net loss to net cash used in
     operating activities
     Stock option expense................................               --                1,200,294
     Depreciation and amortization.......................               --                   97,050
     Changes in operating assets and liabilities:
       Increase in accounts receivable...................          (21,883)                (597,188)
       Increase in prepaids and other current assets.....               --                 (428,855)
       Increase in accounts payable and accrued
          expenses.......................................           46,789                1,087,724
       Increase in deferred revenue......................            3,000                   65,510
                                                                  --------              -----------
Net cash used in operating activities....................          (33,673)              (5,396,729)
                                                                  --------              -----------
Cash flows from investing activities:
     Purchases of property and equipment.................          (48,161)                (766,964)
     Purchase of short-term investments..................               --               (3,936,542)
                                                                  --------              -----------
  Net cash used in investing activities..................          (48,161)              (4,703,506)
                                                                  --------              -----------
Cash flows from financing activities:
     Advance (repayment) from stockholder................           81,834                  (81,834)
     Proceeds from the issuance of common stock and
       exercise of stock options.........................               --                   17,993
     Proceeds from the issuance of preferred stock, net
       of issuance costs.................................               --               15,143,144
     Proceeds from line of credit........................               --                  250,000
     Repayment on line of credit.........................               --                 (250,000)
     Proceeds from note payable..........................               --                  361,733
                                                                  --------              -----------
Net cash provided by financing activities................           81,834               15,441,036
Net increase in cash and cash equivalents................               --                5,340,801
Cash and cash equivalents, beginning of period...........               --                       --
                                                                  --------              -----------
Cash and cash equivalents, end of period.................         $     --              $ 5,340,801
                                                                  ========              ===========
Supplemental disclosure of cash flow information:
  Interest...............................................         $     --              $     4,355
  Income taxes...........................................         $     --              $        --
</TABLE>

                See accompanying notes to financial statements.
                                      F-35
<PAGE>   288

                          RIVERBED TECHNOLOGIES, INC.

                         NOTES TO FINANCIAL STATEMENTS

(1) ORGANIZATION AND DESCRIPTION OF BUSINESS

     Riverbed Technologies, Inc. (the "Company"), a Delaware corporation, was
formed on October 21, 1998 and is based in Vienna, Virginia.

     The Company designs, develops, sells and supports synchronization and
management software that enables handheld devices to be used as a natural
extension of the enterprise and systems enabling people to use wireless handheld
devices for data communications and transactions. The Company operates in a
highly competitive environment subject to rapid technological change and
emergence of new technology. Although management believes its services are
transferable to emerging technologies, rapid changes in technology could have an
adverse financial impact on the Company.

     The Company expects to expand its operations through continued capital
investment in new systems and services. The Company is not currently generating
sufficient cash flows from operations to support its current operating and
capital requirements. The Company has and will continue to be dependent upon its
stockholders and other financing sources to fund these requirements.

(2) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

  (a) Revenue Recognition

     Revenues are generated from licensing software and providing services,
including maintenance and technical support, training and consulting.

     In October 1997, the American Institute of Certified Public Accountants
("AICPA") issued Statement of Position ("SOP") No. 97-2, Software Revenue
Recognition. Subsequently, in March 1998 and December 1998, the AICPA issued SOP
98-4 and SOP 98-9, respectively, which defer until the Company's fiscal year
beginning January 1, 2000, the application of several paragraphs and examples in
SOP 97-2 that limit the definition of vendor specific objective evidence
("VSOE") for determining fair value of various elements in a multiple element
arrangement. The provisions of SOP 97-2 have been applied to transactions
entered into from the inception (October 21, 1998) of the Company. Management of
the Company does not believe that the adoption of the remaining portions of SOP
97-2, which were deferred by SOP 98-4 and SOP 98-9, will have a material impact
on the Company's financial statements.

     Software revenue consists of fees for licenses of the Company's software
products. The Company recognizes the revenue when the license agreement is
signed, the license fee is fixed and determinable, delivery of the software has
occurred, and collectibility of the fee is considered probable.

     Services revenue consists of maintenance and technical support, training
and consulting. Revenues from maintenance and technical support, which consists
of unspecified when-and-if-available product updates and customer telephone
support services, are recognized ratably over the term of the service period.
Other services revenues are recognized as the related services is provided.

  (b) Cost of Revenues

     The cost of software license revenues consists primarily of third party
royalties. The cost of maintenance, consulting and support revenue consists
primarily of personnel-related costs.

  (c) Software Development Costs

     Software development costs are accounted for in accordance with Statement
of Financial Accounting Standards ("SFAS") No. 86, Accounting for the Costs of
Computer Software to be Sold, Leased or Otherwise Marketed (the "Standard").
Under the Standard, capitalization of software development costs begins upon the
establishment of technological feasibility, subject to net realizable value
considerations. To

                                      F-36
<PAGE>   289
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

date, the period between achieving technological feasibility and the general
availability of such software has been short; therefore, software development
costs qualifying for capitalization have been immaterial. Accordingly, the
Company has not capitalized any software development costs and has charged all
such costs to research and development expense. Research and development costs
are expensed as incurred.

  (d) Advertising Expense

     Advertising costs are expensed as incurred. Advertising expense was $0 and
$343,000 for the period from October 21, 1998 (date of inception) to December
31, 1998 and for the year ended December 31, 1999, respectively.

  (e) Income Taxes

     The Company recognizes income taxes using the asset and liability method,
in accordance with Statement of Financial Accounting Standards ("SFAS") No. 109.
Under the asset and liability method, deferred tax assets and liabilities are
recognized for the future tax consequences attributable to differences between
the financial statement carrying amounts of existing assets and liabilities and
their respective tax bases. Deferred tax assets and liabilities are measured
using enacted tax rates expected to apply to taxable income in the years in
which those temporary differences are expected to be recovered or settled. The
effect of a tax rate change on deferred tax assets and liabilities is recognized
in income in the period that includes the enactment date.

  (f) Cash and Cash Equivalents

     Cash equivalents include all highly liquid investments with original
maturities of three months or less. Cash equivalents include approximately
$3,508,000 in money market accounts as of December 31, 1999.

  (g) Short-term Investments

     Short-term investments consist of highly liquid investments with original
maturities greater than three months and less than one year. Short-term
investments consisted of U.S. Treasury securities. Short-term investments are
recorded at their amortized cost which approximates fair value as of December
31, 1999.

  (h) Concentration of Credit Risk

     Financial instruments that potentially subject the Company to credit risk
consist of accounts receivable. The Company extends credit to its customers on
an unsecured basis in the normal course of business.

     For the year ended December 31, 1999, the Company derived approximately 60
percent of its revenue from three customers. As of December 31, 1999,
approximately 88 percent of the accounts receivable balance was due from four
customers.

  (i) Use of Estimates

     The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and the
disclosure of contingent assets and liabilities at the dates of the financial
statements and reported amounts of revenues and expenses during the reporting
period. Actual results could differ from those estimates.

                                      F-37
<PAGE>   290
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

  (j) Fair Value of Financial Instruments

     The carrying of the Company's financial instruments, including cash and
cash equivalents, accounts receivable, accounts payable, accrued expenses and
notes payable approximate their fair value because of the short duration of the
instruments.

  (k) Property and Equipment

     Property and equipment are stated at cost. Depreciation is calculated using
the straight-line method over the estimated useful lives of the assets, which
range from three to five years. The costs of leasehold improvements are
amortized using the straight-line method over the shorter of the lease term or
the estimated useful life of the asset.

  (l) Recovery of Long-Lived Assets

     The Company's policy is to review its long-lived assets for impairment
whenever events or changes in circumstances indicate that the carrying amount
may not be recoverable. The Company recognizes an impairment loss when the sum
of the expected future undiscounted cash flows is less than the carrying amount
of the asset. The measurement of the impairment losses to be recognized is based
upon the difference between the fair value and the carrying amount of the
assets.

  (m) Stock Compensation

     The Company accounts for stock-based employee compensation arrangements in
accordance with the provisions of Accounting Principles Board ("APB") No. 25,
"Accounting for Stock Issued to Employees," and complies with the disclosure
requirements of SFAS No. 123, "Accounting for Stock-Based Compensation." Under
APB No. 25, compensation cost, if any, is recognized over the respective vesting
period based on the difference, on the date of grant, between the fair value of
the Company's common stock and the exercise price. All stock-based awards to
non-employees are accounted for at their fair value in accordance with SFAS No.
123.

  (n) Other Comprehensive Loss

     The Company has adopted the provisions of SFAS No. 130, "Reporting
Comprehensive Income." SFAS No. 130 established standards for reporting
comprehensive income and its components in financial statements. Comprehensive
income, as defined, includes changes in equity of business enterprise during a
period from transactions and other events and circumstances from non-owner
sources. Other comprehensive income refers to revenue, expenses, gains and
losses that under generally accepted accounting principles are included in
comprehensive income, but excluded from net income. The Company has had no
transactions of this nature since its inception.

  (o) Recent Accounting Pronouncements

     In June 1998, the Financial Accounting Standards Board ("FASB") issued SFAS
No. 133, "Accounting for Derivative Instruments and Hedging Activities." The new
standard establishes accounting and reporting standards for derivative
instruments, including certain derivative instruments embedded in other
contracts, and for hedging activities. This statement, as amended, is effective
for all fiscal quarters beginning after June 15, 2000. The Company does not
expect SFAS No. 133 to have a material affect on its financial position or
results of operations.

                                      F-38
<PAGE>   291
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

(3) CAPITALIZATION

     The Company's Certificate of Incorporation, as amended, authorizes the
Company to issue 14,354,789 shares of common stock. As of December 31, 1999, the
Company had reserved shares of common stock for future issuance as follows:

<TABLE>
<S>                                                           <C>
Conversion of Series A Preferred Stock......................  3,500,000
Conversion of Series B Preferred Stock......................  4,145,412
Exercise of stock options pursuant to stock option plan.....  2,484,376
</TABLE>

     On October 21, 1998, the Company was formed and initially capitalized when
Noblestar Systems Corporation ("NobleStar") contributed certain intangible
assets in exchange for all 100,000 shares of the Company's authorized common
stock. On January 16, 1999, the Company effected a stock split of 18.22917 to 1
of its common stock. On January 20, 1999, the Company granted 984,376 shares of
common stock to two of its founders. In connection with this grant the Company
recorded stock option expense of approximately $778,000.

(4) PREFERRED STOCK

     In January 1999, the Company issued 3,500,000 shares of Series A Preferred
Stock ("Series A") at a price of $1.00 per share. Total proceeds, net of
offering expenses, were approximately $3,442,000.

     In October 1999, the Company issued 4,145,211 shares of Series B Preferred
Stock ("Series B") at a price of $2.84 per share. Total proceeds, net of
offering expenses, were approximately $11,701,000.

  (a) Voting Rights and Protective Provisions

     The Series A and B stockholders may vote with the common stock as a single
class on all actions to be taken by the stockholders. The Series A and B
stockholders each are entitled to elect one member of the Board of Directors
provided that at least 10 percent of authorized preferred stock of each class is
then outstanding. Furthermore, as long as 10 percent of each class of preferred
stock is outstanding, approval by at least two-thirds of holders of then
outstanding shares of Series A and B is required for: (i) changing rights,
preferences or privileges of each class; and (ii) issuing any equity security
having a preference or parity with each class with respect to voting, dividends,
liquidation or redemption. Finally, as long as 10 percent of each class of
preferred stock of each class is outstanding, approval by at least fifty percent
of the holders of then outstanding shares of Series and A and B is required for:
(i) the sale of the Company or substantially all of its assets; (ii) increasing
the authorized number of shares of preferred stock or common stock; (iii)
amending the Company's charter or bylaws; (iv) materially changing the Company's
business; (v) approving an annual budget and executive compensation plan,
including expenses greater than $100,000; or (vi) increasing the number of
directors of the Company.

  (b) Dividends

     Series A and B stock accrues cumulative dividends at rate of 10 percent per
annum, whether or not the dividends are declared by the Board of Directors.
Unpaid and undeclared dividends on Series A and Series B was approximately
$330,000 and $280,000, respectively, as of December 31, 1999.

  (c) Liquidation

     In the event of any liquidation, dissolution, or winding up of the
Corporation, either voluntary or involuntary, the holders of Series A and B
stock shall be entitled to receive an amount equal to the original share price
paid plus any unpaid cumulative dividends, whether or not declared. The Series A
and

                                      F-39
<PAGE>   292
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

B stockholders may also participate on an equal basis with the common stock in
any remaining assets after accumulated dividend are paid.

  (d) Redemption

     Series A and B stock are redeemable after October 2003 upon notice to the
Company by at least 50 percent of the holders of the then outstanding stock. The
redemption price shall equal the liquidation amount and is payable in three
annual installments beginning on the redemption date.

  (e) Conversion

     Series A and B stock is convertible on a one-for-one basis into shares of
common stock at the option of the holder. Series A and B stock is automatically
converted into common stock in the event of an initial public offering in which
the aggregate proceeds are not less than $15,000,000 and the Company's pre-
offering valuation is at least $150,000,000.

(5) PROPERTY AND EQUIPMENT

     Property and equipment consists of the following:

<TABLE>
<CAPTION>
                                                                 DECEMBER 31,
                                                              -------------------
                                                               1998        1999
                                                              -------    --------
<S>                                                           <C>        <C>
Computer hardware...........................................  $48,161    $638,594
Computer software...........................................       --     158,375
Furniture and fixtures......................................       --      18,156
                                                              -------    --------
                                                               48,161     815,125
Less: Accumulated depreciation..............................       --      97,050
                                                              -------    --------
                                                              $48,161    $718,075
                                                              =======    ========
</TABLE>

(6) LINE OF CREDIT AND NOTES PAYABLE

     In August 1999, the Company entered into a two-tranche credit facility with
a bank for a maximum available credit of $2,000,000. The assets and intellectual
properties of the Company collateralize the facility.

     The first tranche is an equipment note payable not to exceed $500,000, of
which, approximately $362,000 was payable at December 31, 1999. Amounts
available under the equipment note payable are limited to the advance purchase
of certain equipment through June 30, 2000. At December 31, 1999, there was
approximately $138,000 available to the Company under the equipment financing.
Principal is payable in thirty-six equal installments plus interest commencing
in January 2000. Any amounts drawn down between January and June 2000, and the
related interest, are due in thirty-six equal installments commencing in July
2000. Interest accrues on the unpaid principal at 1.625% above the bank's prime
rate (10.125% at December 31, 1999).

     The second tranche is a revolving line of credit not to exceed $1,500,000.
Amounts available under the revolving line of credit are limited by certain
asset based formulas and at December 31, 1999, there was approximately $836,000
available to the Company. All outstanding principal and interest is due on
January 31, 2001, the termination date of the revolving line of credit. Interest
accrues on the unpaid principal at 1.25% above the bank's prime rate (9.75% at
December 31, 1999) and is payable monthly.

     Finally, as of December 31, 1999, an irrevocable standby letter of credit
for $100,000 was established in lieu of a deposit on the lease for the Company's
headquarters.
                                      F-40
<PAGE>   293
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

(7) EMPLOYEE BENEFIT PLANS

  Retirement Plan

     As of March 1, 1999, the Company adopted a 401(k) Retirement Plan (the
"Plan") covering substantially all its employees. Participants in the Plan may
elect to defer up to 15% of their compensation. The Company may make a
discretionary matching contribution. In 1999, the Company matched 50% of
employee contributions up to 6% of compensation. The amount recorded as expense
for the year ended December 31, 1999 was approximately $25,000.

  Stock Option Plan

     During 1999, the Board of Directors adopted the 1999 Stock Option Plan
("the Stock Plan"). The Company has reserved up to 2,484,376 shares for issuance
under the Stock Plan. All of the Company's employees, officers, directors,
consultants and advisors are eligible to be granted options under the Stock
Plan. The exercise price and duration of the option are determined by the Board
at the date of grant. The options generally vest ratably over a period of 4
years, and generally expire in 10 years.

     The following table summarizes option activity for the year ended December
31, 1999. No options were granted in 1998.

<TABLE>
<CAPTION>
                                                                      1999
                                                              ---------------------
                                                                           WEIGHTED
                                                                           AVERAGE
                                                                           EXERCISE
                                                               SHARES       PRICE
                                                              ---------    --------
<S>                                                           <C>          <C>
Outstanding at beginning of year............................         --     $  --
Granted.....................................................  1,823,641      0.60
Exercised...................................................    (80,500)     0.10
Cancelled...................................................   (113,996)     0.10
                                                              ---------     -----
Outstanding at year end.....................................  1,629,145      0.65
                                                              =========     =====
Options exercisable at year end.............................    324,252      0.35
                                                              =========     =====
Options available for future grant..........................    660,735
                                                              =========
</TABLE>

     The per share weighted-average fair value of the options granted during
1999 was $1.90. The fair value of each option grant is estimated on the date of
grant, using the Black-Scholes options-pricing model with the following
assumptions: expected option life of 5 years, volatility of zero, risk-free
interest rate of 6.0% and dividend yield of zero percent.

<TABLE>
<CAPTION>
                    OPTIONS OUTSTANDING              OPTIONS EXERCISABLE
           -------------------------------------   -----------------------
              NUMBER       WEIGHTED                   NUMBER
           OUTSTANDING      AVERAGE     WEIGHTED   EXERCISABLE    WEIGHTED
                AT         REMAINING    AVERAGE       AS OF       AVERAGE
EXERCISE   DECEMBER 31,   CONTRACTUAL   EXERCISE   DECEMBER 31,   EXERCISE
 PRICES        1999          LIFE        PRICE         1999        PRICE
- --------   ------------   -----------   --------   ------------   --------
<S>        <C>            <C>           <C>        <C>            <C>
 $0.10        396,545        2.85        $0.10       216,336       $0.10
 $0.30        284,100        3.60        $0.30            --          --
 $0.85        854,000        3.83        $0.85       107,916        0.85
 $2.27         94,500        3.88        $2.27            --          --
            ---------                                -------       -----
            1,629,145        3.48        $0.65       324,252       $0.35
            =========                                =======
</TABLE>

                                      F-41
<PAGE>   294
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

     The Company applies APB Opinion No. 25 and related interpretations in
accounting for its stock options. The Company recorded compensation expense of
approximately $422,000 relating to options granted in the year ended December
31, 1999, equal to the difference between the estimated fair market value of the
Company's common stock on the grant date and the exercise price of the options.
The expense will be recognized ratably over the vesting period of the options,
which is generally four years.

     SFAS No. 123 requires pro forma net income (loss) disclosures as if the
Company had accounted for its stock options granted under the fair value method
prescribed by that statement. Had the Company used the fair value methodology
for determining compensation expense, the following table presents the pro forma
net income (loss) that would have been recorded by the Company for the options
granted during the year ended December 31, 1999:

<TABLE>
<CAPTION>
                                                                          YEAR ENDED
                                                                         DECEMBER 31,
                                                                             1999,
                                                                     ---------------------
<S>                                                   <C>            <C>
Net loss............................................  As reported         $(6,821,264)
                                                      Proforma            $(6,863,264)
</TABLE>

     The effects of applying SFAS No. 123 in this pro forma disclosure are not
indicative of future amounts.

(8) INCOME TAXES

     No provision for federal or state income taxes has been recorded as the
Company incurred net operating losses for all periods presented. As of December
31, 1999, the Company had net operating loss carryforwards available to offset
future taxable income of approximately $5,755,000 which expire in 2019. The
actual income tax benefit differed from the income tax benefit which would be
computed based upon the statutory federal tax rates as a result of recording a
valuation allowance.

     The tax effected amounts of temporary differences as of December 31, 1998
and 1999 are as follows:

<TABLE>
<CAPTION>
                                                                   DECEMBER 31,
                                                            --------------------------
                                                               1998           1999
                                                            -----------    -----------
<S>                                                         <C>            <C>
Deferred tax assets:
Net operating loss carryforward...........................  $        --    $ 2,359,000
Start-up costs............................................       25,000         19,000
Accrued vacation..........................................           --         10,000
                                                            -----------    -----------
Total deferred tax assets.................................       25,000      2,388,000
Valuation allowance.......................................      (25,000)    (2,340,000)
                                                            -----------    -----------
Net deferred tax assets...................................           --         48,000
                                                            -----------    -----------
Deferred tax liabilities:
Depreciation and amortization.............................           --         48,000
                                                            -----------    -----------
Total deferred tax liabilities............................           --         48,000
                                                            -----------    -----------
Net deferred taxes........................................  $        --    $        --
                                                            ===========    ===========
</TABLE>

(9) LEASES

     In December 1999, the Company entered into a long-term, non-cancelable
operating lease for its headquarters. The Company also leases other facilities
and certain office equipment under short-term, non-

                                      F-42
<PAGE>   295
                          RIVERBED TECHNOLOGIES, INC.

                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)

cancelable operating leases. Future minimum lease payments under non-cancelable
operating leases are as follows:

<TABLE>
<CAPTION>
                                                               MINIMUM
                                                                LEASE
YEARS ENDING DECEMBER 31,                                      PAYMENTS
- -------------------------                                     ----------
<S>                                                           <C>
  2000......................................................  $  563,000
  2001......................................................     572,000
  2002......................................................     587,000
  2003......................................................      52,000
                                                              ----------
                                                              $1,774,000
                                                              ==========
</TABLE>

     Rent expense under operating leases was approximately $400 and $107,000,
for the period from October 21, 1998 (date of inception) to December 31, 1998
and the year ended December 31, 1999, respectively.

(10) RELATED PARTY TRANSACTIONS

     In 1998, the Company's operations were funded through non-interest bearing
advances made by Noblestar. As of December 31, 1998, approximately $82,000 was
due to Noblestar for such advances. These amounts were repaid in 1999.

(11) SUBSEQUENT EVENT

     On February 9, 2000, the Company entered into a definitive merger agreement
to be acquired by Aether Systems, Inc. for approximately 4,537,000 shares of
Aether's common stock, plus the issuance of options to acquire approximately
863,000 shares of Aether's common stock for replacement of existing options
issued to the Company's employees. The acquisition is subject to regulatory and
stockholder approval.

                                      F-43
<PAGE>   296

                         UNAUDITED PRO FORMA CONDENSED
                       CONSOLIDATED FINANCIAL INFORMATION

     The unaudited pro forma condensed consolidated financial information has
been prepared by Aether's management and gives effect to:

     (1) the acquisition of Mobeo, Inc. completed on September 28, 1999 and the
         acquisition of LocusOne Communications, Inc. completed on February 3,
         2000, which are collectively referred to in this "Unaudited Pro Forma
         Condensed Consolidated Financial Information" section as the "Completed
         Transactions", and

     (2) the pending acquisition of Riverbed Technologies, Inc. which is
         referred to in this "Unaudited Condensed Consolidated Pro Forma
         Financial Information" section as the "Pending Transaction".

     The pro forma condensed consolidated statement of operations for the year
ended December 31, 1999 has been prepared to give effect to the Mobeo, LocusOne
and Riverbed acquisitions as if they had occurred on January 1, 1999. The pro
forma as adjusted statement of operations gives effect to the Mobeo, LocusOne,
and Riverbed acquisitions plus the offering of convertible notes covered by this
prospectus and the application of the net proceeds. The pro forma as further
adjusted statement of operations also gives effect to the concurrent offering of
common stock and the application of the net proceeds. The pro forma condensed
consolidated balance sheet as of December 31, 1999 gives effect to the LocusOne
and Riverbed acquisitions as if they had occurred on December 31, 1999. The
acquisition of Mobeo, which occurred prior to December 31, 1999, is already
reflected in the Company's historical consolidated balance sheet as of December
31, 1999. The pro forma as adjusted balance sheet gives effect to the LocusOne
and Riverbed acquisitions plus the offering of convertible notes covered by this
prospectus and the application of the net proceeds. The pro forma as further
adjusted balance sheet also gives effect to the concurrent offering of common
stock and the application of the net proceeds.

     The pro forma adjustments, which are based upon available information and
certain assumptions that Aether believes are reasonable in the circumstances,
are applied to the historical financial statements of Aether, Mobeo, LocusOne
and Riverbed. The acquisitions are accounted for under the purchase method of
accounting. Aether's allocation of the purchase price is based upon the
estimated fair value of assets acquired and liabilities assumed in accordance
with Accounting Principles Board Opinion No. 16. The purchase price allocations
reflected in the accompanying unaudited pro forma condensed consolidated
financial statements may be different from the final allocation of the purchase
price and any such differences may be material.

     The accompanying unaudited pro forma condensed consolidated financial
information should be read in conjunction with the historical financial
statements and the notes thereto for Aether, Mobeo and Riverbed which are
included elsewhere in this prospectus. The unaudited pro forma condensed
consolidated financial information are provided for informational purposes only
and do not purport to represent what Aether's financial position or results of
operations would actually have been had the acquisitions occurred on such dates
or to project Aether's results of operations or financial position for any
future period.

                                      F-44
<PAGE>   297

                              AETHER SYSTEMS, INC.

            UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET

<TABLE>
<CAPTION>
                                                               AS OF DECEMBER 31, 1999
                                    -----------------------------------------------------------------------------
                                                                    AETHER AS
                                                    ADJUSTMENTS    ADJUSTED FOR    ADJUSTMENTS
                                     HISTORICAL    FOR COMPLETED    COMPLETED      FOR PENDING       PRO FORMA
                                       AETHER      TRANSACTIONS    TRANSACTION     TRANSACTION      CONSOLIDATED
                                    ------------   -------------   ------------   --------------   --------------
<S>                                 <C>            <C>             <C>            <C>              <C>
                                                     ASSETS
Current assets:
  Cash and cash equivalents.......  $ 78,541,792   $(21,163,853)   $ 57,377,939   $   (9,659,199)  $   47,718,740
  Short-term investments..........     2,091,962             --       2,091,962        3,936,542        6,028,504
  Trade accounts receivable,
    net...........................     1,002,845        256,423       1,259,268          619,071        1,878,339
  Inventory, net..................       688,494             --         688,494               --          688,494
  Prepaid expenses and other
    current assets................     4,994,965          6,573       5,001,538          428,855        5,430,393
                                    ------------   ------------    ------------   --------------   --------------
         Total current assets.....    87,320,058    (20,900,857)     66,419,201       (4,674,731)      61,744,470
Property and equipment, net.......     2,795,920        197,821       2,993,741          718,075        3,711,816
Intangible assets, net............    12,209,442     39,868,502      52,077,944    1,126,324,412    1,178,402,356
Other assets......................       208,698             --         208,698               --          208,698
                                    ------------   ------------    ------------   --------------   --------------
                                    $102,534,118   $ 19,165,466    $121,699,584   $1,122,367,756   $1,244,067,340
                                    ============   ============    ============   ==============   ==============
                                      LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable................  $  1,425,435   $     79,975    $  1,505,410   $      637,378   $    2,142,788
  Accrued expenses................     1,619,947             --       1,619,947          497,135        2,117,082
  Accrued employee compensation
    and benefits..................       971,110             --         971,110               --          971,110
  Deferred revenue................       175,193        110,469         285,662           68,510          354,172
  Notes payable current portion...                   18,975,022      18,975,022          120,578       19,095,600
                                    ------------   ------------    ------------   --------------   --------------
         Total current
           liabilities............     4,191,685     19,165,466      23,357,151        1,323,601       24,680,752
Notes payable-less current
  portion.........................            --             --              --          241,155          241,155
                                    ------------   ------------    ------------   --------------   --------------
                                       4,191,685     19,165,466      23,357,151        1,564,756       24,921,907
Stockholders' equity
  Preferred stock.................            --             --              --               --               --
  Common stock....................       271,543             --         271,543           45,373          316,916
  Additional paid-in-capital......   120,892,478             --     120,892,478    1,120,757,627    1,241,650,105
  Accumulated deficit.............   (22,613,640)            --     (22,613,640)              --      (22,613,640)
  Notes receivable from
    shareholder...................      (137,879)            --        (137,879)              --         (137,879)
  Unrealized loss on
    investments...................       (70,069)            --         (70,069)              --          (70,069)
                                    ------------   ------------    ------------   --------------   --------------
         Total stockholders'
           equity.................    98,342,433             --      98,342,433    1,120,803,000    1,219,145,433
                                    ------------   ------------    ------------   --------------   --------------
                                    $102,534,118   $ 19,165,466    $121,699,584   $1,122,367,756   $1,244,067,340
                                    ============   ============    ============   ==============   ==============
</TABLE>

                                      F-45
<PAGE>   298
                              AETHER SYSTEMS, INC.

    UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET -- (CONTINUED)

<TABLE>
<CAPTION>
                                                                        AS OF DECEMBER 31, 1999
                                       -----------------------------------------------------------------------------------------
                                                          PRO FORMA                            PRO FORMA            PRO FORMA
                                         PRO FORMA      DEBT OFFERING         PRO FORMA      STOCK OFFERING         AS FURTHER
                                        CONSOLIDATED     ADJUSTMENTS         AS ADJUSTED      ADJUSTMENTS            ADJUSTED
                                       --------------   -------------       --------------   --------------       --------------
<S>                                    <C>              <C>                 <C>              <C>                  <C>
                                                             ASSETS
Current assets:
  Cash and cash equivalents..........  $   47,718,740   $ 46,824,978(A)     $   94,543,718    $452,544,190(B)     $  547,087,908
  Short-term investments.............       6,028,504                            6,028,504                             6,028,504
  Trade accounts receivable, net.....       1,878,339                            1,878,339                             1,878,339
  Inventory, net.....................         688,494                              688,494                               688,494
  Prepaid expenses and other current
    assets...........................       5,430,393                            5,430,393                             5,430,393
                                       --------------   ------------        --------------    ------------        --------------
        Total current assets.........      61,744,470     46,824,978           108,569,448     452,544,190           561,113,638
Property and equipment, net..........       3,711,816                            3,711,816                             3,711,816
Intangible assets, net...............   1,178,402,356                        1,178,402,356                         1,178,402,356
Other assets.........................         208,698    134,200,000(A)        134,408,698              --           134,408,698
                                       --------------   ------------        --------------    ------------        --------------
                                       $1,244,067,340   $181,024,978        $1,425,092,318    $452,544,190        $1,877,636,508
                                       ==============   ============        ==============    ============        ==============
                                              LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable...................  $    2,142,788   $                   $    2,142,788    $                   $    2,142,788
  Accrued expenses...................       2,117,082                            2,117,082                             2,117,082
  Accrued employee compensation and
    benefits.........................         971,110                              971,110                               971,110
  Deferred revenue...................         354,172             --               354,172              --               354,172
  Notes payable......................      19,095,600    (18,975,022)(A)           120,578                               120,578
                                       --------------   ------------        --------------    ------------        --------------
        Total current liabilities....      24,680,752    (18,975,022)            5,705,730                             5,705,730
  Notes payable......................         241,155             --               241,155                               241,155
  Convertible subordinated notes
    payable..........................              --    200,000,000(A)        200,000,000              --           200,000,000
                                       --------------   ------------        --------------    ------------        --------------
                                           24,921,907    181,024,978           205,946,885              --           205,946,885
Stockholders' equity
  Preferred stock....................              --             --                    --              --                    --
                                                   --                                                                         --
  Common stock.......................         316,916                              316,916          24,913(B)            341,829
  Additional paid-in-capital.........   1,241,650,105                        1,241,650,105     452,519,277(B)      1,694,169,382
  Accumulated deficit................     (22,613,640)                         (22,613,640)                          (22,613,640)
  Notes receivable from
    shareholder......................        (137,879)                            (137,879)                             (137,879)
  Unrealized loss on investments.....         (70,069)                             (70,069)                              (70,069)
                                       --------------   ------------        --------------    ------------        --------------
        Total stockholders' equity...   1,219,145,433             --         1,219,145,433     452,544,190         1,671,689,623
                                       --------------   ------------        --------------    ------------        --------------
                                       $1,244,067,340   $181,024,978        $1,425,092,318    $452,544,190        $1,877,636,508
                                       ==============   ============        ==============    ============        ==============
</TABLE>

- ---------------
(A) Reflects the sale of an aggregate $200 million of -- % convertible
    subordinated notes due in 2005 in the offering, less underwriting discounts
    and commissions and offering expenses of $7.2 million recorded as deferred
    financing fees, the repayment of approximately $19 million of indebtedness
    incurred in connection with the LocusOne acquisition, the investment of $100
    million in the new company formed with Reuters, the investment of $17
    million in Metrocall, and the investment of $10 million in Inciscent.

(B) Reflects the sale of 2,346,219 shares of common stock in the concurrent
    offering, assuming an offering price of $203 per share, after deducting
    underwriting discounts and commissions and offering expenses and the
    exercise of options to purchase 145,000 shares by the selling stockholders.

                                      F-46
<PAGE>   299

                              AETHER SYSTEMS, INC.

            UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET
                     ADJUSTMENTS FOR COMPLETED TRANSACTIONS

<TABLE>
<CAPTION>
                                                             AS OF DECEMBER 31, 1999
                                                  ----------------------------------------------
                                                                  PRO FORMA         ADJUSTMENTS
                                                  HISTORICAL     ACQUISITION       FOR COMPLETED
                                                   LOCUSONE      ADJUSTMENTS       TRANSACTIONS
                                                  -----------    ------------      -------------
<S>                                               <C>            <C>               <C>
                                             ASSETS

Current assets:
  Cash and cash equivalents.....................  $    11,125    $(21,174,978)(A)  $(21,163,853)
  Trade accounts receivable, net................      256,423              --           256,423
  Prepaid expenses and other current assets.....        6,573              --             6,573
                                                  -----------    ------------      ------------
          Total current assets..................      274,121     (21,174,978)      (20,900,857)
Property and equipment, net.....................      197,821              --           197,821
Intangible assets, net..........................           --      39,868,502(A)     39,868,502
                                                  -----------    ------------      ------------
                                                  $   471,942    $ 18,693,524      $ 19,165,466
                                                  ===========    ============      ============

                              LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities:
  Accounts payable..............................  $    79,975    $         --      $     79,975
  Line of credit................................      858,000        (858,000)(A)            --
  Deferred revenue..............................      110,469              --           110,469
  Notes payable.................................           --      18,975,022(A)     18,975,022
                                                  -----------    ------------      ------------
          Total current liabilities.............    1,048,444      18,117,022        19,165,466
Redeemable preferred stock......................    2,250,000      (2,250,000)(A)            --
Stockholders' equity (deficit):
  Common stock..................................       45,000         (45,000)(A)            --
  Additional paid-in-capital....................      160,029        (160,029)(A)            --
  Accumulated deficit...........................   (3,031,531)      3,031,531(A)             --
                                                  -----------    ------------      ------------
Total stockholders' equity (deficit)............   (2,826,502)      2,826,502                --
                                                  -----------    ------------      ------------
                                                  $   471,942    $ 18,693,524      $ 19,165,466
                                                  ===========    ============      ============
</TABLE>

- ---------------

     (A) The LocusOne acquisition is to be accounted for as a purchase pursuant
         to Accounting Principles Board Opinion No. 16. Under such purchase
         accounting principles, LocusOne's assets acquired and liabilities
         assumed are required to be adjusted to their estimated fair values at
         the date of acquisition. The difference between the purchase cost and
         the fair value of LocusOne's net tangible and identifiable intangible
         assets is goodwill.

          The purchase price for LocusOne is as follows:

<TABLE>
<S>                                                       <C>
Cash consideration......................................  $21,024,978
Notes payable...........................................   18,975,022
Estimated costs and expenses............................      150,000
                                                          -----------
          Total purchase price..........................  $40,150,000
                                                          ===========
</TABLE>

          Aether made a payment of $20,000,000 at closing. In addition, Aether
          repaid outstanding indebtedness and certain legal fees of LocusOne
          totalling approximately $1,000,000. The remaining amount is payable in
          the form of two non-interest bearing notes payable. One note

                                      F-47
<PAGE>   300

          totaling $5.4 million is payable at the time of closing of this
          offering and the remaining $13.6 million is payable at December 31,
          2000.

          The allocation of the purchase price to the fair value of the assets
          acquired and liabilities assumed is preliminary and will be finalized
          following completion of a full valuation of the acquired assets and
          liabilities of LocusOne. The preliminary allocation of the purchase
          price is as follows:

<TABLE>
<S>                                                       <C>
Current assets..........................................  $   274,121
Fixed assets............................................      197,821
Current liabilities.....................................     (190,444)
Goodwill................................................   39,868,502
                                                          -----------
          Total purchase cost...........................  $40,150,000
                                                          ===========
</TABLE>

          The above purchase price allocation is preliminary and may change upon
          final determination of the fair value of assets and liabilities
          acquired. The Company has not specifically identified amounts to
          assign to intangibles other than goodwill; changes in the amounts
          allocated to such assets could result in changes to the amount of
          goodwill recorded, and such changes could be material. A preliminary
          amortization period for goodwill of five years has been used for
          purposes of the pro forma financial information.

                                      F-48
<PAGE>   301

                              AETHER SYSTEMS, INC.

            UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET
                      ADJUSTMENTS FOR PENDING TRANSACTION

<TABLE>
<CAPTION>
                                                             AS OF DECEMBER 31, 1999
                                                -------------------------------------------------
                                                                 PRO FORMA        ADJUSTMENTS FOR
                                                HISTORICAL      ACQUISITION           PENDING
                                                 RIVERBED       ADJUSTMENTS         TRANSACTION
                                                -----------    --------------     ---------------
<S>                                             <C>            <C>                <C>
                                             ASSETS
Current assets:
  Cash and cash equivalents...................  $ 5,340,801    $  (15,000,000)(A) $   (9,659,199)
  Short-term investments......................    3,936,542                --          3,936,542
  Trade accounts receivable, net..............      619,071                --            619,071
  Prepaid expenses and other current assets...      428,855                --            428,855
                                                -----------    --------------     --------------
          Total current assets................   10,325,269       (15,000,000)        (4,674,731)
Property and equipment, net...................      718,075                --            718,075
Intangible assets, net........................           --     1,126,324,412(A)   1,126,324,412
                                                ===========    ==============     ==============
                                                $11,043,344    $1,111,324,412     $1,122,367,756
                                                ===========    ==============     ==============
                              LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable............................  $   637,378    $           --     $      637,378
  Accrued expenses............................      497,135                --            497,135
  Notes payable...............................      120,578                --            120,578
  Deferred revenue............................       68,510                --             68,510
                                                -----------    --------------     --------------
          Total current liabilities...........    1,323,601                --          1,323,601
Notes payable.................................      241,155                --            241,155
                                                -----------    --------------     --------------
                                                  1,564,756                --          1,564,756
Redeemable preferred stock....................   15,771,520       (15,771,520)(A)             --
Stockholders' Equity
  Common stock................................       28,878            16,495(A)          45,373
  Additional paid-in-capital..................      561,033     1,120,196,594(A)   1,120,757,627
  Accumulated deficit.........................   (6,882,843)        6,882,843(A)              --
                                                -----------    --------------     --------------
Total stockholders' equity (deficit)..........   (6,292,932)    1,127,095,932      1,120,803,000
                                                ===========    ==============     ==============
                                                $11,043,344    $1,111,324,412     $1,122,367,756
                                                ===========    ==============     ==============
</TABLE>

- ---------------

(A) The pending acquisition of Riverbed will be accounted for as a purchase
    pursuant to Accounting Principles Board Opinion No. 16. Under such purchase
    accounting principles, Riverbed's assets acquired and liabilities assumed
    are required to be adjusted to their estimated fair values at the date of
    acquisition. The difference between the purchase cost and the fair value of
    Riverbed's net tangible and identifiable intangible assets is goodwill.

     The purchase price for Riverbed is as follows:

<TABLE>
<S>                                                    <C>
Issuance of Aether stock.............................  $  951,756,000
Issuance of replacement options......................     169,047,000
Estimated costs and expenses.........................      15,000,000
                                                       --------------
          Total purchase price.......................  $1,135,803,000
                                                       ==============
</TABLE>

     Aether will issue approximately 4,537,000 shares of its common stock for
all of the outstanding common and preferred stock of Riverbed. The Company has
valued the common stock based on the market price of Aether's common stock over
the period two days before and two days after the acquisition was agreed to and
announced, in accordance with FASB Emerging Issues Task Force Issue 95-19.
Aether has also reserved approximately 863,000 common shares for issuance upon
exercise of replacement options

                                      F-49
<PAGE>   302

to be issued to Riverbed employees. The value of these options was calculated
using the Black-Sholes option pricing model with the following assumptions:
expected dividend yield 0 percent, risk-free interest rate of 6.7 percent,
expected life of 5 years and volatility of 70 percent.

     The allocation of the purchase price to the fair value of the assets
acquired and liabilities assumed is preliminary and will be finalized following
completion of a full valuation of the assets and liabilities of Riverbed. The
preliminary allocation of the purchase price is as follows:

<TABLE>
<S>                                                    <C>
Current assets.......................................  $   10,325,269
Fixed assets.........................................         718,075
Current liabilities..................................      (1,323,601)
Long-term liabilities................................        (241,155)
Goodwill.............................................   1,126,324,412
                                                       --------------
          Total purchase cost........................  $1,135,803,000
                                                       ==============
</TABLE>

     The above purchase price allocation is preliminary and may change upon
final determination of the fair value of assets and liabilities acquired. The
Company has not specifically identified amounts to assign to intangibles other
than goodwill; changes in the amounts allocated to such assets could result in
changes to the amount of goodwill recorded, and such changes could be material.
A preliminary amortization period for goodwill of three years has been used for
purposes of the pro forma financial information. However, the results of the
full valuation may indicate that a portion of the purchase price should be
allocated to in-process research and development. Such amounts, if any, will be
expensed immediately following the date of acquisition. In addition, to the
extent that the full valuation indicates that a portion of the purchase price
should be allocated to identifiable intangible assets other than goodwill, the
Company may be required to record a deferred tax liability, as such intangible
assets would have no basis for tax reporting purposes.

                                      F-50
<PAGE>   303

                              AETHER SYSTEMS, INC.

       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS

<TABLE>
<CAPTION>
                                                    YEAR ENDED DECEMBER 31, 1999
                             ---------------------------------------------------------------------------
                                                             AETHER AS
                                             ADJUSTMENTS    ADJUSTED FOR    ADJUSTMENTS
                              HISTORICAL    FOR COMPLETED    COMPLETED      FOR PENDING      PRO FORMA
                                AETHER      TRANSACTIONS    TRANSACTIONS    TRANSACTION    CONSOLIDATED
                             ------------   -------------   ------------   -------------   -------------
<S>                          <C>            <C>             <C>            <C>             <C>
Subscriber revenue.........  $  3,731,792   $  7,467,834    $ 11,199,626   $          --   $  11,199,626
Engineering services
  revenue..................     2,594,476             --       2,594,476              --       2,594,476
Software and related
  services revenue.........            --      1,489,923       1,489,923         827,085       2,317,008
                             ------------   ------------    ------------   -------------   -------------
     Total revenue.........     6,326,268      8,957,757      15,284,025         827,085      16,111,110
Cost of subscriber
  revenue..................     2,109,807      2,529,296       4,639,103              --       4,639,103
Cost of engineering
  services revenue.........     1,366,426             --       1,366,426              --       1,366,426
Cost of software and
  related services
  revenue..................            --        813,203         813,203         727,484       1,540,687
                             ------------   ------------    ------------   -------------   -------------
     Total cost of
       revenue.............     3,476,233      3,342,499       6,818,732         727,484       7,546,216
                             ------------   ------------    ------------   -------------   -------------
          Gross profit.....     2,850,035      5,615,258       8,465,293          99,601       8,564,894
                             ------------   ------------    ------------   -------------   -------------
Operating expenses:
  Research and
     development...........     2,613,726        816,712       3,430,438       2,050,778       5,481,216
  General and
     administrative........     5,891,504      1,966,594       7,858,098       1,055,071       8,913,169
  Selling and marketing....     2,095,074      1,870,565       3,965,639       2,865,470       6,831,109
  Depreciation and
     amortization..........     1,089,013      9,820,307      10,909,320     375,441,471     386,350,791
  Option and warrant
     expense...............    19,198,209     13,124,936      32,323,145       1,200,294      33,523,439
                             ------------   ------------    ------------   -------------   -------------
                               30,887,526     27,599,114      58,486,640     382,613,084     441,099,724
                             ------------   ------------    ------------   -------------   -------------
          Operating loss...   (28,037,491)   (21,983,856)    (50,021,347)   (382,513,483)   (432,534,830)
Other income (expense):
  Interest income
     (expense), net........       (60,282)        17,594         (42,688)        150,748         108,060
  Equity in losses of
     investments...........    (2,425,000)            --              --              --      (2,425,000)
  Realized loss on sale of
     short-term
     investments...........      (168,721)            --              --              --        (168,721)
                             ------------   ------------    ------------   -------------   -------------
     Net loss..............  $(30,691,494)  $(21,966,262)   $(50,064,035)  $(382,362,735)  $(435,020,491)
                             ============   ============    ============   =============   =============
Pro forma net loss per
  share -- basic and
  diluted..................                                                                $      (16.90)
                                                                                           =============
Pro forma weighted average
  shares used in per share
  computations -- basic and
  diluted..................                                                                   25,744,511
                                                                                           =============
</TABLE>

                                      F-51
<PAGE>   304

                              AETHER SYSTEMS, INC.

                   UNAUDITED PRO FORMA CONDENSED CONSOLIDATED
                     STATEMENT OF OPERATIONS -- (CONTINUED)

<TABLE>
<CAPTION>
                                                           YEAR ENDED DECEMBER 31, 1999
                                 --------------------------------------------------------------------------------
                                                   PRO FORMA                         PRO FORMA        PRO FORMA
                                   PRO FORMA     DEBT OFFERING       PRO FORMA     STOCK OFFERING    AS FURTHER
                                 CONSOLIDATED     ADJUSTMENTS       AS ADJUSTED     ADJUSTMENTS       ADJUSTED
                                 -------------   -------------     -------------   --------------   -------------
<S>                              <C>             <C>               <C>             <C>              <C>
Subscriber revenue.............  $  11,199,626   $         --      $  11,199,626    $         --    $  11,199,626
Engineering services revenue...      2,594,476             --          2,594,476              --        2,594,476
Software and related services
  revenue......................      2,317,008             --          2,317,008              --        2,317,008
                                 -------------   ------------      -------------    ------------    -------------
    Total revenue..............     16,111,110             --         16,111,110              --       16,111,110
Cost of subscriber revenue.....      4,639,103             --          4,639,103              --        4,639,103
Cost of engineering services
  revenue......................      1,366,426             --          1,366,426              --        1,366,426
Cost of software and related
  services revenue.............      1,540,687             --          1,540,687              --        1,540,687
                                 -------------   ------------      -------------    ------------    -------------
    Total cost of revenue......      7,546,216             --          7,546,216              --        7,546,216
                                 -------------   ------------      -------------    ------------    -------------
         Gross profit..........      8,564,894             --          8,564,894              --        8,564,894
                                 -------------   ------------      -------------    ------------    -------------
Operating expenses:
  Research and development.....      5,481,216             --          5,481,216              --        5,481,216
  General and administrative...      8,913,169             --          8,913,169              --        8,913,169
  Selling and marketing........      6,831,109             --          6,831,109              --        6,831,109
  Depreciation and
    amortization...............    386,350,791             --        386,350,791              --      386,350,791
  Option and warrant expense...     33,523,439             --         33,523,439              --       33,523,439
                                 -------------   ------------      -------------    ------------    -------------
                                   441,099,724             --        441,099,724              --      441,099,724
                                 -------------   ------------      -------------    ------------    -------------
         Operating loss:.......   (432,534,830)            --       (432,534,830)             --     (432,534,830)
Other income (expense):
  Interest income (expense),
    net........................        108,060    (14,440,000)(A)    (14,331,940)             --      (14,331,940)
  Equity in losses of
    investments................     (2,425,000)            --         (2,425,000)             --       (2,425,000)
  Realized loss on sale of
    short-term investments.....       (168,721)            --           (168,721)             --         (168,721)
                                 -------------   ------------      -------------    ------------    -------------
    Net loss...................  $(435,020,491)  $(14,440,000)     $(449,460,491)   $         --    $(449,460,491)
                                 =============   ============      =============    ============    =============
Pro forma net loss per share
  basic and diluted............  $      (16.90)                    $      (17.45)                   $      (15.92)
                                 =============                     =============                    =============
Pro forma weighted average
  shares used in per share
  computations -- basic and
  diluted......................     25,744,511                        25,744,511                       28,235,730(B)
                                 =============                     =============                    =============
</TABLE>

- ----------------
(A) Reflects interest expense associated with the sale of an aggregate $200
    million of convertible subordinated notes due in 2005 in the offering at an
    assumed interest rate of 6.5%.

(B) Reflects the sale of 2,346,219 shares of common stock in the concurrent
    offering and the exercise of options to purchase 145,000 shares by the
    selling stockholders.

                                      F-52
<PAGE>   305

                              AETHER SYSTEMS, INC.

       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
                     ADJUSTMENTS FOR COMPLETED TRANSACTIONS

<TABLE>
<CAPTION>
                          PERIOD FROM JANUARY 1, 1999               YEAR ENDED
                           THROUGH SEPTEMBER 28, 1999           DECEMBER 31, 1999
                          ----------------------------     ----------------------------    ADJUSTMENTS
                                           PRO FORMA                        PRO FORMA          FOR
                           HISTORICAL     ACQUISITION      HISTORICAL      ACQUISITION      COMPLETED
                            MOBEO(A)      ADJUSTMENTS       LOCUS ONE      ADJUSTMENTS     TRANSACTIONS
                          ------------   -------------     -----------     ------------    ------------
<S>                       <C>            <C>               <C>             <C>             <C>
Subscriber revenue......   $7,467,834     $        --      $        --     $         --    $  7,467,834
Software and related
  services revenue......           --              --        1,489,923               --       1,489,923
                           ----------     -----------      -----------     ------------    ------------
     Total revenue......    7,467,834              --        1,489,923               --       8,957,757
                           ----------     -----------      -----------     ------------    ------------
Cost of subscriber
  revenue...............    2,529,296              --               --               --       2,529,296
Cost of software and
  related services
  revenue...............           --              --          813,203               --         813,203
                           ----------     -----------      -----------     ------------    ------------
     Total cost of
       revenue..........    2,529,296              --          813,203               --       3,342,499
                           ----------     -----------      -----------     ------------    ------------
     Gross profit.......    4,938,538              --          676,720               --       5,615,258
                           ----------     -----------      -----------     ------------    ------------
Operating expenses:
  Research and
     development........      763,666              --           53,046               --         816,712
  General and
     administrative.....    1,994,525        (855,891)(C)      827,960               --       1,966,594
  Selling and
     marketing..........    2,069,413        (740,921)(C)      542,073               --       1,870,565
  Depreciation and
     amortization.......       82,915       1,667,511(B)        96,181        7,973,700(E)    9,820,307
  Option and warrant
     expense............           --       1,225,875(D)       299,561       11,599,500(F)   13,124,936
                           ----------     -----------      -----------     ------------    ------------
                            4,910,519       1,296,574        1,818,821       19,573,200      27,599,114
                           ----------     -----------      -----------     ------------    ------------
     Operating income
       (loss)...........       28,019      (1,296,574)      (1,142,101)     (19,573,200)    (21,983,856)
Other income (expense):
  Interest income
     (expense), net.....       17,594              --          (20,125)          20,125(G)       17,594
                           ----------     -----------      -----------     ------------    ------------
     Net income
       (loss)...........   $   45,613     $(1,296,574)     $(1,162,226)    $(19,553,075)   $(21,966,262)
                           ==========     ===========      ===========     ============    ============
</TABLE>

- ---------------

     (A) Reflects the historical results of Mobeo for the period from January 1,
         1999 to September 28, 1999. The results of Mobeo from September 29,
         1999 to December 31, 1999 are included in Aether's historical results
         for the year ended December 31, 1999.

     (B) Reflects the amortization of intangible assets, including goodwill,
         over three to seven year periods.

     (C) Reflects the elimination of compensation expense associated with
         certain management employees of Mobeo who ceased employment following
         the acquisition and who were not replaced.

     (D) Reflects the amortization of the estimated fair value of options
         granted to two former owners of Mobeo for consulting services over the
         two-year life of the consulting arrangement. Also reflects amortization
         of the intrinsic value of options granted to employees of Mobeo over
         the vesting period.

                                      F-53
<PAGE>   306

     (E) Reflects the amortization of intangible assets, including goodwill,
         over a five-year period. The estimated amount of amortization of
         intangible assets is based on a preliminary allocation of the purchase
         price and may change upon final determination, and such change could be
         material.

     (F) Reflects the amortization of the intrinsic value of options granted to
         employees of LocusOne over the three-year vesting period.

     (G) Reflects the elimination of interest expense, as LocusOne's outstanding
         debt was repaid by Aether as part of the acquisition.

                                      F-54
<PAGE>   307

                              AETHER SYSTEMS, INC.

       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
                      ADJUSTMENTS FOR PENDING TRANSACTION

<TABLE>
<CAPTION>
                                                         YEAR ENDED DECEMBER 31, 1999
                                              --------------------------------------------------
                                                               PRO FORMA         ADJUSTMENTS FOR
                                              HISTORICAL      ACQUISITION            PENDING
                                               RIVERBED       ADJUSTMENTS          TRANSACTION
                                              -----------    -------------       ---------------
<S>                                           <C>            <C>                 <C>
Software and related services revenue.....    $   927,085    $    (100,000)(A)    $     827,085
Cost of software and related services
  revenue.................................        727,484               --              727,484
                                              -----------    -------------        -------------
          Gross profit....................        199,601         (100,000)              99,601
                                              -----------    -------------        -------------
Operating expenses:
  Research and development................      2,050,778               --            2,050,778
  General and administrative..............      1,055,071               --            1,055,071
  Selling and marketing...................      2,865,470               --            2,865,470
  Depreciation and amortization...........             --      375,441,471(B)       375,441,471
  Option and warrant expense..............      1,200,294               --            1,200,294
                                              -----------    -------------        -------------
                                                7,171,613      375,441,471          382,613,084
                                              -----------    -------------        -------------
     Operating loss.......................     (6,972,012)    (375,541,471)        (382,513,483)
Other income (expense):
  Interest income (expense), net..........        150,748               --              150,748
                                              -----------    -------------        -------------
     Net loss.............................    $(6,821,264)   $(375,541,471)       $(382,362,735)
                                              ===========    =============        =============
</TABLE>

- ---------------

(A) Reflects the elimination of software revenue related to a sale by Riverbed
    to the Company. The cost of such sale has not been eliminated, as the
    amounts are insignificant.

(B) Reflects the amortization of intangible assets, including goodwill, over a
    three-year period. The purchase price allocation is preliminary and may
    change upon final determination of the fair value of assets and liabilities
    acquired. The Company has not specifically identified amounts to assign to
    intangibles other than goodwill; changes in the amounts allocated to such
    assets could result in changes to the amount of goodwill recorded, and such
    changes could be material. A preliminary amortization period for goodwill of
    three years has been used for purposes of the pro forma financial
    information. However, the results of the full valuation may indicate that a
    portion of the purchase price should be allocated to in-process research and
    development. Such amounts, if any, will be expensed immediately following
    the date of acquisition. In addition, to the extent that the full valuation
    indicates that a portion of the purchase price should be allocated to
    identifiable intangible assets other than goodwill, the Company may be
    required to record a deferred tax liability, as such intangible assets would
    have no basis for tax reporting purposes. This may result in recording
    additional goodwill amortization and a deferred tax benefit.

                                      F-55
<PAGE>   308

    ----------------------------------------------------------------------------
     ---------------------------------------------------------------------------

                                                    $200,000,000

                                    [AETHER LOGO]

                       % CONVERTIBLE SUBORDINATED NOTES DUE 2005

                          --------------------------------

                                     PROSPECTUS
                          --------------------------------

                                 MERRILL LYNCH & CO.

                                 ROBERTSON STEPHENS

                            DONALDSON, LUFKIN & JENRETTE

                             U.S. BANCORP PIPER JAFFRAY

                              BEAR, STEARNS & CO. INC.

                              FRIEDMAN BILLINGS RAMSEY

                                               , 2000

     ---------------------------------------------------------------------------
     ---------------------------------------------------------------------------
<PAGE>   309

                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

     The expenses to be paid by Aether Systems, Inc. ("Aether" or "Aether
Systems") in connection with the distribution of the securities being
registered, other than underwriting discounts and commission, are as follows:

<TABLE>
<CAPTION>
                                                                       CONVERTIBLE
                                                           COMMON      SUBORDINATED      TOTAL
                                                           STOCK          NOTES        AMOUNT(1)
                                                         ----------    ------------    ----------
<S>                                                      <C>           <C>             <C>
Securities and Exchange Commission Registration Fee....  $  183,982     $   60,720     $  244,702
NASD Filing Fee........................................      30,500         23,500         54,000
Nasdaq National Market Listing Fee.....................      17,500             --         17,500
Accounting Fees and Expenses...........................     300,000        300,000        600,000
Blue Sky Fees and Expenses.............................       7,500          7,500         15,000
Legal Fees and Expenses................................     400,000        400,000        800,000
Transfer Agent and Registrar Fees and Expenses.........          --         10,000         10,000
Printing and Engraving Expenses........................     175,000        175,000        350,000
Miscellaneous Fees and Expenses........................     185,518        223,280        408,798
                                                         ----------     ----------     ----------
          Total........................................  $1,300,000     $1,200,000     $2,500,000
                                                         ==========     ==========     ==========
</TABLE>

- ---------------
(1) All amounts are estimates except the SEC filing fee, the NASD filing fee and
    the Nasdaq National Market listing fee.

ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS

     Under Section 145 of the General Corporate law of the State of Delaware,
Aether Systems has broad powers to indemnify its directors and officers against
liabilities they may incur in such capacities, including liabilities under the
Securities Act of 1933, as amended (the "Securities Act"). Aether Systems'
bylaws (Exhibit 3.2 hereto) also provide for mandatory indemnification of its
directors and executive officers, and permissive indemnification of its
employees and agents, to the fullest extent permissible under Delaware law.

     Aether's certificate of incorporation (Exhibit 3.1 hereto) provides that
the liability of its directors for monetary damages shall be eliminated to the
fullest extent permissible under Delaware law. Pursuant to Delaware law, this
includes elimination of liability for monetary damages for breach of the
directors' fiduciary duty of care to Aether and its stockholders. These
provisions do not eliminate the directors' duty of care and, in appropriate
circumstances, equitable remedies such as injunctive or other forms of non-
monetary relief will remain available under Delaware law. In addition, each
director will continue to be subject to liability for breach of the director's
duty of loyalty to Aether, for acts or omissions not in good faith or involving
intentional misconduct, for knowing violations of law, for any transaction from
which the director derived an improper personal benefit, and for payment of
dividends or approval of stock repurchases or redemptions that are unlawful
under Delaware law. The provision also does not affect a director's
responsibilities under any other laws, such as the federal securities laws or
state or federal environmental laws.

     Aether has entered into agreements with its directors and certain of its
executive officers that require Aether to indemnify such persons against
expenses, judgments, fines, settlements and other amounts actually and
reasonably incurred (including expenses of a derivative action) in connection
with any proceeding, whether actual or threatened, to which any such person may
be made a party by reason of the fact that such person is or was a director or
officer of Aether or any of its affiliated enterprises, provided

                                      II-1
<PAGE>   310

such person acted in good father and in a manner such person reasonably believed
to be in or not opposed to the best interests of Aether and, with respect to any
criminal proceeding, had no reasonable cause to believe his or her conduct was
unlawful. The indemnification agreements also set forth certain procedures that
will apply in the event of a claim for indemnification thereunder.

     Aether has a policy of directors' and officers' liability insurance that
insures Aether's directors and officers against the cost of defense, settlement
or payment of a judgment under certain circumstances.

     The Underwriting Agreement filed as Exhibit 1.1 to this Registration
Statement provides for indemnification by the underwriters of Aether and its
officers and directors for certain liabilities arising under the Securities Act
or otherwise.

ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES

     Since its inception, Aether Systems, Inc. or its predecessors, Aether
Systems LLC or Aether Technologies International, L.L.C. ("Aether") has issued
and sold unregistered securities in the transactions described below.
Immediately prior to our initial public offering, we converted into a Delaware
corporation at which time each holder of units in our limited liability company
was converted into two and one-half shares of our common stock and each option
or warrant for one unit was converted into an option or warrant for two and
one-half shares of our common stock. The discussion below gives only the number
of shares into which units were converted.

     1) In January 1996, NexGen Technologies, L.L.C. contributed assets in the
wireless data field to Aether in exchange for 7,500,000 shares and
Transettlements, Inc. contributed $1,000,000 in cash in exchange for 2,500,000
shares. On May 21, 1996, Transettlements contributed an additional $500,000 in
exchange for an additional 1,250,000 shares.

     2) In February 1997, a subsidiary of Telcom Ventures, L.L.C. acquired
725,000 shares from Transettlements and contributed $1,000,000 to Aether in
exchange for 1,562,500 shares. In December 1997, Telcom Ventures and its
subsidiary contributed an additional $690,369 to Aether in exchange for an
additional 575,307.5 shares.

     3) In January 1998, Pyramid Ventures, Inc., a subsidiary of Bankers Trust
Corporation, acquired 833,332.5 shares at $1.20 per share and 1,004,902.5 shares
at $1.49 per share for total proceeds to Aether LLC of approximately $2.5
million.

     In June 1998, Telcom Ventures and Pyramid each loaned us $250,000. The
notes accrued interest at 8% per year and were due on demand with a stated
maturity date of the earlier of December 31, 1998 or the closing of an
anticipated private placement of units. The notes were convertible into units at
the option of the holder at the rate of $250,000 divided by the per unit price
to be paid in the anticipated private placements. In connection with the
issuance of these notes, we also issued 14,140 warrants with an exercise price
of $0.01 per unit to each of Telcom Ventures and Pyramid. Pyramid converted its
$250,000 loan plus accrued interest in August 1998 into 142,950 shares at a per
share price of $1.77 and exercised its warrant and acquired 14,140 shares. In
August 1998, we repaid the amount owed Telcom Ventures, including $2,520 in
interest. Telcom Ventures exercised its warrant and received 14,140 shares in
August 1999.

     4) In August 1998, Reuters MarketClip Holdings Sarl received 2,828,055
shares in exchange for $4,735,020 in cash and forgiveness of $530,980 Aether
owed Reuters for hardware and other inventory, offset by $266,000 Reuters owed
us under a license agreement we previously entered into with Reuters relating to
sales of MarketClip, and related fees.

     5) In October 1998, 3Com Corporation contributed $6,000,000, in exchange
for 2,500,000 shares. At the same time Aether issued 3Com a conditional warrant
to purchase 893,665 shares exercisable at $0.01 per unit if the milestones
described below are achieved before October 29, 2001. 3Com achieved the first
milestone entitling it to exercise 143,665 shares as a result of having
completed a joint sales and marketing plan. 3Com may exercise an additional
375,000 shares when Aether receives revenue of $6 million in

                                      II-2
<PAGE>   311

engineering services revenue from business opportunities introduced by 3Com.
3Com may exercise an additional 375,000 shares if Aether attains 6,000 wireless
service subscribers as a result of business opportunities introduced to us by
3Com. 3Com has not attained either of these last two milestones and has not
exercised any of its warrants.

     6) Aether from time to time has granted options or warrants to acquire
units to employees and members of the managing board. The following table sets
forth certain information regarding such grants:

<TABLE>
<CAPTION>
                                                          RANGE OF
                    NO. OF SHARES                      EXERCISE PRICES
                    -------------                      ---------------
<S>                                                    <C>
1996  693,438                                          $0.40
1997  306,562                                          $0.40
1998  604,688                                          $1.49-$1.77
1999  2,763,856                                        $1.77-$79.75
</TABLE>

     7) In August 1999, Aether issued 100,000 shares pursuant to Mr. Ein's
exercise of an option for shares at an exercise price of $.40 per share. On
September 8, 1999, Mr. Beese exercised an option for 75,000 shares at an
exercise price of $.40 per share.

     8) On September 28, 1999, we issued to Merrill Lynch Capital Corporation in
connection with a credit facility warrants to purchase up to 2,419,690 shares of
our common stock for no consideration. These warrants expired when we repaid
allotments owing under the credit facility from the proceeds of in our initial
public offering.

     9) On September 28, 1999, we issued options for 488,605 shares in
connection with Aether's acquisition of Mobeo, Inc. The exercise price of
options for (1) 312,500 shares is $6.00 per share, (2) 116,105 shares is $4.80
per share, and (3) 60,000 shares is $2.40 per share.

     10) On February 9, 2000, we entered into an agreement with Riverbed
Technologies, Inc. for an aggregate of 5,400,000 shares of our common stock. We
agreed to issue approximately 4.5 million shares in exchange for all of the
issued and outstanding capital stock of Riverbed and to reserve an additional
900,000 shares of our common stock reserved for issuance upon exercise of
options previously issued to Riverbed employees.

     The sale and issuance of securities in the transactions described above
were exempt from registration under the Securities Act in reliance on Section
4(2) of the Securities Act or Regulation D promulgated thereunder as
transactions by an issuer not involving a public offering, where the purchasers
were sophisticated investors who represented their intention to acquire
securities for investment only and not with a view to distribution and received
or had access to adequate information about the Aether. Some of the options
identified in sub-items 6 and 10 were exempt from registration pursuant to Rule
701 under the Securities Act.

     No underwriters were employed in any of the above transactions.

ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

     Exhibits

     The exhibit index is incorporated by reference.

     Financial Statement Schedules

     Schedule II

     Schedules other than those listed above have been omitted since they are
not required or are not applicable or the required information is shown in the
financial statements or related notes. Columns omitted from schedules filed have
been omitted since the information is not applicable.

                                      II-3
<PAGE>   312

ITEM 17. UNDERTAKINGS

     The undersigned registrant hereby undertakes to provide to the underwriters
at the closing specified in the underwriting agreements, certificates in such
denominations and registered in such names as required by the underwriters to
permit prompt delivery to each purchaser.

     Insofar as indemnification for liabilities arising under the Securities Act
of 1933, as amended (the "Act") may be permitted to directors, officers and
controlling persons of the registrant pursuant to the foregoing provisions, or
otherwise, the registrant has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Act and is, therefore, unenforceable.

     In the event that a claim for indemnification against such liabilities
(other than the payment by the registrant of expenses incurred or paid by a
director, officer or controlling person of the registrant in the successful
defense of any action, suit or proceeding) is asserted by such director, officer
or controlling person in connection with the securities being registered, the
registrant will, unless in the opinion of its counsel the matter has been
settled by controlling precedent, submit to a court of appropriate jurisdiction
the question whether such indemnification by it is against public policy as
expressed in the Act and will be governed by the final adjudication of such
issue.

     The undersigned registrant hereby undertakes that:

          (1) For purposes of determining any liability under the Securities Act
     of 1933, the information omitted from the form of prospectus filed as part
     of this registration statement in reliance upon Rule 430A and contained in
     a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or
     (4) or 497(h) under the Securities Act shall be deemed to be part of this
     registration statement as of the time it was declared effective.

          (2) For the purpose of determining any liability under the Securities
     Act of 1933, each post-effective amendment that contains a form of
     prospectus shall be deemed to be a new registration statement relating to
     the securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.

                                      II-4
<PAGE>   313

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the registrant
has duly caused this registration statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of Owings Mills, State of
Maryland on the 22nd day of February, 2000.

                                            Aether Systems, Inc.

                                            By: /s/ DAVID S. OROS
                                              ----------------------------------
                                                David S. Oros
                                                Chairman, President and Chief
                                                Executive Officer

                               POWER OF ATTORNEY

     KNOW BY ALL PERSONS, that each person whose signature appears below
constitutes and appoints David Oros and David C. Reymann, and each of them, as
his true and lawful attorneys-in-fact and agents, with full power of
substitution and resubstitution, for him and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post-effective
amendments) to this Registration Statement and sign any registration statement
for the same offering covered by the Registration Statement that is to be
effective upon filing pursuant to Rule 462 promulgated under the Securities Act
of 1933, and to file the same, with all exhibits thereto, and other documents in
connection therewith, with the Securities and Exchange Commission, granting unto
said attorneys-in-fact and agents, and each of them, full power and authority to
do and perform each and every act and thing requisite and necessary to be done
in connection therewith and about the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact and agents, or any of them, or their or his
substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>
                      SIGNATURE                                      TITLE                        DATE
                      ---------                                      -----                        ----

<S>                                                    <C>                                 <C>

                  /s/ DAVID S. OROS                      Chairman, President and Chief     February 22, 2000
- -----------------------------------------------------          Executive Officer
                    David S. Oros

                /s/ DAVID C. REYMANN                   Chief Financial Officer (Principal  February 22, 2000
- -----------------------------------------------------  Financial and Accounting Officer)
                  David C. Reymann

              /s/ J. CARTER BEESE, JR.                              Director               February 22, 2000
- -----------------------------------------------------
                J. Carter Beese, Jr.

              /s/ FRANK A. BONSAL, JR.                              Director               February 22, 2000
- -----------------------------------------------------
                Frank A. Bonsal, Jr.

                   /s/ MARK D. EIN                                  Director               February 22, 2000
- -----------------------------------------------------
                     Mark D. Ein

                                                                    Director               February   , 2000
- -----------------------------------------------------
                  Rahul C. Prakash
</TABLE>

                                      II-5
<PAGE>   314

<TABLE>
<CAPTION>
                      SIGNATURE                                      TITLE                        DATE
                      ---------                                      -----                        ----

<S>                                                    <C>                                 <C>
                                                                    Director               February   , 2000
- -----------------------------------------------------
                  Janice M. Roberts

                 /s/ RAJENDRA SINGH                                 Director               February 22, 2000
- -----------------------------------------------------
                 Dr. Rajendra Singh

                /s/ GEORGE P. STAMAS                                Director               February 22, 2000
- -----------------------------------------------------
                    George Stamas

                                                                    Director               February   , 2000
- -----------------------------------------------------
                   Devin N. Wenig

                /s/ THOMAS E. WHEELER                               Director               February 22, 2000
- -----------------------------------------------------
                  Thomas E. Wheeler
</TABLE>

                                      II-6
<PAGE>   315

                                  SCHEDULE II
                       VALUATION AND QUALIFYING ACCOUNTS
                  YEARS ENDED DECEMBER 31, 1997, 1998 AND 1999

<TABLE>
<CAPTION>
                                                   BALANCE AT   CHARGED TO                BALANCE AT
                                                   BEGINNING    COSTS AND                    END
                   DESCRIPTION                      OF YEAR      EXPENSES    DEDUCTIONS    OF YEAR
                   -----------                     ----------   ----------   ----------   ----------
<S>                                                <C>          <C>          <C>          <C>
1997
Allowance for doubtful accounts..................   $     --     $     --     $     --     $     --
Allowance for inventory obsolescence.............         --           --           --           --
1998
Allowance for doubtful accounts..................         --      157,061           --      157,061
Allowance for inventory obsolescence.............         --      169,630           --      169,630
1999
Allowance for doubtful accounts..................    157,061      (59,530)      41,160       56,371
Allowance for inventory obsolescence.............    169,630      (54,477)          --      115,153
</TABLE>
<PAGE>   316

                                 EXHIBIT INDEX

<TABLE>
<CAPTION>
        EXHIBIT
         NUMBER                            DOCUMENT AND DESCRIPTION
        -------                            ------------------------
<C>                      <S>
         ***1.1          -- Form of U.S. Purchase Agreement for U.S. Offering of
                            Common Stock
         ***1.2          -- Form of International Purchase Agreement for
                            International Offering of Common Stock
         ***1.3          -- Form of Purchase Agreement for Convertible Subordinated
                            Note Offering
           *2.1          -- Agreement of Merger, dated as of October 18, 1999,
                            between Aether Systems LLC, and Aether Systems, Inc.
           *2.2          -- Stock Purchase Agreement by and among Aether Technologies
                            International, L.L.C., Mobeo, Inc. and Peter Kibler,
                            Winston Barrett and Edward Spear dated as of August 19,
                            1999.
          **2.3          -- Stock Purchase Agreement by and among Aether Systems,
                            Inc., LocusOne Communications, Inc. and the stockholders
                            named therein dated as of January 25, 2000
            2.4          -- Agreement and Plan of Merger dated as of February 9, 2000
                            by and among Aether Systems, Inc., RT Acquisition, Inc.
                            and Riverbed Technologies, Inc.
           *3.1          -- Amended and Restated Certificate of Incorporation of
                            Aether Systems, Inc.
           *3.2          -- Bylaws of Aether Systems, Inc.
           *4.1          -- Specimen Certificate for Aether Systems Common Stock
         ***4.2          -- Form of Indenture for Convertible Debt
         ***5.1          -- Opinion of Wilmer, Cutler & Pickering as to the legality
                            of the shares of Common Stock being registered
         ***5.2          -- Opinion of Wilmer, Cutler & Pickering as to the legality
                            of the convertible notes being registered
          *10.1          -- Amended and Restated License, Marketing and Distribution
                            Agreement between Reuters America, Inc. and Aether
                            Technologies International, L.L.C. dated August 11, 1998.
          *10.2          -- Contract Between Morgan Stanley Dean Witter Online
                            Direct, Inc. and Aether Technologies International,
                            L.L.C. dated August 5, 1999.
          *10.3          -- Options Price Reporting Authority Vendor Agreement
                            between Aether Technologies and the American Stock
                            Exchange, Inc. dated June 3, 1997.
          *10.4          -- Agreement between Aether Technologies International,
                            L.L.C. and New York Stock Exchange dated July 19, 1999.
          *10.5          -- Vendor Agreement by and between Aether Technologies
                            International, L.L.C. and the Nasdaq Stock Market, Inc.
                            dated October 4, 1996.
          *10.6          -- Dow Jones Indexes Enterprise Distribution Agreement dated
                            April 23, 1999.
          *10.7          -- Employment Agreement between Aether Technologies
                            International, L.L.C. and David Oros dated July 7, 1999.
          *10.8          -- Employment Agreement between Aether Technologies
                            International, L.L.C. and David Reymann dated May 18,
                            1999.
          *10.9          -- Series A Preferred Stock Purchase Agreement dated as of
                            August 9, 1999.
          *10.10         -- Investors' Rights Agreement by and among AirWeb
                            Corporation and each of the holder of the Series A
                            Preferred Stock listed in Schedule A and Patrick McVeigh,
                            Barak Berkowitz, Michael Bolbec and Andrew Simms dated
                            August 9, 1999.
          *10.11         -- Right of First Refusal and Co-Sale Agreement by and among
                            AirWeb Corporation, Inc., and those holders of the Common
                            Stock identified in Schedule A and B dated August 9,
                            1999.
          *10.12         -- Voting Agreement by and among the holders of Common Stock
                            set forth in Schedule A and Purchase of the Series A
                            Preferred Stock dated August 9, 1999.
          *10.13         -- Aether-OmniSky Side Letter regarding development and
                            resale services dated August 9, 1999.
</TABLE>
<PAGE>   317

<TABLE>
<CAPTION>
        EXHIBIT
         NUMBER                            DOCUMENT AND DESCRIPTION
        -------                            ------------------------
<C>                      <S>
          *10.14         -- Software License Agreement by and between Aether
                            Technologies International, L.L.C. and AirWeb Corporation
                            dated August 9, 1999.
          *10.15         -- AirWeb Corporation Warrant to Purchase 3,000,000 Shares
                            of Series A Preferred Stock dated August 9, 1999.
          *10.16         -- Strategic License Agreement between Aether Technologies
                            International, L.L.C. and Riverbed Technologies, Inc.
                            dated as of June 15, 1999.
          *10.17         -- Consulting Agreement between Aether Technologies, L.L.C.
                            and Orbcomm Global, L.P. dated as of October 26, 1998.
          *10.18         -- Credit Agreement dated as of September 28, 1999 among
                            Merrill Lynch & Co. and the leaders named therein.
          *10.19         -- Aether Systems, Inc. 1999 Equity Incentive Plan effective
                            as of October 1, 1999
          *10.20         -- Aether Systems, Inc. Senior Bonus Plan effective as of
                            September 29, 1999
          *10.21         -- Amended and Restated Registration Rights Agreement dated
                            as of February 2000
          *10.22         -- Form of Subscription Agreement between Aether Systems,
                            Inc. and National Discount Brokers
           10.23         -- Series B Preferred Stock Purchase Agreement dated as of
                            January 18, 2000
           10.24         -- Master Agreement between Aether Systems, Inc. and Charles
                            Schwab & Co., Inc., dated as of December 23, 1999
           10.25         -- Inciscent, Inc. Series A Stock Purchase Agreement
           10.26         -- Agreement between National Discount Brokers Corporation
                            and Aether Systems, Inc., dated as of November 4, 1999
           10.27         -- Development Agreement between Response Services, LLC and
                            Aether Systems, Inc. dated as of January 12, 2000
           11.1          -- Statement regarding computation of per share earnings.
           11.2          -- Statement regarding computation of ratios
           21.1          -- Subsidiaries of Aether Systems
           23.1          -- Consent of KPMG LLP for Aether Systems, Inc.
           23.2          -- Consent of PricewaterhouseCoopers LLP
        ***23.3          -- Consent of Wilmer, Cutler & Pickering, included in
                            Exhibit 5.1
           23.4          -- Consent of E. Wayne Jackson
           23.5          -- Consent of Robin T. Vasan
           23.6          -- Consent of the Forrester Research
           23.7          -- Consent of International Data Corporation
           23.8          -- Consent of KPMG LLP for Riverbed Technologies, Inc.
           24.1          -- Power of Attorney, included on the signature page hereof
        ***25.1          -- Statement on Form T-1 of Eligibility of Trustee
</TABLE>

- ---------------
     * Incorporated by reference to the Registration Statement as amended (File
       No. 333-85697) on Form S-1 filed with the Commission on October 20, 1999.

   ** Incorporated by reference to the Form 8-K filed with the Commission on
      February 15, 2000.

  *** To be filed by amendment.

<PAGE>   1

                                                                     EXHIBIT 2.4

                          AGREEMENT AND PLAN OF MERGER

                          dated as of February 9, 2000

                                  by and among

                              AETHER SYSTEMS, INC.,

                              RT ACQUISITION, INC.

                                       and

                           RIVERBED TECHNOLOGIES, INC.


<PAGE>   2


iii

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                                  PAGE

<S>                           <C>                                                                                  <C>
ARTICLE I. DEFINITIONS................................................................................................1
             Section 1.1      Definitions.............................................................................1

ARTICLE II. THE MERGER...............................................................................................10
             Section 2.1      The Merger.............................................................................10
             Section 2.2      Effective Time of the Merger...........................................................10
             Section 2.3      Closing................................................................................10
             Section 2.4      Effects of the Merger..................................................................10
             Section 2.5      Certificate of Incorporation and Bylaws................................................10
             Section 2.6      Directors of the Surviving Corporation.................................................11
             Section 2.7      Officers of the Surviving Corporation..................................................11

ARTICLE III. CONVERSION OF SECURITIES................................................................................12
             Section 3.1      Conversion of Capital Stock of Merger Sub..............................................12
             Section 3.2      Conversion of Riverbed Capital Stock...................................................12
             Section 3.3      Conversion of Riverbed Options.........................................................12
             Section 3.4      General Conversion Mechanics...........................................................12
             Section 3.5      Exchange of Certificates...............................................................13
             Section 3.6      Escrow Shares..........................................................................14
             Section 3.7      Dividends, Fractional Shares, Etc......................................................14
             Section 3.8      Tax Treatment..........................................................................16
             Section 3.9      Appraisal Rights.......................................................................16

ARTICLE IV. REPRESENTATIONS AND WARRANTIES OF RIVERBED...............................................................17
             Section 4.1      Organization and Qualifications; Subsidiaries..........................................17
             Section 4.2      Articles of Incorporation or Charter and Bylaws........................................17
             Section 4.3      Capitalization.........................................................................17
             Section 4.4      Authority Relative to This Agreement...................................................18
             Section 4.5      No Conflict; Required Filings and Consents; Certain Contracts..........................18
             Section 4.6      Financial Statements...................................................................19
             Section 4.7      Absence of Certain Changes or Events...................................................20
             Section 4.8      Conformity with Law; Relations with Governments; Litigation............................20
             Section 4.9      Employee Benefit Plans and Related Matters; ERISA......................................20
             Section 4.10     Labor and Employment Matters...........................................................23
             Section 4.11     Insurance..............................................................................23
             Section 4.12     Brokers................................................................................24
             Section 4.13     Taxes..................................................................................24
             Section 4.14     Environmental Matters..................................................................25
             Section 4.15     Intellectual Property..................................................................26
             Section 4.16     Books and Records......................................................................29
             Section 4.17     Transactions with Affiliates...........................................................29
</TABLE>

                                       i

<PAGE>   3

<TABLE>
<S>                           <C>                                                                                  <C>
             Section 4.18     Opinion of Financial Advisor...........................................................29
             Section 4.19     Reliance...............................................................................30
             Section 4.20     Disclosure.............................................................................30
             Section 4.21     Material Contracts.....................................................................30
             Section 4.22     Year 2000..............................................................................30
             Section 4.23     Distribution...........................................................................31
             Section 4.24     Real Property..........................................................................31
             Section 4.25     Personal Property......................................................................31

ARTICLE V. REPRESENTATIONS AND WARRANTIES OF AETHER AND MERGER SUB...................................................32
             Section 5.1      Organization and Qualifications; Subsidiaries..........................................32
             Section 5.2      Charter and Bylaws.....................................................................32
             Section 5.3      Capitalization.........................................................................32
             Section 5.4      Authority Relative to This Agreement...................................................33
             Section 5.5      No Conflict; Required Filings and Consents.............................................33
             Section 5.6      SEC Reports and Financial Statements...................................................34
             Section 5.7      Brokers................................................................................35
             Section 5.8      Conformity with Law; Relations with Governments; Litigation............................35
             Section 5.9      Transactions with Affiliates...........................................................35
             Section 5.10     Merger Sub.............................................................................35
             Section 5.11     Reliance...............................................................................35
             Section 5.12     Disclosure.............................................................................35
             Section 5.13     Absence of Changes.....................................................................36
             Section 5.14     Information Supplied...................................................................36

ARTICLE VI. COVENANTS................................................................................................37
             Section 6.1      Notification of Certain Matters........................................................37
             Section 6.2      Further Action, Reasonable Efforts; Consents and Approvals.............................37
             Section 6.3      Regulatory Filings.....................................................................37
             Section 6.4      Conduct of Business of Riverbed Pending the Closing....................................38
             Section 6.5      Conduct of Business of Aether Pending the Closing......................................40
             Section 6.6      Nasdaq Listing.........................................................................40
             Section 6.7      Access to Information..................................................................41
             Section 6.8      No Solicitation........................................................................41
             Section 6.9      Riverbed Stockholder Meeting...........................................................42
             Section 6.10     Preparation of the Disclosure Statements...............................................42
             Section 6.11     Cooperation with Accountants...........................................................43
             Section 6.12     Public Announcements...................................................................43
             Section 6.13     Blue Sky...............................................................................43
             Section 6.14     Registration Rights....................................................................43
             Section 6.15     General Indemnification................................................................44
             Section 6.16     Stockholder's Representative...........................................................44
             Section 6.17     Indemnification Procedures.............................................................45
</TABLE>
                                       ii
<PAGE>   4
<TABLE>
<S>                           <C>                                                                                  <C>
             Section 6.18     Exclusive Remedy.......................................................................47
             Section 6.19     Directors' and Officers' Indemnification and Insurance.................................48
             Section 6.20     Tax-Free Reorganization................................................................49
             Section 6.21     Board Representation...................................................................49
             Section 6.22     Notification of Certain Matters........................................................50

ARTICLE VII. CONDITIONS TO THE MERGER................................................................................51
             Section 7.1      Conditions to Each Party's Obligation to Effect the Merger.............................51
             Section 7.2      Conditions to Obligations of Riverbed to Effect the Merger.............................51
             Section 7.3      Conditions to Obligations of Aether and Merger Sub to Effect the Merger................52

ARTICLE VIII. TERMINATION, WAIVER, AMENDMENT AND CLOSING.............................................................54
             Section 8.1      Termination............................................................................54
             Section 8.2      Effect of Termination..................................................................55
             Section 8.3      Amendment or Supplement................................................................55
             Section 8.4      Extension of Time, Waiver, Etc.........................................................55
             Section 8.5      Termination Fee........................................................................56

ARTICLE IX. MISCELLANEOUS............................................................................................57
             Section 9.1      Governing Law..........................................................................57
             Section 9.2      Entire Agreement.......................................................................57
             Section 9.3      Modification; Waiver...................................................................57
             Section 9.4      Notices................................................................................57
             Section 9.5      Expenses...............................................................................59
             Section 9.6      Assignment.............................................................................59
             Section 9.7      Survival of Representations, Warranties and Covenants..................................59
             Section 9.8      Severability...........................................................................59
             Section 9.9      Successors and Assigns; Third Parties..................................................59
             Section 9.10     Counterparts...........................................................................59
             Section 9.11     Interpretation; References.............................................................60
             Section 9.12     Dispute Resolution and Jurisdiction....................................................60
             Section 9.13     Exhibits, Schedules and Disclosure Letter..............................................60
             Section 9.14     Attorneys' Fees........................................................................60
             Section 9.15     WAIVER OF JURY TRIAL...................................................................60
             Section 9.16     Further Assurances.....................................................................61
             Section 9.17     Negotiation of Agreement...............................................................61
</TABLE>


                                      iii

<PAGE>   5




                                    EXHIBITS
<TABLE>
<S>            <C>
Exhibit A --   [RESERVED]
Exhibit B --   Form of Legal Opinion of Wilmer, Cutler & Pickering, Counsel to
               Aether and Merger Sub
Exhibit C --   Form of Legal Opinion of Shaw Pittman, Counsel to Riverbed
Exhibit D --   Form of Registration Rights Agreement
Exhibit E --   Form of Voting Agreement
Exhibit F --   Form of Tax Representation Letters
Exhibit G --   Form of Escrow Agreement
Exhibit H --   Form of Employment Agreement
Exhibit I --   [RESERVED]
Exhibit J --   Form of Certificate of Incorporation of Surviving Corporation
Exhibit K --   Form of Bylaws of Surviving Corporation
Exhibit L --   Form of Confirmation and Non-Compete Agreement
</TABLE>
                                      iv
<PAGE>   6

                          AGREEMENT AND PLAN OF MERGER

       AGREEMENT AND PLAN OF MERGER, dated as of February 9, 2000 (the
"Agreement"), by and among AETHER SYSTEMS, INC., a Delaware corporation
("Aether"), RT ACQUISITION, INC., a Delaware corporation and a wholly-owned
direct subsidiary of Aether ("Merger Sub"), and RIVERBED TECHNOLOGIES, INC., a
Delaware corporation ("Riverbed").

       WHEREAS, Aether, Merger Sub and Riverbed have determined that the merger
of Merger Sub and Riverbed on the terms set forth herein (the "Merger") is
advisable and in the best interests of their respective corporations and
stockholders and their respective boards of directors have approved this
Agreement;

       WHEREAS, to satisfy a condition to Aether and Riverbed entering into this
Agreement and incurring the obligations set forth herein, concurrently with the
execution and delivery of this Agreement, Persons holding approximately 90% of
Riverbed's voting securities have entered into a Voting Agreement with Aether
and Riverbed pursuant to which they have each agreed, among other things, to
vote for the Merger and grant a proxy to officers of Aether with respect to the
Merger; and

       WHEREAS, by executing this Agreement, the parties intend to adopt a plan
of reorganization within the meaning of Section 368 of the Internal Revenue Code
of 1986, as amended.

       NOW, THEREFORE, in consideration of the mutual representations,
warranties and agreements contained herein and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto, intending to be legally bound hereby, agree as follows:

                                   ARTICLE I.

                                   DEFINITIONS

Section 1.1 Definitions. The capitalized terms used in this Agreement and not
otherwise defined shall have the following meanings (unless the context
otherwise requires, such capitalized terms shall include the singular and plural
and the conjunctive and disjunctive forms of the terms defined):

       "Acquisition Proposal" shall have the meaning set forth in Section 6.8.

       "Aether Common Stock" shall mean Common Stock, par value $.01 per share,
of Aether.

       "Aether Disclosure Letter" shall mean the letter dated as of the date of
this Agreement from Aether and Merger Sub to Riverbed and attaching the
schedules referred to in this Agreement.

                                                                               1
<PAGE>   7

       "Aether Indemnified Party" means Aether or any of its Subsidiaries as an
Indemnified Party.

       "Aether Option" shall mean an Option of Aether.

       "Aether SEC Reports" shall have the meaning set forth in Section 5.6.

       "Aether Stock Plans" shall have the meaning set forth in Section 5.3.

       "Affiliate" shall mean, as to any Person, any other Person
controlling, controlled by, or under common control with such Person.

       "Appraisal Shares" shall have the meaning set forth in Section 3.9.

       "Average Aether Stock Price" with respect to any period shall mean (i)
the sum of the daily closing sales prices per share of Aether Common Stock on
the Nasdaq National Market as reported in The Wall Street Journal (and confirmed
by the Aether Financial Advisor) for each of the Trading Days in the period
divided by (ii) the number of Trading Days in the period.

       "Benefit Arrangement" shall mean any benefit arrangement, obligation, or
practice, whether or not legally enforceable, to provide benefits (other than
merely as salary or under a Benefit Plan), as compensation for services
rendered, to present or former directors, employees, agents, or independent
contractors, including, but not limited to, employment or consulting agreements,
severance agreements or pay policies, executive or incentive compensation
programs or arrangements, sick leave, vacation pay, plant closing benefits,
salary continuation for disability, workers' compensation, retirement, deferred
compensation, bonus, stock option or purchase, tuition reimbursement or
scholarship programs, employee discount programs, meals, travel, or vehicle
allowances, any plans subject to Section 125 of the Code, and any plans
providing benefits or payments in the event of a change of control, change in
ownership or effective control, or sale of a substantial portion (including all
or substantially all) of the assets of any business or portion thereof, in each
case with respect to any present or former employees, directors, or agents.

       "Benefit Plan" shall mean an employee benefit plan as defined in Section
3(3) of ERISA, together with plans or arrangements that would be so defined if
they were not (i) otherwise exempt from ERISA by that or another section, (ii)
maintained outside the United States, or (iii) individually negotiated or
applicable only to one person.

       "Blue Sky Laws" shall mean the securities laws of the states of the
United States as currently in effect.

       "Business Day" shall mean any day other than a Saturday, a Sunday or a
day on which banking institutions in Baltimore, Maryland or New York City, New
York are not required to be open.

       "Certificate of Merger" shall have the meaning set forth in Section 2.2.

       "Certificate" shall have the meaning set forth in Section 3.4.



                                                                               2
<PAGE>   8

       "Claim Notice" shall have the meaning set forth in Section 6.17.

       "Claims" shall have the meaning set forth in Section 6.17.

       "Closing" shall have the meaning set forth in Section 2.3.

       "Closing Date" shall have the meaning set forth in Section 2.3.

       "COBRA" shall have the meaning set forth in Section 4.9.

       "Code" shall mean the Internal Revenue Code of 1986, as amended.

       "Confidential Information" shall have the meaning set forth in Section
6.7.

       "Confirmation and Non-Compete Agreement" means a confirmation and
non-compete agreement substantially in the form of Exhibit L.

       "Consents" shall have the meaning set forth in Section 6.2.

       "Contract" shall mean, with respect to any Person, any contract,
contractual right, note, bond, indenture, lease, license, permit, franchise,
deed of trust, mortgage, loan agreement or other document, instrument,
obligation or agreement, oral or written, to which such Person or any of its
Subsidiaries is a party or by which any of them or their assets or properties is
bound or affected.

       "Damages" shall have the meaning set forth in Section 6.15.

       "Date-Sensitive System" means any software programs, microcode, hardware,
system, device or component that processes (including, accepting as input,
sequencing, calculating, storing, displaying and generating as output any date
information or information from or dependent on date information, whether
performed on a stand-alone basis or in combination with any other software
program, microcode, hardware, system, device or component) any date information
and any data that is derived from or dependent on date information.

       "DGCL" means the General Corporation Law of the State of Delaware.

       "Disclosure Letter" shall mean the letter dated as of the date of this
Agreement from Riverbed to Aether and Merger Sub and attaching the schedules
referred to in this Agreement.

       "Effective Day" shall mean the day on which the Effective Time occurs.

       "Effective Time" shall have the meaning set forth in Section 2.2.

       "Employment Agreements" shall mean the employment agreements or
amendments to employment agreements between certain officers of Riverbed, as
identified by Aether, and Riverbed, Merger Sub and or Aether in substantially
the form of Exhibit H.

       "EPA" shall have the meaning set forth in Section 4.13.

                                                                               3
<PAGE>   9

       "ERISA" shall mean the Employee Retirement Income Security Act of 1974,
as amended, and all regulations and rules issued thereunder, or any successor
law.

       "ERISA Affiliate" shall mean any person or entity that, together with the
entity referenced, would be or was at any time treated as a single employer
under Code Section 414 or ERISA Section 4001 (including any entities excluded
from the definition because they are not subject to U.S. jurisdiction) and any
general partnership of which such entity is or has been a general partner.

       "Escrow Agent" shall mean Branch Bank & Trust Company, a North Carolina
banking association.

       "Escrow Agreement" shall mean the escrow agreement to be entered into by
the parties hereto, the Stockholders' Representative, and the Escrow Agent,
substantially in the form of Exhibit G.

       "Escrow Shares" shall have the meaning set forth in Section 3.6.

       "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended.

       "Exchange Agent" shall have the meaning set forth in Section 3.5.

       "GAAP" shall mean generally accepted accounting principles.

       "Governmental Authority" shall mean any government or any agency, bureau,
board, commission, court, judicial or quasi-judicial body, department,
authority, official, political subdivision, tribunal or other instrumentality of
any government, whether Federal, state or local, domestic or foreign.

       "HSR Act" shall have the meaning set forth in Section 4.5.

       "HSR Filings" shall have the meaning set forth in Section 6.3.

       "IRS" shall mean the United States Internal Revenue Service or any
successor agency.

       "Indemnified Officers/Directors" shall have the meaning set forth in
Section 6.19.

       "Indemnified Party" shall have the meaning set forth in Section 6.17.

       "Indemnifying Party" shall have the meaning set forth in Section 6.17.

       "Intellectual Property" means (i) all patents, trademarks, trade names,
service marks, trade dress, copyrights and any renewal rights therefor, mask
works, schematics, technology, inventions, manufacturing processes, supplier
lists, know-how (including trade secrets and other unpatented and/or
unpatentable proprietary or confidential information, systems or procedures),
moral rights, computer software programs or applications (in both source and
object code form), and all applications, renewals and registrations for any of
the foregoing; (ii) all software and firmware listings, and updated software
source code, and complete system build software and



                                                                               4
<PAGE>   10

instructions related to all software described herein; (iii) all documents,
records and files relating to design, end user documentation, manufacturing,
quality control, sales, marketing or customer support for all intellectual
property described herein; (iv) all other tangible or intangible proprietary
information and materials owned or held by or on behalf of the
intellectual-property holder.

       "Knowledge" shall mean, with respect to any party, the actual knowledge
of all directors or officers, including without limitation the Chief Executive
Officer, President, Secretary, Treasurer, Chief Financial Officer, Chief
Operating Officer, Comptroller, Chief Technology Officer, Assistant Secretary,
and any Senior Vice President of each such party as well as any knowledge of any
fact or circumstance that would have or should have come to the attention of any
such director or officer in the course of discharging his or her duties in a
reasonable and prudent manner consistent with sound business practices.

       "Law" shall mean any law, statute, rule, regulation, ordinance, decree or
order of any Governmental Authority.

       "Leases" shall have the meaning set forth in Section 4.24.

       "Letter of Transmittal" shall have the meaning set forth in Section 3.5.

       "Lien" shall mean any mortgage, pledge, assessment, security interest,
lease, sublease, lien, adverse claim, levy, charge, option, right of others or
restriction (whether on voting, sale, transfer, disposition or otherwise) or
other encumbrance of any kind, whether imposed by agreement, understanding, law
or equity, or any conditional sale contract, title retention contract or other
contract to give or to refrain from giving any of the foregoing.

       "Losses" shall have the meaning set forth in Section 6.19.

       "Material Adverse Effect" shall mean, with respect to any Person, a
material adverse effect on (i) the validity or enforceability of this Agreement,
(ii) the ability of such Person to perform its obligations under this Agreement
or (iii) the business, properties (including intangible properties), assets or
liabilities, prospects, financial condition or results of operations of the
Person and its Subsidiaries, taken as a whole other than (a) changes or effects
which are or result from occurrences relating to the economy in general or any
Person's industry in general and (x) not specifically relating to such Person or
(y) that affect such Person materially disproportionately relative to other
similarly-situated participants in such Person's industry, (b) changes or
effects which result from the loss of customers or delay or cancellation or
cessation of orders for any Person's products directly attributable to the
announcement of this Agreement provided that such losses, delays or
cancellations were not reasonably foreseeable to such Person as of the date of
this Agreement, (c) liabilities incurred in connection with this Agreement or
the transactions contemplated hereby, or (d) solely as a result of the decline
in the market price of the shares Aether Common Stock.

       "Material Contracts" shall have the meaning set forth in Section 4.21.

       "Measurement Period" means the period beginning on January 27, 2000
through and ending on the Trading Day that is the Trading Day prior to the date
of this Agreement



                                                                               5
<PAGE>   11

       "Merger" shall have the meaning set forth in the preamble to this
Agreement.

       "Merger Consideration" shall have the meaning set forth in Section 3.2.

       "Merger Filing" shall have the meaning set forth in Section 2.2.
"Multiemployer Plan" means any plan described in ERISA Section 3(37).

       "Nasdaq" means the Nasdaq Stock Market.

       "Notice Period" shall have the meaning set forth in Section 6.17.

       "Notices" shall have the meaning set forth in Section 9.4.

       "Option" shall mean, with respect to any Person, any option, warrant,
call, subscription, convertible or exchangeable security or other right,
agreement, arrangement or commitment of any kind or character to which such
Person or any of its Subsidiaries is a party relating to the issued or unissued
capital stock of such Person or any of its Subsidiaries, or obligating such
Person or any of its Subsidiaries to issue, transfer, grant or sell any shares
of capital stock of, or other equity interest in, or securities convertible into
or exchangeable for any capital stock or other equity interest in, such Person
or any of its Subsidiaries.

       "Option Exchange Ratio" shall have the meaning set forth in Section 3.3.

       "Organizational Documents" shall mean (i) with respect to a corporation
or association, its certificate or articles of incorporation or association and
bylaws, (ii) with respect to any limited liability company, its certificate of
formation, articles of organization, regulations, operating agreement and
limited liability company agreement, as applicable, (iii) with respect to any
limited partnership, its certificate of limited partnership and limited
partnership agreement, (iv) with respect to any general partnership, its
partnership agreement, and (v) all other similar organizational documents.

       "Palm Computing Contracts" means the Joint Development & Distribution
Agreement dated September 1, 1999 by and between Riverbed and Palm Computing,
Inc., a subsidiary of 3Com Corporation, and the Reseller Agreement dated
September 1, 1999 by and between Riverbed and Palm Computing, Inc., a subsidiary
of 3Com Corporation.

       "Permitted Liens" shall mean (a) Liens for taxes, assessments, or similar
charges, incurred in the ordinary course of business that are not yet due and
payable; (b) pledges or deposits made in the ordinary course of business; (c)
Liens of mechanics, materialmen, warehousemen or other like Liens securing
obligations incurred in the ordinary course of business that are not yet due and
payable; and (d) similar Liens and encumbrances which are incurred in the
ordinary course of business and which do not in the aggregate materially detract
from the value of such assets or properties or materially impair the use thereof
in the operation of such business.

       "Person" shall mean any natural person, corporation, general partnership,
limited partnership, limited liability company, limited liability partnership,
proprietorship, trust, union,



                                       6
<PAGE>   12

association, court, tribunal, agency, government, department, commission,
self-regulatory organization, arbitrator, board, bureau, instrumentality or
other entity, enterprise, authority or business organization.

       "Qualified Plan" shall mean any Riverbed Plan intended to meet the
requirements of Section 401(a) of the Code, including any previously terminated
plan.

       "Real Property" shall have the meaning set forth in Section 4.24.

       "Registration Rights Agreement" means a registration rights agreement
substantially in the form of Exhibit D.

       "Related Employer" means Riverbed and every ERISA Affiliate.

       "Representatives" means, with respect to any Person, the officers,
directors, employees, auditors and other agents and representatives of such
Person.

       "Requisite Regulatory Approvals" shall have the meaning set forth in
Section 4.5.

       "Riverbed Benefit Arrangement" shall mean any Benefit Arrangement any
Related Employer sponsors or maintains or with respect to which any Related
Employer has or may have any current or future liability (whether actual,
contingent, with respect to any of its assets or otherwise), in each case with
respect to any present or former service providers to any Related Employer.

       "Riverbed Capital Stock" shall mean the Riverbed Common Stock, Riverbed
Preferred Stock, and any other capital stock of Riverbed other than Riverbed
Options.

       "Riverbed Common Stock" shall mean the common stock, par value $.01 per
share, of Riverbed.

       "Riverbed Companies" shall mean Riverbed and any subsidiary of Riverbed
that currently has or previously had employees.

       "Riverbed Financial Advisor" shall have the meaning set forth in Section
4.11.

       "Riverbed Indemnified Party" means Riverbed or any of its Subsidiaries or
its stockholders as an Indemnified Party.

       "Riverbed Intellectual Property" means all Intellectual Property, other
than Third Party Intellectual Property, that is being, has been, or is
reasonably anticipated by Riverbed to be, used, or is currently under
development for use, in the business of Riverbed or its Subsidiaries.

       "Riverbed Meeting" shall have the meaning set forth in Section 6.9.

       "Riverbed Option" shall mean an Option of Riverbed.

       "Riverbed Plan" shall mean any Benefit Plan that any Related Employer
maintains or has maintained or to which any Related Employer is obligated to
make payments or has or may have

                                                                               7
<PAGE>   13

any liability, in each case with respect to any present or former employees of
any Related Employer.


       "Riverbed Preferred Stock" shall mean the Series A and the Series B
preferred stock of Riverbed convertible into Riverbed Common Stock.

       "Riverbed Third Party Consents" shall have the meaning set forth in
Section 4.21.

       "Riverbed Stockholder Approval" shall have the meaning set forth in
Section 6.9.

       "SEC" shall mean the Securities and Exchange Commission or any successor
commission.

       "Securities Act" shall mean the Securities Act of 1933, as amended.

       "Stockholder Representative" shall mean Hooks Johnston and Phil Herget.

       "Subsidiary" of an entity shall mean any entity (i) required by GAAP to
be consolidated in the financial statements of such entity or (ii) over 50% of
whose voting securities are controlled directly or indirectly by a single
entity.

       "Surviving Corporation" shall have the meaning set forth in Section 2.1.

       "Tax" or "Taxes" shall mean all Federal, state, local and foreign taxes
and other assessments and governmental charges of a similar nature (whether
imposed directly or through withholdings), including any interest, penalties and
additions to tax applicable thereto.

       "Tax Returns" shall mean all Federal, state, local and foreign returns,
declarations, statements, reports, schedules, forms and information returns
relating to Taxes, and all amendments thereto.

       "Third Party Intellectual Property" means all Intellectual Property owned
by or on behalf of persons other than Riverbed or its Subsidiaries that is
being, has been, or is reasonably anticipated by Riverbed to be, used, or is
currently under development for use, in the business of Riverbed or its
Subsidiaries.

       "Trading Day" shall mean a day on which Aether Common Stock is traded on
the Nasdaq.

       "Transactions" shall mean the transactions contemplated by this Agreement
in ARTICLE II.

       "Voting Agreement" means a voting agreement substantially in the form of
Exhibit E.

       "Year 2000 Compliant" means: (i) with respect to date information and any
data that are derived from or dependent on date information, that such date
information and data are in proper format and unambiguous for all dates before,
on or after January 1, 2000 (including taking into account leap year
considerations); and (ii) with respect to Date-Sensitive Systems, that each such


                                                                               8
<PAGE>   14

Date-Sensitive System correctly processes all date information and any data that
are derived from or dependent on date information for all dates before, on or
after January 1, 2000 (including taking into account leap year considerations)
without any loss of functionality, interoperability or performance, and whether
used on a stand-alone basis or in combination with any other software,
microcode, hardware, system, device or component, assuming, in each case, that
each item of date information and data derived from or dependant on date
information that is passed to the Date-Sensitive System by any other software,
microcode, hardware, system, device or component is Year 2000 Compliant.




                                                                               9
<PAGE>   15


                                  ARTICLE II.

                                   THE MERGER

       Section 2.1 The Merger. Upon the terms and subject to the conditions of
this Agreement, at the Effective Time, in accordance with the DGCL, Merger Sub
shall be merged with and into Riverbed in accordance with this Agreement and the
separate existence of Merger Sub shall cease. Riverbed shall be the surviving
corporation in the Merger (hereinafter sometimes referred to as the "Surviving
Corporation").

       Section 2.2 Effective Time of the Merger. Upon the terms and subject to
the conditions hereof, a certificate of merger (the "Certificate of Merger")
shall be duly prepared, executed and acknowledged by the Surviving Corporation
and thereafter delivered to the Secretary of State of the State of Delaware, for
filing on the Closing Date (as defined in Section 2.3). The Merger shall become
effective as of the date and at such time as the Certificate of Merger pursuant
to Section 252 of the DGCL and any other documents necessary to effect the
Merger in accordance with the DGCL are duly filed (the "Merger Filing") with the
Secretary of State of the State of Delaware or at such subsequent date or time
as shall be agreed by Aether and Riverbed and specified in the Certificate of
Merger (the time the Merger becomes effective pursuant to the DGCL being
referred to herein as the "Effective Time").

       Section 2.3 Closing. Subject to the satisfaction or waiver of all of the
conditions to closing contained in ARTICLE VII, the closing of the Merger (the
"Closing") will take place at such time and such date as specified by the
parties, which shall be no later than the first Business Day after the
satisfaction or waiver of the conditions to Closing contained in ARTICLE VII, at
the offices of Wilmer, Cutler & Pickering, 2445 M Street, NW, Washington, D.C.
20037, unless another date, time or place is agreed to in writing by the parties
hereto. The date and time at which the Closing occurs is referred to herein as
the "Closing Date."

       Section 2.4 Effects of the Merger. The Merger shall have the effects set
forth in the DGCL. Without limiting the generality of the foregoing, and subject
thereto, at the Effective Time, all the properties, rights, privileges, powers
and franchises of Riverbed and Merger Sub shall vest in the Surviving
Corporation, and all debts, liabilities and duties of Riverbed and Merger Sub
shall become the debts, liabilities and duties of the Surviving Corporation.

       Section 2.5 Certificate of Incorporation and Bylaws. Subject to Section
6.19, the Certificate of Incorporation of the Surviving Corporation shall be in
the form set forth in Exhibit J to this Agreement. The Bylaws of the Surviving
Corporation shall be in substantially the form set forth in Exhibit K to this
Agreement.



                                                                              10
<PAGE>   16

       Section 2.6 Directors of the Surviving Corporation. The directors of the
Surviving Corporation shall be as set forth on Schedule 2.6 to the Aether
Disclosure Letter, each to hold office from the Effective Time in accordance
with the Certificate of Incorporation and Bylaws of the Surviving Corporation
and until his or her successor is duly elected and qualified.

       Section 2.7 Officers of the Surviving Corporation. The officers of the
Surviving Corporation shall be as set forth on Schedule 2.7 to the Aether
Disclosure Letter, each to hold office from the Effective Time in accordance
with the Certificate of Incorporation and Bylaws of the Surviving Corporation
and until his or her successor is duly appointed and qualified.




                                                                              11
<PAGE>   17






                                  ARTICLE III.

                            CONVERSION OF SECURITIES

       Section 3.1 Conversion of Capital Stock of Merger Sub. At the Effective
Time, each issued and outstanding share of common stock, par value $0.01 per
share, of Merger Sub shall be converted into and become one fully paid and
nonassessable share of common stock, par value $0.01 per share, of the Surviving
Corporation.

       Section 3.2 Conversion of Riverbed Capital Stock.

       (a)    Except as otherwise provided in Section 3.4(b), Section 3.6, and
Section 3.9, at the Effective Time, each issued and outstanding share of
Riverbed Capital Stock shall be converted into the right to receive in the case
of each share of Riverbed Common Stock, 0.4221 (such number, as adjusted in
accordance with Section 3.7(g) the "Exchange Ratio"), of a validly issued, fully
paid and nonassessable share of Aether Common Stock, provided that the foregoing
Exchange Ratio assumes the conversion into Riverbed Common Stock of all issued
and outstanding shares of Riverbed Preferred Stock prior to Closing. The shares
of Aether Common Stock to be issued to a particular holder of shares of Riverbed
Capital Stock under this conversion formula shall be referred to as such
holder's "Merger Consideration."

       Section 3.3 Conversion of Riverbed Options.

       (a)    Subject to Section 3.4(b) and Section 3.9, at the Effective Time,
each issued and outstanding Riverbed Option shall be converted into the right to
receive an Aether Option, with terms and conditions substantially similar to the
Riverbed Option, except that (i) each such Riverbed Option will be exercisable
for that number of whole shares (and no fractional shares, for which cash shall
be paid pursuant to Section 3.7(b)) of Aether Common Stock equal to the product
of the number of shares of Riverbed Common Stock that were issuable upon the
exercise of such Riverbed Stock Option multiplied by 0.4221 (the "Option
Exchange Ratio") and (ii) the per share exercise price for the shares of Aether
Common Stock issuable upon the exercise of such Riverbed Stock Option will be
equal to the quotient determined by dividing the exercise price per share of
Riverbed Common Stock at which such Riverbed Stock Option would have been
exercisable immediately prior to the Effective Time by the Option Exchange
Ratio, rounded up to the nearest whole cent; provided, however, that the
foregoing conversions would be adjusted with respect to Options that qualify as
incentive stock options under Section 422 of the Code to the extent necessary to
preserve their treatment as such.

       Section 3.4 General Conversion Mechanics.

       (a)    As a result of the Merger and without any action on the part of
the holders thereof, at the Effective Time, all shares of Riverbed Capital Stock
shall no longer be outstanding and shall automatically be cancelled and retired
and shall cease to exist, and each holder of shares of Riverbed Capital Stock
shall thereafter cease to have any rights with respect to such shares of
Riverbed Capital Stock, except (i) the right to receive, without interest, the

                                                                              12
<PAGE>   18

Merger Consideration and cash for fractional shares of Aether Capital Stock in
accordance with Section 3.2 upon the surrender of a certificate that,
immediately prior to the Effective Time, represented an outstanding share or
shares of Riverbed Capital Stock (a "Certificate"); or (ii) the appraisal rights
described in Section 3.9.

       (b)    Notwithstanding anything contained in this ARTICLE III to the
contrary, each share of Riverbed Capital Stock issued and held in Riverbed's
treasury or by a wholly-owned Subsidiary of Riverbed immediately prior to the
Effective Time, and each share of Riverbed Capital Stock or Option owned by
Aether or Merger Sub at or immediately prior to the Effective Time, if any,
shall, by virtue of the Merger, cease to be outstanding and shall be cancelled
and retired and shall cease to exist without payment of any consideration
therefor.

       Section 3.5 Exchange of Certificates.

       (a)    Except as provided in Section 3.5(e) below, upon the Closing,
Aether shall irrevocably deposit (or cause to be deposited) with Bank Boston,
N.A. (the "Exchange Agent"), for the benefit of the holders of shares of
Riverbed Capital Stock, for exchange in accordance with this ARTICLE III, (i)
cash in lieu of fractional shares and (ii) certificates representing the
aggregate number of shares of Aether Common Stock that may be issued to pay the
stock portion of the Merger Consideration less the Escrow Shares and the shares
of Aether Common Stock delivered at Closing pursuant to Section 3.5(e) below.
Aether Common Stock into which Riverbed Capital Stock shall be converted
pursuant to the Merger shall be deemed to have been issued at the Effective
Time.

       (b)    Within ten (10) Business Days after the Effective Time, Aether
shall cause the Exchange Agent to mail to each holder of record of Riverbed
Capital Stock immediately prior to the Effective Time (excluding any Appraisal
Shares) (i) a letter of transmittal (which shall specify that delivery shall be
effected, and risk of loss and title to the Certificates shall pass, only upon
delivery of the Certificates to the Exchange Agent), which shall be in customary
form with such customary provisions as Aether shall reasonably specify (the
"Letter of Transmittal") and (ii) instructions for use in effecting the
surrender of the Certificates in exchange for the Merger Consideration.

       (c)    Upon surrender of a Certificate, in such form and with such
endorsements, stock powers and signature guaranties as may be required by the
Letter of Transmittal for cancellation to the Exchange Agent or to such other
agent or agents as may be appointed by Aether, together with the Letter of
Transmittal, duly executed, and such other documents as Aether or the Exchange
Agent shall reasonably request, the holder of such Certificate shall be entitled
to receive in exchange therefor promptly after the Effective Time, (i) a check
in an amount equal to the cash which such holder has the right to receive
pursuant to the provisions of this ARTICLE III and (ii) a certificate
representing the number of shares of Aether Common Stock which such holder has
the right to receive pursuant to the provisions of this ARTICLE III (in each
case, less the amount of any required withholding taxes), and the Certificate so
surrendered shall forthwith be cancelled. Until surrendered as contemplated by
this Section 3.5(c), each Certificate shall be deemed at any time after the
Effective Time to represent only the right to receive the Merger Consideration
with respect to the shares of Riverbed Capital Stock formerly represented
thereby.



                                                                              13
<PAGE>   19

       (d)    Aether and the Stockholder's Representative shall jointly have the
right to make rules, not inconsistent with the terms of this Agreement,
governing the issuance and delivery of the certificates for Aether Common Stock
into which shares of Riverbed Capital Stock are converted in the Merger, and the
payment of cash for shares of Riverbed Capital Stock converted in the Merger.

       (e)    Unless the Exchange Agent notifies Aether and the Stockholder's
Representative in writing that it will not be necessary for certain Riverbed
stockholders to attend the Closing (the "Attending Stockholders") in order to
participate in the registered offering contemplated by Section 6.14, Aether
shall deliver at the Closing the Merger Consideration that would have otherwise
been deposited with the Exchange Agent pursuant to Section 3.5(a) for the
benefit of such stockholders. Such notice shall be delivered at least three days
prior to the expected Closing Date, shall state the name of each attending
stockholder and shall set forth the number of shares of Aether Common Stock to
be issued to such attending stockholder. At the Closing, upon surrender to
Aether of a Certificate by an Attending Stockholder for cancellation, together
with any other documents reasonably required by Aether, the Attending
Stockholder shall receive (i) a check in an amount equal to the cash which such
holder has the right to receive pursuant to the provisions of this ARTICLE III
and (ii) a certificate representing the number of shares of Aether Common Stock
which such holder has the right to receive pursuant to the provisions of this
ARTICLE III. Aether and the Stockholders' Representative shall enter into a
mutually agreeable Exchange Agent Agreement.

       Section 3.6 Escrow Shares. The "Escrow Shares" shall mean an aggregate of
270,000 shares of Aether Common Stock comprising a portion of the Merger
Consideration payable to the holders of Riverbed Capital Stock. A pro rata
portion of the Escrow Shares shall be withheld from each person who is a
stockholder of Riverbed immediately before the Effective Time and deposited by
Aether at the Closing with the Escrow Agent pursuant to an Escrow Agreement in
the form of Exhibit E.

       Section 3.7 Dividends, Fractional Shares, Etc.

       (a)    Notwithstanding any other provisions of this Agreement, no
dividends or other distributions declared after the Effective Time on Aether
Common Stock shall be paid to the holder of any unsurrendered Certificates until
such Certificates are surrendered for exchange as provided in this ARTICLE III.
Subject to the effect of applicable laws, following the surrender of any such
Certificate, there shall be paid, without interest, to the Person in whose name
the certificates representing the shares of Aether Common Stock into which the
shares of Riverbed Capital Stock formerly represented by such Certificate were
converted are registered, (i) at the time of such surrender, the amount of all
dividends and other distributions with a record date after the Effective Time
theretofore payable with respect to such whole shares of Aether Common Stock and
not paid, less the amount of any withholding taxes which may be required
thereon, and (ii) at the appropriate payment date, the amount of dividends or
other distributions with a record date after the Effective Time but prior to
surrender and a payment date subsequent to surrender payable with respect to
such whole shares of Aether Common Stock, less the amount of any withholding
taxes which may be required thereon.



                                                                              14
<PAGE>   20

       (b)    No fractional shares of Aether Common Stock or Aether Options
shall be issued in the Merger. All fractional shares of Aether Common Stock or
Aether Options that a holder of shares of Riverbed Capital Stock or Riverbed
Options would otherwise be entitled to receive as a result of the Merger shall
be aggregated and, if a fractional share results from such aggregation, such
holder shall be entitled to receive, in lieu thereof, an amount in cash
determined by multiplying (i) the fraction of a share of Aether Common Stock to
which such holder would otherwise have been entitled (net any exercise price, if
applicable) by (ii) the Average Aether Stock Price for the Measurement Period.
No interest will be paid or will accrue on any cash paid or payable in lieu of
any fractional shares of Aether Common Stock or of an Aether Option.

       (c)    At and after the Effective Time, there shall be no further
registration of transfers of shares of Riverbed Capital Stock. If, after the
Effective Time, Certificates are presented to the Surviving Corporation, they
shall be cancelled and exchanged for the Merger Consideration in accordance with
the procedures set forth in this ARTICLE III.

       (d)    If any portion of the Merger Consideration is to be paid to a
Person other than the registered holder of the shares of Riverbed Capital Stock
represented by the Certificate or Certificates surrendered in exchange therefor,
it shall be a condition to such payment that the Certificate or Certificates so
surrendered shall be properly endorsed or otherwise be in proper form for
transfer and that the Person requesting such payment shall pay to the Exchange
Agent any transfer or other taxes required as a result of such payment to a
Person other than the registered holder of such Certificates or establish to the
satisfaction of the Exchange Agent that such tax has been paid or is not
payable.

       (e)    Any portion of the Merger Consideration or cash payable in lieu of
fractional shares made available to the Exchange Agent pursuant to this ARTICLE
III that remains unclaimed by the former holders of shares of Riverbed Capital
Stock one year after the Effective Time shall be delivered to Aether. Any such
holder who has not theretofore exchanged his Certificates for the Merger
Consideration in accordance with this ARTICLE III shall thereafter look only to
Aether for payment of the applicable Merger Consideration, cash in lieu of
fractional shares and unpaid dividends and distributions on the Aether Common
Stock deliverable in respect thereof, determined pursuant to this Agreement, in
each case, without interest. None of Aether, Riverbed or the Surviving
Corporation shall be liable to any former holder of shares of Riverbed Capital
Stock for any amount paid to a Governmental Authority pursuant to any applicable
abandoned property, escheat or similar laws. Any amounts remaining unclaimed by
holders of Certificates five years after the Effective Time (or such earlier
date immediately prior to such time as such amounts would otherwise escheat to
or become the property of any Governmental Authority) shall, to the extent
permitted by applicable law, become the property of Aether free and clear of any
claims or interest of any person previously entitled thereto.

       (f)    In the event that any Certificate shall have been lost, stolen or
destroyed, upon the making of an affidavit of that fact by the Person claiming
such Certificate to be lost, stolen or destroyed and, if required by Aether, the
posting by such Person of a bond in a customary amount as indemnity against any
claim that may be made against it with respect to such Certificate, the Exchange
Agent will issue in exchange for such lost, stolen or destroyed Certificate the
applicable Merger Consideration, cash in lieu of fractional shares, and unpaid


                                                                              15
<PAGE>   21

dividends and distributions on shares of Aether Common Stock deliverable in
respect thereof pursuant to this Agreement.

       (g)    If at any time during the period between the date of this
Agreement and the Effective Time, any change in the outstanding shares of
capital stock of Aether shall occur, including by reason of any
reclassification, reorganization, recapitalization, stock split or combination,
exchange or readjustment of shares, or any stock dividend thereon with a record
date during such period, the number of shares of Aether Common Stock
constituting all or part of the Merger Consideration shall be appropriately
adjusted in accordance with such change.

       Section 3.8 Tax Treatment. It is intended by the parties hereto that the
Merger shall constitute a reorganization within the meaning of Section
368(a)(2)(E) of the Code. The parties hereto adopt this Agreement as a "plan of
reorganization" within the meaning of Sections 1.368-2(g) and 1.368-3(a) of the
United States Income Tax Regulations.

       Section 3.9 Appraisal Rights. Riverbed Capital Stock which is not voted
in favor of the Merger and with respect to which a demand for appraisal shall
have been properly made in the manner provided by the DGCL ("Appraisal Shares")
shall not be converted into the right to receive any Merger Consideration and
the holders of Appraisal Shares shall be entitled only to such rights as are
contemplated by the DGCL; provided, however, that if a holder of Appraisal
Shares shall withdraw his, her or its demand for such payment or shall become
ineligible for such payment, pursuant to the DGCL, then as of the Effective Time
or the occurrence of such event of withdrawal or ineligibility, whichever later
occurs, such holder's Appraisal Shares shall cease to be Appraisal Shares and
shall be converted into the right to receive the applicable Merger
Consideration. Riverbed shall give Aether prompt notice of any Appraisal Shares
(and shall also give Aether prompt notice of any withdrawals of such demands for
appraisal rights) and Aether shall have the right to direct all negotiations and
proceedings with respect to any such demands. Riverbed shall not, except with
the prior written consent of Aether, voluntarily make any payment with respect
to, or settle or offer to settle, any such demand for appraisal rights.




                                       16
<PAGE>   22





                                  ARTICLE IV.

                   REPRESENTATIONS AND WARRANTIES OF RIVERBED

       Riverbed hereby represents and warrants to Aether and Merger Sub that:

       Section 4.1 Organization and Qualifications; Subsidiaries. Riverbed and
each Subsidiary of Riverbed is a corporation, partnership, or other legal entity
duly organized, validly existing and in good standing under the laws of the
jurisdiction of its incorporation or organization and has the corporate or other
applicable power and authority to own, lease and operate its properties and to
carry on its business as it is now being conducted. Each of Riverbed and its
Subsidiaries is duly qualified or licensed as a foreign corporation or
partnership to transact business, and is in good standing, in each jurisdiction
where the character of the properties owned, leased or operated by it or the
nature of its business makes such qualification or licensing necessary, except
where the failure to so qualify or be licensed would not have a Material Adverse
Effect.

       Section 4.2 Articles of Incorporation or Charter and Bylaws. Complete and
correct copies of the articles of incorporation or charter and bylaws of
Riverbed and each of its Subsidiaries, as amended to date, are included with
Schedule 4.2 to the Disclosure Letter. Such Organizational Documents are in full
force and effect and reflect all amendments or modifications adopted as of the
date hereof. Riverbed is not in violation of any provision of its Organizational
Documents. No Subsidiary of Riverbed is in violation of any provision of its
Organizational Documents.

       Section 4.3 Capitalization. The authorized capital stock of Riverbed
consists of (i) 14,354,789 shares of common stock, $.01 par value, of which (A)
3,104,129 shares are issued and outstanding, (B) 75,000 shares are reserved to
be issued upon exercise of Options to be granted to Riverbed management with a
minimum exercise price of $13.53 per share, and (C) Options to purchase
1,968,309 shares of Riverbed Common Stock are issued and outstanding, (ii)
3,500,000 shares of series A preferred stock, $.01 par value, of which 3,500,000
shares are issued and outstanding, and (iii) 4,145,211 shares of series B
preferred stock, $.01 par value, of which 4,145,211 shares are issued and
outstanding. All of the issued and outstanding shares of Riverbed Capital Stock
and the capital stock of each Subsidiary of Riverbed have been duly authorized
and validly issued and are fully paid and nonassessable and, with respect to
each Subsidiary, all shares of such capital stock are owned by Riverbed free and
clear of any Liens. All of the issued and outstanding shares of Riverbed Capital
Stock and of the capital stock of each Subsidiary of Riverbed were offered,
issued, sold and delivered by Riverbed in compliance with all applicable state
and federal laws concerning the issuance of securities. Further, none of such
shares was issued in violation of any preemptive rights. Except as set forth in
Schedule 4.3 to the Disclosure Letter, there are no voting agreements or voting
trusts with respect to any of the outstanding shares of Riverbed Capital Stock.
Since December 31, 1999, no shares of capital stock or other voting securities
of Riverbed or any of its Subsidiaries, or Options in respect thereof have been
issued except upon the exercise of Riverbed Options or the conversion of the
Riverbed Preferred Stock. Except for the Riverbed Options set forth in Schedule
4.3 of the



                                                                              17
<PAGE>   23

Disclosure Letter, there are not now, and at the Closing there will not be, any
Options of Riverbed in existence. All shares of Riverbed Capital Stock subject
to issuance as aforesaid, upon issuance on the terms and conditions specified in
the instruments pursuant to which they are issuable, will be duly authorized,
validly issued, fully paid and nonassessable. Except as set forth in Schedule
4.3 to the Disclosure Letter, there are no outstanding contractual obligations
of Riverbed or any of its Subsidiaries to repurchase, redeem or otherwise
acquire any shares of Riverbed Capital Stock or any other shares of capital
stock of Riverbed or any of its Subsidiaries, or make any material investment
(in the form of a loan, capital contribution or otherwise) in any Subsidiary of
Riverbed or any other Person, other than a wholly-owned Subsidiary of Riverbed
or a Person wholly-owned by one or more wholly-owned Subsidiaries of Riverbed.
Schedule 4.3 to the Disclosure Letter sets forth a complete listing as of
February 8, 2000 of holders of shares of Riverbed Capital Stock and holders of
Options to acquire Riverbed Capital Stock and the number of shares and Options
held by each.

       Section 4.4 Authority Relative to This Agreement. Riverbed has all
necessary corporate power and authority to execute and deliver this Agreement,
and, subject to the Riverbed Stockholder Approval, to perform its obligations
hereunder and to consummate the Transactions. The execution and delivery of this
Agreement by Riverbed, the performance by Riverbed of its obligations hereunder
and the consummation by Riverbed of the Transactions have been duly and validly
approved by the Board of Directors of Riverbed, the Board of Directors of
Riverbed has recommended approval of this Agreement by the stockholders of
Riverbed and directed that this Agreement be submitted to the stockholders of
Riverbed for their consideration, and no other corporate proceedings on the part
of Riverbed are necessary to authorize this Agreement or to consummate the
Transactions (other than the Riverbed Stockholder Approval and the Merger
Filing). This Agreement has been duly and validly executed and delivered by
Riverbed and, assuming the due authorization, execution and delivery thereof by
Aether and Merger Sub, constitutes the legal, valid and binding obligation of
Riverbed, enforceable against Riverbed in accordance with its terms, except as
enforceability may be limited by bankruptcy or other similar laws and general
principles of equity.

       Section 4.5 No Conflict; Required Filings and Consents; Certain
Contracts.

       (a)    The execution and delivery of this Agreement by Riverbed does not,
and the performance of its obligations under this Agreement and the consummation
of the Transactions by Riverbed will not, (i) conflict with, result in a breach
of, cause a dissolution or require the consent or approval of any Person under,
or violate any provision of, the Organizational Documents of Riverbed or any of
its Subsidiaries, (ii) require any consent, approval, authorization or permit
of, or filing with or notification to, any Governmental Authority, except for
(A) applicable requirements of the Hart-Scott-Rodino Antitrust Improvements Act
of 1976 (as amended, the "HSR Act"), including any rules and regulations
promulgated thereunder, (B) the Merger Filing, (C) the Riverbed Stockholder
Approval, and (D) such other consents, authorizations, filings, approvals and
registrations which if not obtained or made would not result in a Material
Adverse Effect on Riverbed or Aether, (iii) subject to the making of the filings
and obtaining the approvals identified in clause (ii), conflict with or violate
any Law, order, judgment, rule, regulation, ordinance, writ, injunction or
decree applicable to Riverbed or any of its Subsidiaries or by which any
property or asset of Riverbed or any Subsidiary is bound or affected, which
conflict or violation would result in a Material Adverse Effect on Riverbed or

                                       18
<PAGE>   24

the Surviving Corporation, or (iv) except as set forth in Schedule 4.5 of the
Disclosure Letter, conflict with or result in any breach of or constitute a
default (or an event which with notice or lapse of time or both would become a
default) under, result in the loss by Riverbed or any of its Subsidiaries or
modification in a manner materially adverse to Riverbed or any of its
Subsidiaries of any right or benefit under, or give to others any right of
termination, amendment, acceleration, repurchase or repayment, increased
payments or cancellation of, or result in the creation of a Lien or other
encumbrance on any Riverbed Capital Stock or any material property or asset of
Riverbed or any Subsidiary of Riverbed pursuant to, any Contract of Riverbed,
except, in each case, such as would not, individually or in the aggregate have a
Material Adverse Effect on Riverbed. The notices, consents or approvals, filings
or registrations, and expirations or terminations of waiting periods referred to
in clauses (A)-(C) above are hereinafter referred to as the "Requisite
Regulatory Approvals."

       (b)    Except as set forth in Schedule 4.5 of the Disclosure Letter,
there are no Contracts to which Riverbed or any Subsidiary of Riverbed is a
party or by which Riverbed or any Subsidiary of Riverbed or any asset of
Riverbed or any Subsidiary of Riverbed is bound, which by its terms materially
limits the ability of Riverbed or any Subsidiary of Riverbed, or after
consummation of the Transactions, would by its terms materially limit the
ability of Aether or any of its Affiliates, to engage in any business in any
area or for any period.

       Section 4.6 Financial Statements.

       (a)    The consolidated financial statements of Riverbed and its
Subsidiaries for the years ended December 31, 1998 and December 31, 1999, (the
"Financial Statements") included as Schedule 4.6(a) to the Disclosure Letter
hereto, were prepared in accordance with GAAP applied on a basis consistent with
prior periods and fairly present in all material respects except for necessary
normal recurring year end adjustments the consolidated financial position of
Riverbed and its consolidated Subsidiaries as at the dates thereof and the
consolidated results of their operations and cash flows for the respective
periods then ended and do not contain any material misstatements of the
financial condition or results of operations of Riverbed at such dates or for
the periods then ended.

       (b)    Since December 31, 1999, neither Riverbed nor any of its
Subsidiaries has incurred any liabilities or obligations (whether absolute,
accrued, fixed, contingent, liquidated, unliquidated or otherwise and whether
due or to become due) of any nature, except as set forth in Schedule 4.6(b) to
the Disclosure Letter and except liabilities, obligations or contingencies (i)
which were incurred after December 31, 1999 in the ordinary course of business
consistent with past practices under any contract, commitment or agreement
specifically disclosed in a Schedule to the Disclosure Letter or not required to
be disclosed thereon because of the term or amount involved or otherwise, (ii)
which were incurred as a result of the Transactions contemplated by this
Agreement, (iii) which were disclosed or reserved against on the balance sheet
to the Financial Statements or which would not be required under GAAP to be
reported on the balance sheet to the Financial Statements, or (iv) which would
not reasonably be expected to have, individually or in the aggregate, a Material
Adverse Effect on Riverbed. Riverbed and its Subsidiaries have timely filed all
forms, reports and other documents material to the business of Riverbed and its
Subsidiaries required to be filed prior to the date hereof with any Governmental
Authority.



                                                                              19
<PAGE>   25

       (c)    Since December 31, 1998, there has been no change in any of the
significant accounting (including Tax accounting) policies, practices or
procedures of Riverbed or any Subsidiary of Riverbed, except changes to comply
with changes in accounting pronouncements of the Financial Accounting Standards
Board or changes in applicable laws or rules or regulations thereunder as
disclosed on Schedule 4.6(c) to the Disclosure Letter.

       Section 4.7 Absence of Certain Changes or Events. Except as a result of
this Agreement and the transactions contemplated hereby or as set forth in
Schedule 4.7 to the Disclosure Letter, since December 31, 1999, (a) each of
Riverbed and its Subsidiaries has conducted its respective business only in the
ordinary course consistent with past practices, and has not taken any of the
actions set forth in paragraphs (a) through (l) of Section 6.4 and (b) there has
not occurred or arisen any event that, individually or in the aggregate, has had
or, insofar as can be reasonably foreseen, would have a Material Adverse Effect
on Riverbed or any of its Subsidiaries.

       Section 4.8 Conformity with Law; Relations with Governments; Litigation.
Each of Riverbed and its Subsidiaries has not violated any law or regulation or
any order of any Governmental Authority having jurisdiction over it which would
have a Material Adverse Effect. Riverbed has not offered anything of value to
any governmental official, political party or candidate for government office
nor has it otherwise taken any action that would cause Riverbed to be in
violation of the Foreign Corrupt Practices Act of 1977, as amended, or any law
of similar effect. Schedule 4.8 to the Disclosure Letter lists, as of the date
hereof and the Closing Date, all claims, suits, actions or proceedings pending
or, to the Knowledge of each of Riverbed and its Subsidiaries, threatened or
contemplated, including any investigations or reviews by any Governmental
Authority pending or, to the Knowledge of each of Riverbed and its Subsidiaries,
threatened or contemplated, against, relating to or affecting each of Riverbed
and its Subsidiaries (collectively, the "Claims"). If adversely determined, the
Claims will not, individually or in the aggregate, have a Material Adverse
Effect on Riverbed. There is no judgment, decree, order, injunction,
stipulation, award or writ of any Governmental Authority outstanding against
Riverbed or any of its Subsidiaries.

       Section 4.9 Employee Benefit Plans and Related Matters; ERISA.

       (a)    Schedule 4.9 to the Disclosure Letter contains a complete and
accurate list of all Riverbed Plans and Riverbed Benefit Arrangements and
specifically identifies all Riverbed Plans (if any) that are Qualified Plans.

       (b)    With respect, as applicable, to Benefit Plans and Benefit
Arrangements:

              (i)    Riverbed has delivered or made available true, correct, and
                     complete copies of the following documents with respect to
                     all Riverbed Plans and Riverbed Benefit Arrangements to
                     Aether: (A) all plan or arrangement documents, including
                     but not limited to trust agreements, insurance policies,
                     service agreements and formal and informal amendments to
                     each; (B) the most recent Forms 5500 or 5500C/R and any
                     attached financial statements and related actuarial
                     reports, and those for the prior three years; (C) the last
                     IRS determination letter, the last IRS determination letter
                     that

                                                                              20
<PAGE>   26

                     covered the qualification of the entire plan (if
                     different), and the materials submitted to obtain those
                     letters; (D) summary plan descriptions and summaries of
                     material modifications, and any prospectuses that describe
                     the Riverbed Benefit Arrangements or Riverbed Plans; (E)
                     written descriptions of all non-written agreements relating
                     to any such plan or arrangement; (F) all reports submitted
                     within the three years preceding the date of this Agreement
                     by third-party administrators, actuaries, investment
                     managers, consultants, or other independent contractors
                     (other than participant statements); (G) all notices that
                     the IRS, Department of Labor or any other governmental
                     agency or entity issued to the Seller within the four years
                     preceding the date of this Agreement; (H) employee manuals
                     or handbooks containing personnel or employee relations
                     policies; (I) the most recent quarterly listing of workers'
                     compensation claims and a schedule of workers' compensation
                     claims of the Seller for the last three fiscal years; and
                     (J) any other documents Aether has requested;

              (ii)   the Qualified Plans qualify under Section 401(a) of the
                     Code, and nothing has occurred with respect to the
                     operation of any Qualified Plan that could cause the
                     imposition of any liability, lien, penalty, or tax under
                     ERISA or the Code; each Riverbed Plan and each Riverbed
                     Benefit Arrangement has been maintained in all material
                     respects in accordance with its constituent documents and
                     with all applicable provisions of domestic and foreign
                     laws, including federal and state securities laws and any
                     reporting and disclosure requirements; with respect to each
                     Riverbed Plan, no transactions prohibited by Code Section
                     4975 or ERISA Section 406 and no breaches of fiduciary duty
                     described in ERISA Section 404 have occurred, and no
                     Riverbed Plan contains any security issued by any Related
                     Employer;

              (iii)  the Related Employers have never sponsored or maintained,
                     had any obligation to sponsor or maintain, or had any
                     liability (whether actual or contingent, with respect to
                     any of their assets or otherwise) with respect to any
                     Benefit Plan subject to Section 302 of ERISA or Section 412
                     of the Code or Title IV of ERISA (including any
                     Multiemployer Plan);

              (iv)   there are no pending claims (other than routine benefit
                     claims) or lawsuits that have been asserted or instituted
                     by, against, or relating to, any Riverbed Plans or Riverbed
                     Benefit Arrangements, nor is there any basis for any such
                     claim or lawsuit. No Riverbed Plans or Riverbed Benefit
                     Arrangements are or have been under audit or examination
                     (nor has notice been received of a potential audit or
                     examination) by any domestic or foreign governmental agency
                     or entity, and no matters are pending with respect to any
                     Riverbed Plan under the IRS's Employee Plans Compliance
                     Resolutions System or any successor or predecessor program;

              (v)    no Riverbed Plan or Riverbed Benefit Arrangement contains
                     any provision or is subject to any law that would
                     accelerate or vest any benefit or require severance,
                     termination or other payments or trigger any liabilities as
                     a result of the transactions this Agreement contemplates;
                     no Related



                                                                              21
<PAGE>   27

                     Employer has declared or paid any bonus or incentive
                     compensation related to the transactions this Agreement
                     contemplates; and no payments under any Riverbed Plan or
                     Riverbed Benefit Arrangement would, individually or
                     collectively, be nondeductible under Code Section 280G;

              (vi)   all reporting, disclosure, and notice requirements of ERISA
                     and the Code have been satisfied in all material respects
                     with respect to each Riverbed Plan and each Riverbed
                     Benefit Arrangement;

              (vii)  each Related Employer has paid all amounts it is required
                     to pay as contributions to the Riverbed Plans as of the
                     date of this Agreement; all benefits accrued under any
                     unfunded Riverbed Plan or Riverbed Benefit Arrangement will
                     have been paid, accrued, or otherwise adequately reserved
                     in accordance with GAAP as of the date of this Agreement;
                     and all monies withheld from employee paychecks with
                     respect to Riverbed Plans have been transferred to the
                     appropriate plan within 30 days of such withholding;

              (viii) to Riverbed's Knowledge, no statement, either written or
                     oral, has been made by the Related Employers to any person
                     with regard to any Riverbed Plan or Riverbed Benefit
                     Arrangement that was not in accordance with the Riverbed
                     Plan or Riverbed Benefit Arrangement and that would involve
                     a material increase in expense or liability under such plan
                     or arrangement;

              (ix)   the Related Employers have no liability (whether actual,
                     contingent, with respect to any of its assets or otherwise)
                     with respect to any Benefit Plan or Benefit Arrangement
                     that is not a Riverbed Plan or Riverbed Benefit Arrangement
                     or with respect to any Benefit Plan sponsored or maintained
                     (or which has been or should have been sponsored or
                     maintained) by any ERISA Affiliate; and

              (x)    all group health plans of the Related Employers materially
                     comply with the requirements of Part 6 of Title I of ERISA
                     ("COBRA"), Code Section 5000, and the Health Insurance
                     Portability and Accountability Act; the Related Employers
                     have no liability under or with respect to COBRA for their
                     own actions or omissions or those of any predecessor; the
                     Related Employers' voluntary employee beneficiary
                     association, if any, is exempt from tax and complies with
                     all requirements applicable to it; no employee or former
                     employee (or beneficiary of either) of a Related Employer
                     is entitled to receive any benefits, including, without
                     limitation, death or medical benefits (whether or not
                     insured) beyond retirement or other termination of
                     employment, other than as applicable laws require.

       Section 4.10 Labor and Employment Matters. With respect to employees of
and service providers to the Related Employers:

       (a)    the Related Employers are complying and have complied in all
material respects with all applicable domestic and foreign laws respecting
employment and employment practices, terms and conditions of employment and
wages and hours, including without limitation any such laws respecting
employment discrimination, workers' compensation, family and medical leave,



                                                                              22
<PAGE>   28

the Immigration Reform and Control Act, and occupational safety and health
requirements, and no claims or investigations are pending or, to the Knowledge
of Riverbed, threatened with respect to such laws, either by private individuals
or by governmental agencies;

       (b)    no Related Employer is or has been engaged in any unfair labor
practice, and there is not now, nor within the past three years has there been,
any unfair labor practice complaint against any Related Employer pending or, to
the Knowledge of Riverbed, threatened, before the National Labor Relations Board
or any other comparable foreign or domestic authority or any workers' council;

       (c)    no labor union represents or has ever represented the Related
Employers' employees and no collective bargaining agreement is or has been
binding against any Related Employer. No Related Employer is currently
negotiating to create such agreements. No grievance or arbitration proceeding
arising out of or under collective bargaining agreements or employment
relationships is pending, and no claims therefor exist or have, to the Knowledge
of Riverbed, been threatened;

       (d)    no labor strike, lock-out, slowdown, or work stoppage is or has
ever been pending or threatened against or directly affecting any Related
Employer; and

       (e)    all persons who are or were performing services for any Related
Employer and are or were classified as independent contractors do or did satisfy
and have satisfied the requirements of law to be so classified, and the
appropriate Related Employer has fully and accurately reported their
compensation on IRS Forms 1099 when required to do so.

       Section 4.11 Insurance. Schedule 4.11 to the Disclosure Letter sets forth
(a) an accurate list of each material insurance policy providing coverage for
liability exposure (including policies providing property, casualty, liability
and workers' compensation coverage and bond and surety arrangements) to which
each of Riverbed and its Subsidiaries is currently, or has been during the past
three years, a party, a named insured or otherwise the beneficiary of coverage
and (b) all insurance loss runs or workers' compensation claims received for the
past three policy years. With respect to each such insurance policy, to the
Knowledge of each of Riverbed and its Subsidiaries: (a) the policy is legal,
valid, binding, enforceable and in full force and effect; (b) there will be no
breach or other violation of the policy resulting from the Transactions; and (c)
each of Riverbed and its Subsidiaries is not in breach or default (including
with respect to the payment of premiums or the giving of notices); and (d) no
event has occurred which, with notice or the lapse of time, would constitute
such a breach or default, or permit termination, modification or acceleration,
under the policy.



                                                                              23
<PAGE>   29

       Section 4.12 Brokers. Other than Morgan Stanley Dean Witter (the
"Riverbed Financial Advisor"), no broker, finder or investment banker is
entitled to any brokerage, finder's or other fee or commission in connection
with the Transactions based on any arrangement or agreement made by or on behalf
of each of Riverbed and its Subsidiaries.

       Section 4.13 Taxes.

       (a)    Except as set forth in Schedule 4.13(a) of the Disclosure Letter,
each of Riverbed and its Subsidiaries has timely filed all Tax Returns that were
required to be filed as of the Effective Time, and all such Tax Returns are
true, correct and complete in all material respects.

       (b)    Each of Riverbed and its Subsidiaries has paid in full on a timely
basis all Taxes owed by it, whether or not shown on any Tax Return.

       (c)    The liability of each of Riverbed and its Subsidiaries for unpaid
Taxes did not, as of the dates of the financial statements described in Section
4.6, exceed the current liability accruals for Taxes (excluding reserves for
deferred Taxes) set forth on such financial statements. The liability of each of
Riverbed and its Subsidiaries for unpaid Taxes as of the Effective Day will not
exceed such accruals as adjusted on the books of Riverbed in accordance with
past practices to reflect transactions occurring in the ordinary course of
business though the Effective Day.

       (d)    There are no ongoing audits, examinations or claims procedures
against Riverbed or any of its Subsidiaries for Taxes, and no written notice of
any audit, examination, or claim for Taxes, whether pending or threatened, has
been received.

       (e)    Riverbed has a taxable year ending on December 31, in each year
commencing 1998.

       (f)    Each of Riverbed and its Subsidiaries currently utilizes the
accrual method of accounting for income tax purposes and such method of
accounting has not changed since its incorporation. Neither Riverbed nor any of
its Subsidiaries has agreed to, and is not and will not be required to, make any
adjustments under Code section 481(a) as a result of a change in accounting
methods.

       (g)    Each of Riverbed and its Subsidiaries has withheld and paid over
to the proper governmental authorities all Taxes required to have been withheld
and paid over, and complied with all information reporting and backup
withholding requirements, including maintenance of required records with respect
thereto, in connection with amounts paid to any employee, independent
contractor, creditor, or other third party.

       (h)    Neither Riverbed nor any of its Subsidiaries has entered into any
agreement extending, or having the effect of extending, the period of assessment
or collection of any Taxes and no power of attorney with respect to any Taxes
has been executed or filed with the IRS or any other taxing authority.

       (i)    Copies of filed Tax Returns of each of Riverbed and its
Subsidiaries for taxable years beginning after December 31, 1997, and copies of
any Tax examinations, audit reports, or



                                                                              24
<PAGE>   30

notices of deficiencies of each of Riverbed and its Subsidiaries, without regard
to time, have been delivered to Aether.

       (j)    There are (and as of immediately following the Closing there will
be) no Liens on the assets of Riverbed or any of its Subsidiaries relating to or
attributable to Taxes (other than Permitted Liens).

       (k)    There is no reasonable basis for the assertion of any claim
relating or attributable to Taxes which, if adversely determined, would result
in any Lien (other than Permitted Liens) on the assets of Riverbed or any of it
Subsidiaries.

       (l) Neither Riverbed nor any of its Subsidiaries has filed any
consent agreement under Section 341(f) of the Code or agreed to have Section
341(f)(2) of the Code apply to any disposition of a subsection (f) asset (as
defined in Section 341(f)(4) of the Code).

       (m)    Neither Riverbed nor any of its Subsidiaries is, or has ever been,
a party to a Tax sharing, Tax indemnity or Tax allocation agreement, and neither
Riverbed nor any of its Subsidiaries has assumed the Tax liability of any other
Person under contract.

       (n)    Neither Riverbed nor any of its Subsidiaries is, or has ever been,
a "United States real property holding corporation" within the meaning of
Section 897(c)(2) of the Code.

       (o)    Neither Riverbed nor any of its Subsidiaries has been a member of
an affiliated group filing a consolidated federal income Tax Return other than a
group of which Riverbed is the common parent. Neither Riverbed nor any of its
Subsidiaries has any liability for the Taxes of another Person under Treas. Reg.
Section 1.1502-6 (or any similar provision of state, local or foreign law) as a
transferee or successor, by contract or otherwise.

       (p)    Neither Riverbed nor any of its Subsidiaries is a party to any
joint venture, partnership or other arrangement that is treated as a partnership
for federal income tax purposes. (q) Schedule 4.13

       (q)    contains accurate and complete descriptions of Riverbed and each
of its Subsidiaries' basis in its assets.



                                       25
<PAGE>   31

       Section 4.14 Environmental Matters. Each of Riverbed and its Subsidiaries
is in compliance in all material respects with all environmental laws, rules,
regulations and standards promulgated, adopted or enforced by the Environmental
Protection Agency ("EPA") and of similar agencies in states in which they
conduct their respective businesses. There is no suit, claim, action or
proceeding now pending before any court, governmental agency or board or other
forum or, to the Knowledge of each of Riverbed and its Subsidiaries, threatened
by any Person, (a) for alleged noncompliance with any environmental law, rule or
regulation or (b) relating to the discharge or release into the environment of
any hazardous material or waste at or on a site presently or formerly owned,
leased or operated by each of Riverbed and its Subsidiaries.

       Section 4.15 Intellectual Property.

       (a)    Schedule 4.15(a) to the Disclosure Letter lists: (i) all
applications and registrations for patents, copyrights, trademarks, service
marks and trade dress which are included in the Riverbed Intellectual Property
and are owned by or on behalf of each of Riverbed and its Subsidiaries; (ii) all
material hardware products and tools, software products and tools, and services
that are currently published, offered, or under development, including a list of
marketing, research, development or any other current or future official
business related projects currently under consideration, by each of Riverbed and
its Subsidiaries; (iii) all material licenses, sublicenses and other agreements
to which each of Riverbed and its Subsidiaries is a party and pursuant to which
each of Riverbed and its Subsidiaries authorizes any other person to use the
Riverbed Intellectual Property or exercise any other right with regard thereto
and (iv) all material Third Party Intellectual Property.

       (b)    In addition to Intellectual Property defined in Section 1.1,
Riverbed Intellectual Property also consists of (i) items and rights solely
owned by Riverbed, (ii) the subject matter disclosed in U.S. Patent Application
Serial No. 09/235,808 (the '808 Patent Application), filed January 22, 1999,
entitled "SYSTEM, METHOD AND MEANS FOR CONVEYING INFORMATION BETWEEN A REMOTE
DEVICE AND A CENTRAL COMPUTER," and (iii) any and all inventions conceived or
reduced to practice on or before the Closing Date by Riverbed employees,
Officers or any party that has an obligation to assign such inventions to
Riverbed.

       (c)    Each of Riverbed and its Subsidiaries has all rights, title and
interest in the Riverbed Intellectual Property, and all necessary licenses,
permissions and other rights in the Third Party Intellectual Property, necessary
to carry out the business of Riverbed or its Subsidiaries as it has been, is
currently, or is reasonably anticipated (as of the date of this Agreement and as
of the Closing) by Riverbed and its Subsidiaries to be, conducted.

       (d)    Each of Riverbed and its Subsidiaries is the rightful owner of any
and all rights in Riverbed Intellectual Property for its current technologies or
those under development by Riverbed or its subsidiaries on or before the Closing
Date, including without limitation rights to make, use, import, reproduce,
modify, adapt, create derivative works based on, translate, distribute (directly
and indirectly), transmit, display and perform publicly, license, rent, lease,
assign, and sell the Riverbed Intellectual Property and products embodying the
Riverbed Intellectual Property, in all fields of use, in each country in which
Riverbed conducts business,



                                                                              26
<PAGE>   32

and to sublicense any or all such rights to third parties, including the right
to grant further sublicenses.

       (e)    Each of Riverbed and its Subsidiaries has obtained the rights to
Riverbed Intellectual Property in writing from its officers, employees and third
parties, including independent contractors, sub-contractors, and NobleStar, to
assign, license, sublicense, transfer or grant any and all the rights and
licenses conveyed under this Agreement.

       (f)    All necessary registration, maintenance and renewal fees currently
due have been made with respect to, and all necessary documentation,
recordations and certifications have been filed with the relevant authorities
for purposes of maintaining, all Riverbed Intellectual Property applications and
registrations listed on Schedule 4.15(a) to the Disclosure Letter.

       (g)    Each of Riverbed and its Subsidiaries' employees and officers has
taken any and all reasonably necessary steps to protect material Riverbed
Intellectual Property, including securing patent, copyright, trademark, trade
secret, mask works or other intellectual property rights, as appropriate, in
works of authorship, inventions, trade secrets and other confidential
information conceived or reduced to practice on or before the Closing Date.
Except with respect to the '808 application, each of Riverbed and its
Subsidiaries' employees and officers has exercised reasonable efforts and due
diligence to protect Riverbed Intellectual property and has not engaged or will
not engage in an act or omission that would prevent, now, or in the future,
securing or protecting Riverbed Intellectual Property and rights in current
technologies or those under development. Each of Riverbed and its Subsidiaries,
employees, or officers has not engaged in any act or omission that would
constitute a bar to the U.S. patentability of any patent applications listed on
Schedule 4.15(a), or any patent applications being prepared for filing,
including but not limited to, any publication, public use, or offer for sale of
an invention.

       (h)    Each of Riverbed and its Subsidiaries, employees, or officers has
complied with the required duty of candor before the United States Patent and
Trademark Office in connection with any patent application filed on behalf of
Riverbed or in connection with any Riverbed Intellectual Property.

       (i)    Each of Riverbed and its Subsidiaries' current use, reproduction,
modification, distribution, licensing, sublicensing, sale, or any other exercise
of, or use, reproduction, modification, distribution, licensing, sublicensing,
sale, or any other exercise of any Riverbed Intellectual Property currently
reasonably anticipated by Riverbed (including rights in any product, work,
technology, service or process) does not, to Riverbed's Knowledge, interfere
with, infringe upon, or misappropriate any copyright, patent, trade secret,
trademark, service mark, trade name, firm name, logo, trade dress, mask work,
moral right, other Intellectual Property right, right of privacy or right in
personal data of any person.

       (j)    Each of Riverbed and its Subsidiaries' commercially available
products, including hardware or software products and tools, services, or
technologies, either alone or in combination, do not, to Riverbed's Knowledge,
infringe any patent or other intellectual property right or similar right of a
third party.

                                                                              27
<PAGE>   33

       (k)    The current versions of each of Riverbed and its Subsidiaries'
products substantially conform to the current published specifications and
marketing materials relating to such products.

       (l)    Each of Riverbed and its Subsidiaries has obtained written
agreements from all of its officers, employees and third party contractors or
agents (other than its law firms, accounting firms and other professional
advisors that are subject to preexisting confidentiality obligations to
Riverbed) to not assert any intellectual property right, including any patent,
copyright, trademark, trade secret, rights in mask works or other intellectual
property rights, included in or relating to the Riverbed Intellectual Property.

       (m)    Each of Riverbed and its Subsidiaries is not, nor as a result of
the execution or delivery of this Agreement, or performance of Riverbed's
obligations hereunder, will each of Riverbed and its Subsidiaries be, in
violation or default of any license, sublicense or other agreement to which each
of Riverbed and its Subsidiaries is a party or otherwise bound. The consummation
of the transactions contemplated by this Agreement will not trigger the release
of any of each of Riverbed and its Subsidiaries' source code to any third party.
Each of Riverbed and its Subsidiaries is not in breach or default in any respect
under any agreement or arrangement relating to Third Party Intellectual
Property, nor has each of Riverbed and its Subsidiaries given or received a
notice of default under any agreement or arrangement relating to Third Party
Intellectual Property incorporated in each of Riverbed and its Subsidiaries'
products, including hardware or software products and tools, services, or
technologies. Each item of Intellectual Property owned or used by each of
Riverbed and its Subsidiaries immediately prior to the Closing hereunder will
continue to be owned or available for use by the Surviving Corporation on
identical terms and conditions immediately subsequent to the Closing hereunder.


       (n)    Except as set forth in Schedule 4.15(n) of the Disclosure Letter,
each of Riverbed and its Subsidiaries is not obligated to provide any
consideration (whether financial or otherwise) to any third party, nor is any
third party otherwise entitled to any consideration, with respect to any
exercise of rights by Riverbed in the Riverbed Intellectual Property or the
Third Party Intellectual Property.

       (o)    Except as set forth in Schedule 4.15(o) of the Disclosure Letter,
no claim, complaint, demand or notice (i) challenging the validity,
effectiveness, or ownership by Riverbed of any of the Riverbed Intellectual
Property, (ii) charging that either Riverbed or any Subsidiary has not performed
its obligations under any license, sublicense, or agreement relating to the
Third Party Intellectual Property, (iii) to the effect that the use,
reproduction, modification, distribution, licensing, sublicensing, sale, or any
other exercise of, or Riverbed's reasonably anticipated use, reproduction,
modification, distribution, licensing, sublicensing, sale, or any other exercise
of any Riverbed Intellectual Property (including rights in any product, work,
technology, service or process as used, provided or offered at any time)
interferes with, infringes upon, or misappropriates or will interfere with,
infringe upon, or misappropriate any Intellectual Property or other proprietary
or personal right of any person, has ever been, to the Knowledge of Riverbed,
alleged, asserted or threatened by any person, nor, to the Knowledge of
Riverbed, are there nor has there ever been any valid grounds for any bona fide
claim, complaint, demand or notice of any such kind.



                                                                              28
<PAGE>   34

       (p)    To the Knowledge of Riverbed, there is no unauthorized use,
infringement or misappropriation of any of the Riverbed Intellectual Property by
any third party, employee or former employee.

       (q)    No parties other than Riverbed possess any current or contingent
rights to any source code which is part of the Riverbed Intellectual Property.


       (r)    Schedule 4.15(r) to the Disclosure Letter lists all Persons who
have created any portion of, or otherwise have any rights as authors or
inventors in or to, the Riverbed Intellectual Property. Riverbed has secured
from all such Persons, including all Persons currently or formerly employed or
engaged as an employee or consultant, valid and enforceable written assignments
of any such work or other rights, confidentiality agreements, and non-disclosure
agreements for the purpose of protecting the confidential information of
Riverbed and has provided true and complete copies of such assignments and
agreements to the Surviving Company.

       (s)    Schedule 4.15(s) to the Disclosure Letter includes a true and
complete list of support and maintenance agreements relating to Riverbed
Intellectual Property.

       (t)    Each of Riverbed and its Subsidiaries has not granted any
exclusive licenses in the Riverbed Intellectual Property to third parties, and
no Person has a license to use or the right to acquire a license to use any
future version of Riverbed's software programs or any future product based on
the Riverbed Intellectual Property other than a right to license such updates
to, new releases of and new versions of Riverbed's software programs that
Riverbed makes generally available to its licensees.

       Section 4.16 Books and Records. The books and records, minutes books,
stock record books and other records of each of Riverbed and its Subsidiaries
and all of its Subsidiaries, all of which have been made available to Aether,
are complete and correct in all material respects and have been maintained in
accordance with sound business practices, except for minutes of meetings of the
Board of Directors that have not been completed or approved by the Board of
Directors as of the date of this Agreement (provided that summaries of any such
minutes have been made available to Aether). The respective minutes books of
each of Riverbed and its Subsidiaries and each of its Subsidiaries contain
accurate and complete records of all meetings held of, and corporate action
taken by, the stockholders and the Boards of Directors of each of Riverbed and
its Subsidiaries. Riverbed has not engaged in any transactions that individually
or in the aggregate are material to Riverbed and its Subsidiaries that have not
been reflected in its books and records.

       Section 4.17 Transactions with Affiliates. Except as set forth on
Schedule 4.17 to the Disclosure Letter, since October 21, 1998, each of Riverbed
and its Subsidiaries has not entered into any transaction with any current
director, officer or 5% or larger shareholder of each of Riverbed and its
Subsidiaries, and all ongoing contracts with any director or officer are on
arms' length terms no less favorable to each of Riverbed and its Subsidiaries
than would have been obtained from any unaffiliated third party.



                                                                              29
<PAGE>   35

       Section 4.18 Opinion of Financial Advisor. The Riverbed Financial Advisor
has delivered to Riverbed an opinion dated the date of this Agreement to the
effect that the Merger Consideration to be received by the holders of the issued
and outstanding shares of the Riverbed Capital Stock is fair from a financial
point of view to the holders of the Riverbed Capital Stock.

       Section 4.19 Reliance. In entering into this Agreement, Riverbed has
relied solely on representations made in this Agreement, including the Aether
SEC Reports, and any certificates and documents required to be provided by
Aether and Merger Sub pursuant to this Agreement. Riverbed has been represented
by counsel and has had sufficient opportunity to examine and understand the
business and assets of Aether.

       Section 4.20 Disclosure. All written agreements, lists, schedules,
instruments, exhibits, documents, certificates, reports, statements and other
writings furnished to Aether and any of its Representatives pursuant hereto or
in connection with this Agreement or the transactions contemplated hereby, are
and will be complete and true copies of such materials. No representation or
warranty by Riverbed contained in this Agreement, in the Schedules attached to
the Disclosure Letter or in any certificate furnished or to be furnished in
connection herewith or pursuant hereto contains or will contain any untrue
statement of a material fact or omits or will omit to state any material fact
necessary in order to make any statement contained herein or therein not
misleading.

       Section 4.21 Material Contracts. Schedule 4.21 to the Disclosure Letter
is a complete and accurate list of all agreements to which Riverbed or any of
its Subsidiaries is a party that obligates Riverbed or any Subsidiary to pay, or
entitles them to receive, amounts of $10,000 or greater ("Material Contracts").
All Material Contracts (including the Palm Computing Contracts) are in full
force and effect and are not subject to any default thereunder by any party.
Riverbed has obtained, or will obtain prior to the Effective Time, all necessary
consents, waivers and approvals of parties to the Material Contracts that are
required in connection with any of the transactions contemplated hereby, or as
are required by any governmental agency or other third party or are advisable in
order that any such Material Contract remain in effect without modification
after the Merger and without giving rise to any right to termination,
cancellation or acceleration or loss of any right or benefit ("Riverbed Third
Party Consents"). All Riverbed Third Party Consents are listed in Schedule 4.5
to the Disclosure Letter.

       Section 4.22 Year 2000.

       (a)    All computer hardware products and tools and software products and
tools currently marketed and licensed by Riverbed to others are Year 2000
Compliant.

       (b)    Riverbed has either obtained written representations or assurances
from or has reviewed the relevant corporate web sites regarding Year 2000
Compliance of, each third party that provides material products or services to
Riverbed and (A) provides date information or any data that are derived from or
dependent on date information or Date-Sensitive Systems, (B) processes date
information or any data that are derived from or dependent on date information,
or (C) otherwise provides any material product or service, and Riverbed has
satisfied itself, in the exercise of reasonable care, that such third party's
date information, data derived or dependent on date information and
Date-Sensitive Systems are either Year 2000 Compliant or that the



                                       30
<PAGE>   36

failure of such information, data or systems to be Year 2000 Compliant will not
have a material adverse effect on the business or prospects of Riverbed.

       Section 4.23 Distribution. Since December 31, 1998, Riverbed has not
declared, set aside, made or paid any dividend or other distribution, payable in
cash, stock, property or otherwise, with respect to any of its Capital Stock, or
subdivided, reclassified, recapitalized, split, combined or exchanged any of its
capital stock or other equity securities.

       Section 4.24 Real Property. Riverbed does not own and never has owned any
Real Property in fee. "Real Property" means all interests in real property,
including, without limitation, improvements, and fixtures located on such real
property. All oral or written lease, subleases, licenses, concession agreements
or other use or occupancy agreements pursuant to which Riverbed leases to or
from any other party any real property, including all renewals, extensions,
modifications or supplements to any of the foregoing or substitutions for any of
the foregoing (collectively, the "Leases"), are valid and in full force and
effect, and have not been assigned, modified, supplemented or amended. Riverbed
leases all Real Property necessary to conduct its business. Riverbed has made
available to Aether true and complete copies of all of the Leases, all
amendments thereto, and all material correspondence related thereto, including
all correspondence pursuant to which any party to any of the Leases declared a
default thereunder or provided notice of the exercise of any operation granted
to such party under such Lease. The Leases and Riverbed's interests thereunder
are free of all Liens, other than Permitted Liens.

       Section 4.25 Personal Property. Schedule 4.25 to the Disclosure Letter
sets forth an accurate list of all personal property owned or leased by Riverbed
with a current book value in excess of $25,000. Riverbed currently owns or
leases all personal property necessary to conduct the business and operations of
Riverbed.




                                                                              31
<PAGE>   37






                                   ARTICLE V.

             REPRESENTATIONS AND WARRANTIES OF AETHER AND MERGER SUB

            Aether and Merger Sub hereby represent and warrant to Riverbed that:

       Section 5.1 Organization and Qualifications; Subsidiaries. Aether, Merger
Sub and each Material Subsidiary of Aether is a corporation, partnership,
limited liability company or other legal entity duly organized, validly existing
and in good standing under the laws of the jurisdiction of its incorporation or
organization and has the corporate power and authority and all necessary
governmental approvals to own, lease and operate its properties and to carry on
its business as it is now being conducted, except where failure to obtain such
approvals would not have a Material Adverse Effect upon Aether. Each of Aether,
Merger Sub and each Material Subsidiary of Aether is duly qualified or licensed
as a foreign corporation, partnership or limited liability company to transact
business, and is in good standing, in each jurisdiction where the character of
the properties owned, leased or operated by it or the nature of its business
makes such qualification or licensing necessary and where the failure to so
qualify would cause a Material Adverse Effect upon such entity. Merger Sub is a
direct wholly-owned Subsidiary of Aether.

       Section 5.2 Charter and Bylaws. Complete and correct copies of the
charter and bylaws of Aether and Merger Sub, as amended to date, have been made
available to Riverbed. Such Organizational Documents are in full force and
effect and have not been amended or modified in any respect. Aether is not in
violation of any provision of its Organizational Documents. No Subsidiary of
Aether is in violation of any provision of its Organizational Documents.

       Section 5.3 Capitalization. The authorized capital stock of Aether
consists of 75,000,000 shares of Aether Common Stock, par value $.01 per share,
and 1,000,000 shares of preferred stock of Aether, par value $.01 per share. As
of December 31, 1999, (i) (A) 27,154,398 shares of Aether Common Stock were
issued and outstanding, all of which were validly issued, fully paid and
nonassessable, and (B) zero (0) shares of preferred stock of Aether were issued
and outstanding; and (ii)(A) 5,400,000 shares of Aether Common Stock were
reserved for issuance under Aether employee or director benefit programs
(collectively, the "Aether Stock Plans"), (B) zero (0) shares of Aether Common
Stock were classified as treasury shares, and (C) Options to purchase 4,820,217
shares of Aether Common Stock were issued and outstanding, all of which were
validly issued, fully paid and nonassessable. Except as set forth above, no
shares of Aether Common Stock or other voting securities of Aether are issued,
reserved for issuance or outstanding. All shares of Aether Common Stock subject
to issuance as aforesaid and all shares of Aether Common Stock subject to
issuance as Merger Consideration, upon issuance on the terms and conditions
specified in the instruments pursuant to which they are issuable, will be duly
authorized, validly issued, fully paid and nonassessable. There are no
outstanding contractual obligations of Aether to repurchase, redeem or otherwise
acquire any shares of Aether Common Stock or any other shares of capital stock
of Aether, or make any material investment (in the form of a loan, capital
contribution or otherwise) in any Subsidiary of



                                                                              32
<PAGE>   38

Aether or any other Person, other than a wholly-owned Subsidiary of Aether or a
Person wholly-owned by one or more wholly-owned Subsidiaries of Aether. Each
outstanding share of capital stock of each Subsidiary of Aether is duly
authorized, validly issued, fully paid and nonassessable and each such share
owned by Aether or any Subsidiary of Aether is owned free and clear of any Liens
except that the shares of OmniSky Corporation that are owned by a Subsidiary of
Aether are subject to certain Liens. All of the shares of Aether Common Stock to
be issued pursuant to the terms of this Agreement have been duly authorized and,
upon consummation of the Merger, shall be validly issued, fully paid and
nonassessable.

       Section 5.4 Authority Relative to This Agreement. Aether and Merger Sub
have all necessary corporate power and authority to execute and deliver this
Agreement, and to perform its obligations hereunder and to consummate the
Transactions. The execution and delivery of this Agreement by Aether and Merger
Sub, the performance by Aether and Merger Sub of its obligations hereunder and
the consummation by Aether and Merger Sub of the Transactions have been duly and
validly approved by the Board of Directors of Aether and Merger Sub, and no
other corporate proceedings on the part of Aether and Merger Sub are necessary
to authorize this Agreement or to consummate the Transactions (other than the
Merger Filing) . This Agreement has been duly and validly executed and delivered
by Aether and Merger Sub and, assuming the due authorization, execution and
delivery thereof by Riverbed, constitutes the legal, valid and binding
obligation of Aether and Merger Sub, enforceable against Aether and Merger Sub
in accordance with its terms, except as enforceability may be limited by
bankruptcy and other similar laws and general principles of equity.

       Section 5.5 No Conflict; Required Filings and Consents. The execution and
delivery of this Agreement by Aether and Merger Sub do not, and the performance
of their respective obligations under this Agreement and the consummation of the
Transactions by Aether and Merger Sub will not, (a) conflict with, result in a
breach of, cause a dissolution or require the consent or approval of any Person
under, or violate any provision of, the Organizational Documents of Aether or
Merger Sub, (b) require any consent, approval, authorization or permit of, or
filing with or notification to, any Governmental Authority, except for (i)
applicable requirements, if any, of the Exchange Act, the Securities Act, the
Blue Sky Laws and the HSR Act, in each case, including any rules and regulations
promulgated thereunder, (ii) the Merger Filing, (iii) the Riverbed Stockholder
Approval, and (iv) such other consents, authorizations, filings, approvals and
registrations which if not obtained or made would not have a Material Adverse
Effect, (c) subject to the making of the filings and obtaining the approvals
identified in clause (b), conflict with or violate any Law, judgment, order,
writ, injunction or decree applicable to Aether or Merger Sub or by which any
property or asset of Aether or Merger Sub is bound or affected, which conflict
or violation would result in a loss of material benefits to or in any material
liability to Riverbed, Aether or the Surviving Corporation, or (d) conflict with
or result in any breach of or constitute a default (or an event which with
notice or lapse of time or both would become a default) under, result in the
loss by Aether or Merger Sub or modification in a manner materially adverse to
Aether or Merger Sub of any right or benefit under, or give to others any right
of termination, amendment, acceleration, repurchase or repayment, increased
payments or cancellation of, or result in the creation of a Lien or other
encumbrance on any Aether Common Stock issued pursuant to the Merger or any
material property or asset of Aether or Merger Sub or any Subsidiary of Aether
or Merger Sub pursuant to, any Contract of Aether or



                                                                              33
<PAGE>   39

Merger Sub, except, in each case, such as would not, individually or in the
aggregate have a Material Adverse Effect on Aether.

       Section 5.6 SEC Reports and Financial Statements. Each form, report,
schedule, registration statement and definitive proxy statement filed by Aether
with the SEC prior to the date hereof (as such documents have been amended prior
to the date hereof, the "Aether SEC Reports"), as of their respective dates,
complied in all material respects with the applicable requirements of the
Securities Act and the Exchange Act and the rules and regulations thereunder.
None of the Aether SEC Reports, as of the date on which such SEC Report was
declared effective pursuant to the Securities Act or the date on which such SEC
Report was filed pursuant to the Exchange Act, as applicable, contained or
contains any untrue statement of a material fact or omits to state a material
fact required to be stated therein or necessary to make the statements therein,
in light of the circumstances under which they were made, not misleading. The
consolidated financial statements of Aether and its Subsidiaries included in
such reports comply as to form in all material respects with applicable
accounting requirements and with the published rules and regulations of the SEC
with respect thereto, have been prepared in accordance with GAAP, consistently
applied (except, in the case of the unaudited interim financial statements, as
permitted by Form 10-Q of the SEC) and fairly present in all material respects
(subject, in the case of the unaudited interim financial statements, to normal,
year-end audit adjustments) the consolidated financial position of Aether and
its Subsidiaries as at the dates thereof and the consolidated results of their
operations and cash flows for the periods then ended. Except as set forth in
Schedule 5.6 to the Aether Disclosure Letter, since September 30, 1999, neither
Aether nor any of its Subsidiaries has incurred any liabilities or obligations
(whether absolute, accrued, fixed, contingent, liquidated, unliquidated or
otherwise and whether due or to become due) of any nature, except liabilities,
obligations or contingencies (a) which are reflected on the consolidated balance
sheet of Aether and its Subsidiaries as at September 30, 1999 (including the
notes thereto) or (b) which (i) were incurred in the ordinary course of business
after September 30, 1999 and consistent with past practices, or (ii) are
disclosed in the Aether SEC Reports. Since October 20, 1999, Aether has timely
filed with the SEC all forms, reports and other documents required to be filed
prior to the date hereof, and no Subsidiary of Aether has filed, or been
required to file, any form, report or other document with the SEC, in each case,
pursuant to the Securities Act, the Exchange Act or the rules and regulations
thereunder. Since September 30, 1999, except as described in the Aether SEC
Reports, there has been no change in any of the significant accounting
(including tax accounting) policies, practices or procedures of Aether or any
Subsidiary of Aether, except changes resulting from changes in accounting
pronouncements of Financial Accounting Standards Boards or changes in applicable
laws or rules or regulations thereunder.

       Section 5.7 Brokers. Other than BancBoston Robertson Stephens, Inc., no
broker, finder or investment banker is entitled to any brokerage, finder's or
other fee or commission in connection with the Transactions based on any
arrangement or agreement made by or on behalf of Aether.

       Section 5.8 Conformity with Law; Relations with Governments; Litigation.
Aether and its Subsidiaries have not violated any law or regulation or any order
of any Governmental Authority having jurisdiction over it which would have a
Material Adverse Effect. Aether has not offered anything of value to any
governmental official, political party or candidate for



                                                                              34
<PAGE>   40

government office nor has it otherwise taken any action that would cause Aether
to be in violation of the Foreign Corrupt Practices Act of 1977, as amended.
Schedule 5.8 to the Aether Disclosure Letter lists, as of the date hereof, and
will list as of the Closing Date, all claims, suits, actions or proceedings
pending or, to the Knowledge of each of Aether and its Subsidiaries, threatened
or contemplated, including any investigations or reviews by any Governmental
Authority pending or, to the Knowledge of each of Aether and its Subsidiaries,
threatened or contemplated, against, relating to or affecting each of Aether and
its Subsidiaries. There is no judgment, decree, order, injunction, stipulation,
award or writ of any Governmental Authority outstanding against Aether or any of
its Subsidiaries.

       Section 5.9 Transactions with Affiliates. Except as set forth in Schedule
5.9 to the Aether Disclosure Letter, since October 20, 1999, each of Aether and
its Subsidiaries has not entered into any transaction with any current director,
officer or 5% or larger shareholder of each of Aether and its Subsidiaries.

       Section 5.10 Merger Sub. Except for obligations incurred in connection
with its incorporation or organization or the negotiation and consummation of
this Agreement and the transactions contemplated hereby, Merger Sub has neither
incurred any obligation or liability nor engaged in any business or activity of
any type or kind whatsoever or entered into any agreement or arrangement with
any person.

       Section 5.11 Reliance. In entering into this Agreement, Aether and Merger
Sub have relied solely on representations made in this Agreement and any
certificates and documents required to be provided by Riverbed pursuant to this
Agreement. Aether and Merger Sub have been represented by counsel and has had
sufficient opportunity to examine and understand the business and assets of
Riverbed.

       Section 5.12 Disclosure. All written agreements, lists, schedules,
instruments, exhibits, documents, certificates, reports, statements and other
writings furnished to Riverbed and any of its Representatives pursuant hereto or
in connection with this Agreement or the transactions contemplated hereby, are
and will be complete and true copies of such materials. No representation or
warranty by Aether contained in this Agreement, in the Schedules attached to the
Disclosure Letter or in any certificate furnished or to be furnished in
connection herewith or pursuant hereto contains or will contain any untrue
statement of a material fact or omits or will omit to state any material fact
necessary in order to make any statement contained herein or therein not
misleading, except for those facts already stated in an Aether SEC Report.

       Section 5.13 Absence of Changes. Except as set forth in Schedule 5.13 to
the Aether Disclosure Letter, since the date of the most recent Aether SEC
Report that has been filed with the SEC, there has not occurred or arisen any
event that, individually or in the aggregate, has had or, insofar as can be
reasonably foreseen, would have a Material Adverse Effect on Aether or any of
its Subsidiaries.

       Section 5.14 Information Supplied. None of the information supplied or to
be supplied by Aether for inclusion in the disclosure document relating to the
Riverbed Stockholder Meeting to be held in connection with the Merger (the
"Disclosure Document") will, at the date mailed to stockholders and at the time
of the Riverbed Stockholder Meeting, contain any untrue statement

                                                                              35

<PAGE>   41

of a material fact or omit to state any material fact required to be stated
therein or necessary in order to make the statements therein, in light of the
circumstances under which they are made, not misleading. If at any time prior to
the Effective Time any event in respect of Aether, its officers and directors or
any of its Subsidiaries should occur which is required to be described in an
amendment of, or a supplement to, the Disclosure Document, Aether shall promptly
so advise Riverbed and such event shall be so described, and such amendment or
supplement shall be promptly, to the extent required by Law, disseminated by
Riverbed to the stockholders of Riverbed.



                                                                              36

<PAGE>   42


                                   ARTICLE VI.

                                    COVENANTS

       Section 6.1 Notification of Certain Matters. Each of the parties hereto
shall give prompt notice to the other parties hereto of the occurrence or
nonoccurrence of any event to which such party becomes aware, the occurrence or
nonoccurrence of which would be reasonably likely to cause (a) any
representation or warranty contained in this Agreement to be untrue or
inaccurate in any material respect, or (b) any covenant, condition or agreement
contained in this Agreement not to be complied with or satisfied in any material
respect. The delivery of any notice pursuant to this Section 6.1 shall not limit
or otherwise affect the remedies available hereunder to the party receiving such
notice.

       Section 6.2 Further Action, Reasonable Efforts; Consents and Approvals.
Upon the terms and subject to the conditions hereof, each of the parties hereto
shall use commercially reasonable efforts to take, or cause to be taken, all
appropriate action, and to do, or cause to be done, all things necessary, proper
or advisable under applicable laws and regulations to consummate and make
effective the transactions in as expeditious a manner as is reasonably
practicable, including, without limitation, using commercially reasonable
efforts to obtain all licenses, permits, consents, approvals, authorizations,
certificates, qualifications and orders of, and make all filings and required
submissions with, all Governmental Authorities, and all shareholders, lenders
and partners of, and parties to Contracts with, Aether, Riverbed or any other
Person, in each case, as are reasonably necessary for the consummation of the
Transactions (collectively "Consents"), except for such consents, authorizations
filings, approvals and registrations which if not obtained or made would not
have a Material Adverse Effect on Riverbed or Aether. Riverbed shall, as soon as
possible prior to the Closing, deliver to Aether copies of all Consents obtained
by Riverbed. Aether shall, as soon as possible prior to the Closing, deliver to
Riverbed copies of all Consents obtained by Aether. In case at any time after
the Closing Date any further action is necessary or desirable to carry out the
purposes of this Agreement, each of Aether and Riverbed shall use its
commercially reasonable efforts to take all such action. Prior to the Closing,
each party shall use its commercially reasonable efforts not to take any action,
or enter into any transaction, that would cause any of its representations or
warranties contained in this Agreement to be untrue.

       Section 6.3 Regulatory Filings.

       (a)    On or before February 15, 2000, each of the parties will file and
Riverbed will cause any shareholder of Riverbed Capital Stock obligated to file
a Pre-Merger Notification and Report Forms if required under the HSR Act ("HSR
Filings").

       (b)    Without limiting the generality of Section 6.2 hereof, Aether and
Riverbed shall (i) take promptly all actions necessary to make the filings
required of Aether, Riverbed, or any of their respective Affiliates in order to
obtain any Requisite Regulatory Approval, (ii) comply at the earliest
practicable date with any request for information or documentary material
received by Aether, Riverbed, or any of their respective Affiliates from any
Governmental Authority and


                                                                              37

<PAGE>   43

(iii) cooperate with each other in connection with any such filing and with
resolving any investigation or other inquiry concerning the transactions
contemplated by this Agreement commenced by any Governmental Authority.


       (c)    In furtherance and not in limitation of the covenants contained in
Section 6.2 and Section 6.3 (b) hereof, each of Aether and Riverbed shall use
its reasonable best efforts to resolve such objections, if any, as may be
asserted with respect to the Merger or any other transactions contemplated by
this Agreement under any applicable law. If any administrative, judicial or
legislative action or proceeding is instituted (or threatened to be instituted)
challenging the Merger or any other transaction contemplated by this Agreement
as violative of any applicable law, each of Aether and Riverbed shall cooperate
and use its reasonable best efforts vigorously to contest and resist any such
action or proceeding, and to have vacated, lifted, reversed or overturned any
decree, judgment, injunction or other order (whether temporary, preliminary or
permanent) that is in effect and that restricts, prevents or prohibits
consummation of the Merger or any other transaction contemplated by the
Agreement.

       (d)    Each of Aether and Riverbed shall promptly inform the other of any
communications received by such party or any of its Affiliates from any
Governmental Authority regarding any of the transactions contemplated hereby.
Each of Aether and Riverbed shall advise the other promptly of any
understandings, undertakings or agreements which such party or any of its
Affiliates proposes to make or enter into with any Governmental Authority in
connection with the transactions contemplated hereby. Aether or any of its
Affiliates shall not be obligated to enter into any undertakings, understandings
or agreements with any Governmental Authority if such undertakings,
understandings or agreements are reasonably unacceptable to Aether.

       Section 6.4 Conduct of Business of Riverbed Pending the Closing. From the
date hereof through the Closing, except as expressly permitted or contemplated
by this Agreement, unless Aether shall otherwise agree in writing prior to the
taking of any action prohibited by the terms of this Section 6.4, Riverbed and
its Subsidiaries shall conduct their operations and business in the ordinary and
usual course of business and use reasonable best efforts (which shall not
include any offer to pay any retention or stay bonus without Aether's consent)
to keep available the services of its present officers and key employees and
preserve the goodwill and business relationships with all Persons having
business relationships with it. Without limiting the generality of the
foregoing, and except as otherwise expressly permitted by this Agreement, prior
to the Closing, without the prior written consent of Aether, neither Riverbed
nor any of its Subsidiaries shall:

       (a)    amend or modify its Organizational Documents;

       (b)    issue, sell, pledge or dispose of, grant or otherwise create, or
agree to issue, sell, pledge or dispose of, grant or otherwise create any
capital stock or other equity securities, any debt or other securities
convertible into or exchangeable for any of its capital stock or other equity
securities, or any Option with respect thereto, except for (i) the issuance of
Riverbed Common Stock upon conversion of the Riverbed Preferred Stock, (ii) upon
the exercise of outstanding Riverbed Options, or (iii) the issuance of up to
75,000 Options to be granted to Riverbed management with a minimum exercise
price of $13.53 per share;

                                                                              38
<PAGE>   44

      (c) purchase, redeem or otherwise acquire or retire, or offer to
purchase, redeem or otherwise acquire or retire, any of its capital stock or
other equity securities (including any Options with respect to any of its
capital stock or other equity securities and any securities convertible or
exchangeable into any of its capital stock or other equity securities) or any
long term debt;

      (d) declare, set aside, make or pay any dividend or other distribution,
payable in cash, stock, property or otherwise, with respect to any of its
capital stock or other equity securities, or subdivide, reclassify,
recapitalize, split, combine or exchange any of its capital stock or other
equity securities;

      (e) incur or become contingently liable with respect to any indebtedness
for borrowed money or guarantee any such indebtedness or issue any debt
securities, except for additional indebtedness incurred under existing debt
agreements or credit facilities, or new credit facilities;

      (f) acquire or agree to acquire by merging or consolidating with, or by
purchasing a substantial equity interest in or a substantial portion of the
assets of, or by any other manner, any business or any corporation,
partnership, association or other business entity;

      (g) mortgage or otherwise encumber or subject to any Lien other than
Permitted Liens, or sell, transfer or otherwise dispose of, any assets or
properties that are material, individually or in the aggregate, to Riverbed and
its Subsidiaries, taken as a whole, other than Liens incurred in the ordinary
course of business consistent with past practice, and sales and dispositions in
the ordinary course of business consistent with past practice;

      (h) except in the ordinary course of business consistent with past
practice (which shall include normal periodic performance reviews and related
benefit increases) or pursuant to the existing terms of any collective
bargaining agreement, Riverbed will not, nor will it permit any of the
Subsidiaries to (i) increase in any manner the compensation of any of the
officers or other employees of Riverbed or any of its Subsidiaries other than
the payment of customary year-end bonuses, which do not exceed $250,000 in the
aggregate; (ii) adopt, amend, terminate, or increase liability with respect to
any Riverbed Plan or Riverbed Benefit Arrangement or commit to do so; or (iii)
enter into, or negotiate, any collective bargaining agreement with respect to
employees of Riverbed or any of its Subsidiaries except as required by law, in
which case Riverbed or such Subsidiary shall first notify Aether;

      (i) take any action, other than reasonable actions in the ordinary course
of business, with respect to accounting policies or procedures (including Tax
accounting policies, procedures and elections relating to Taxes that would
apply to Riverbed and its Subsidiaries, Aether or the Surviving Corporation
after the Merger), except as may be required by GAAP, consistently applied, or
Law;

      (j) settle any material audit or litigation or, except as required by
Law, amend in any respect any material Tax Return;

      (k) enter into, modify, amend, extend or terminate any agreement or
agreements for goods, property rights or services with (i) any director or
officer, or any Affiliate of any such Person, or (ii) any other Person which
obligates Riverbed, or any Affiliate of Riverbed, to pay in



                                                                        39

<PAGE>   45


excess of $25,000 in any twelve (12) month period; provided, however, that
Riverbed may offer employment to individuals consistent with past practice; and

      (l) authorize any of, or commit or agree to take any of, the foregoing
actions. Section 6.5 Conduct of Business of Aether Pending the Closing. From
the date hereof through the earlier of (i) the Closing or (ii) the termination
of this Agreement, without the prior written consent of Riverbed, neither
Aether nor any of its Subsidiaries shall:

      (a) amend or modify its Organizational Documents;

      (b) issue, sell, pledge or dispose of, grant or otherwise create, or
agree to issue, sell, pledge or dispose of, grant or otherwise create any
capital stock or other equity securities, any debt or other securities
convertible into or exchangeable for any of its capital stock or other equity
securities, or any Option with respect thereto, except for (i) the issuance of
stock upon the exercise of outstanding Aether Options or (ii) the issuance of
Aether Options pursuant to an Aether stock option plan or stock purchase plan;

      (c) purchase, redeem or otherwise acquire or retire, or offer to
purchase, redeem or otherwise acquire or retire, any of its capital stock or
other equity securities (including any Options with respect to any of its
capital stock or other equity securities and any securities convertible or
exchangeable into any of its capital stock or other equity securities) or any
long term debt;

      (d) declare, set aside, make or pay any dividend or other distribution,
payable in cash, stock, property or otherwise, with respect to any of its
capital stock or other equity securities, or subdivide, reclassify,
recapitalize, split, combine or exchange any of its capital stock or other
equity securities;

      (e) acquire or agree to acquire by merging or consolidating with, or by
purchasing a substantial equity interest in or a substantial portion of the
assets of, or by any other manner, any material business or any material
corporation, partnership, association or other business entity; and

      (f) authorize any of, or commit or agree to take any of, the foregoing
actions.

      Section 6.6 Nasdaq Listing. Aether agrees to authorize for listing on
Nasdaq the shares of Aether Common Stock issuable, and those required to be
reserved for issuance, in connection with the Merger, upon official notice of
issuance. To the extent necessary, Aether agrees to file a registration
statement on Form S-8 (for persons eligible therefor) for the shares of Aether
Common Stock issuable with respect to assumed Riverbed Options within 30 days
after the Effective Time, or as soon thereafter as the securities laws permit.

      Section 6.7 Access to Information.

      (a) From the date hereof to the Effective Time, each of Riverbed and
Aether shall (and shall cause their respective Subsidiaries and Representatives
to) afford the other's Representatives with reasonable access at all reasonable
times during normal business hours to



                                                                        40

<PAGE>   46


its officers, employees, agents, properties, offices, plants and other
facilities, books, records and Tax Returns, and shall furnish such
Representatives with all financial, operating and other data and information as
may be reasonably requested.

      (b) Each of Aether, the Merger Sub and Riverbed covenants and agrees to
maintain the confidentiality of any Confidential Information, as defined
herein, it receives from any other party or such party's Subsidiaries or
Affiliates and, except as expressly permitted in this Agreement or as required
by law or in connection with judicial proceedings, shall not disclose any such
Confidential Information to third parties. A party receiving Confidential
Information from another party shall use at least the same degree of care to
maintain its confidentiality as it uses to maintain its own Confidential
Information. A party receiving Confidential Information shall not, except in
connection with this Agreement, directly or indirectly use Confidential
Information of the disclosing party without the prior written consent of such
disclosing party. As used in this Agreement, "Confidential Information"
includes, without limitation, information not previously disclosed to the
public or to the trade by a party to this Agreement relating to its products,
facilities and methods, trade secrets and other intellectual property,
software, source code, systems, procedures, manuals, confidential reports,
product price lists, customer lists, financial information (including revenues,
costs or profits associated with any product), business plans, prospects, or
opportunities, but shall exclude any information already in the public domain.

      Section 6.8 No Solicitation.

      (a) Riverbed shall not, and it shall instruct its Representatives
(including, without limitation, any investment banker, attorney or accountant
retained by Riverbed or a Subsidiary of Riverbed) not to, directly or
indirectly, for or on its behalf (i) initiate, solicit or encourage any
inquiries or proposals that constitute, or could reasonably be expected to lead
to, a proposal or offer for a merger, consolidation, or business combination of
Riverbed or any of its Subsidiaries, or the sale of assets representing a
substantial portion of the assets of Riverbed and its Subsidiaries, taken as a
whole, or the sale of shares of capital stock of Riverbed or any Subsidiary
(other than to Riverbed or a Subsidiary of Riverbed or as permitted by Section
6.4 hereto), including, without limitation, by way of a tender offer or
exchange offer by any Person other than the Transactions (any of the foregoing
inquiries or proposals being referred to in this Agreement as an "Acquisition
Proposal"), (ii) engage in negotiations or discussions concerning, or provide
to any Person or entity any Confidential Information or data relating to
Riverbed or any Subsidiary of Riverbed for the purposes of, or otherwise
cooperate with or assist or participate in, facilitate or encourage, any
inquiries or the making of any Acquisition Proposal, (iii) agree to, approve or
recommend any Acquisition Proposal, or (iv) take any other action inconsistent
with the obligations and commitments assumed by Riverbed pursuant to this
Section 6.8; provided, however, that nothing contained in this Agreement shall
prevent Riverbed or its Board of Directors from furnishing Confidential
Information to, or entering into discussions or negotiations with, any person
or entity in connection with an unsolicited bona fide written Acquisition
Proposal to Riverbed or its stockholders, if and only to the extent that (1)
the Board of Directors of Riverbed determines in good faith (after consultation
with outside legal counsel) that such action is required for such Board of
Directors to comply with its fiduciary duties to stockholders under applicable
law, and (2) prior to furnishing such Confidential Information to, or entering
into discussions or negotiations with, such person or entity, Riverbed receives
from




                                                                        41

<PAGE>   47

such person or entity an executed confidentiality agreement. Riverbed and its
Representatives will immediately cease and cause to be terminated any existing
activities, discussions or negotiations by Riverbed or its Representatives with
any parties conducted heretofore with respect to any of the foregoing. In
addition, notwithstanding the provisions of this Section 6.8, or any other
provision of this Agreement, Riverbed may withdraw, modify, or refrain from
making its recommendation in accordance with Section 6.9 .

      (b) Riverbed shall (i) promptly notify Aether in writing after receipt by
Riverbed (or its Representatives) of any Acquisition Proposal or any inquiries
indicating that any Person is considering making or wishes to make an
Acquisition Proposal, which notification shall be in writing and shall contain
the principle financial terms of any such Acquisition Proposal, and (ii)
promptly notify Aether in writing after receipt of any request for Confidential
Information relating to it or any of its Subsidiaries or for access to its or
any of its Subsidiaries' properties, books or records by any person that, to
Riverbed's Knowledge, may be considering making, or has made, an Acquisition
Proposal.

      Section 6.9 Riverbed Stockholder Meeting. Riverbed shall take all action
necessary, in accordance with the DGCL and Riverbed's Organizational Documents,
to call a meeting of its stockholders (the "Riverbed Meeting") to be held as
promptly as practicable after the date of this Agreement but not later than
February 25, 2000 and before terminating this Agreement to accept an
Acquisition Proposal for the purpose of considering and voting upon this
Agreement and the Merger (the "Riverbed Stockholder Approval"). The Board of
Directors of Riverbed shall recommend that the stockholders of Riverbed approve
this Agreement and the Merger; provided, however, that the Board of Directors
of Riverbed, by action of a majority of the entire Board of Directors of
Riverbed, may withdraw, modify or refrain from making such recommendation if
such Board of Directors determines in good faith, after receipt of an
Acquisition Proposal and after consultation with outside legal counsel, that
the withdrawal or modification of or failure to make such recommendation is
required for such Board of Directors to comply with its fiduciary duties under
applicable law.

      Section 6.10 Preparation of the Disclosure Statements. Riverbed will, as
promptly as practicable, prepare the disclosure statements in connection with
the vote of the stockholders of Riverbed in respect of the Merger. At the
request of Riverbed and as soon as practicable, Aether shall provide Riverbed
with all information deemed necessary in order for Riverbed and Aether to
satisfy their disclosure obligations under the Securities Act in connection
with the Riverbed Stockholder Meeting, and Aether will cooperate with Riverbed
in the preparation of such disclosure statements.Section 6.11 Cooperation with
Accountants. Riverbed shall cooperate with KPMG, Aether's independent auditors,
in connection with their audit of the financial statements of Riverbed and
provide customary and reasonable representations and other documents reasonably
requested by Aether in connection with KPMG's audit of Riverbed's financial
statements.

      Section 6.12 Public Announcements. At all times at or before the Closing,
neither Riverbed nor Aether shall issue or make, directly or indirectly, any
reports, statements or releases to the public with respect to this Agreement or
the Transactions contemplated hereby without the prior written consent of the
other, which consents shall not be unreasonably withheld or delayed; provided,
however, that Riverbed and Aether may, without the prior written consent of the
other, issue or make, directly or indirectly, any report, statement or release
required by



                                                                        42

<PAGE>   48


Law (including without limitation filings with the Securities Exchange
Commission in connection with Aether's offering of securities), its fiduciary
obligations or any listing agreement or arrangement to which such Person is a
party with a national securities exchange or national market system if the
other parties to this Agreement are so notified as soon as possible in advance
of such report, statement or release and, to the extent practicable, given a
reasonable opportunity to review and comment on the report, statement or
release. The parties will agree to the text of the press releases announcing
the signing of the Agreement.

      Section 6.13 Blue Sky. Aether shall use its commercially reasonable
efforts to obtain prior to the Effective Time all approvals or permits required
to carry out the transactions contemplated hereby under applicable Blue Sky
Laws in connection with the issuance of shares of Aether Common Stock in the
Merger and as contemplated by this Agreement; provided, however, that with
respect to such qualifications neither Aether nor Riverbed shall be required to
register or qualify as a foreign corporation or to take any action which would
subject it to general service of process or taxation in any jurisdiction where
any such entity is not now so subject.

      Section 6.14 Registration Rights. Prior to the Effective Time, Aether
shall execute and deliver the Registration Rights Agreement. Aether has
informed Riverbed that its intends to file a registration statement registering
shares of Aether Common Stock within thirty (30) days after the Effective Time.
In connection with the filing of such registration statement, Aether covenants
and agrees to permit the stockholders of Riverbed to participate pro rata among
all the stockholders selling stock in the offering (except that NexGen
Technologies, L.L.C. shall be permitted to sell shares in preference to
Aether's other stockholders if the underwriters exercise their overallotment
option) in accordance with the number of shares of Aether Common Stock held by
each such stockholder (assuming the shares of Aether Common Stock had been
issued in the Merger).

      Section 6.15 General Indemnification. Each party (the "Indemnifying
Party") covenants and agrees to indemnify, defend, protect and hold harmless
the other parties and their respective officers, directors, employees,
stockholders, assigns, successors and affiliates (individually, an "Indemnified
Party" and collectively, "Indemnified Parties") from, against and in respect
of:

      (a) all liabilities, losses, claims, damages, punitive damages, causes of
action, lawsuits, administrative proceedings (including informal proceedings),
investigations, audits, demands, assessments, adjustments, judgments,
settlement payments, deficiencies, penalties, fines, interest (including
interest from the date of such damages) and costs and expenses (including
without limitation reasonable attorneys' fees and disbursements of every kind,
nature and description) (collectively, "Damages") suffered, sustained, incurred
or paid by the Indemnified Parties in connection with, resulting from or
arising out of, directly or indirectly:

           (i)       any breach of any representation or warranty of the
                     Indemnifying Party set forth in this Agreement or any
                     schedule or certificate, delivered by or on behalf of the
                     Indemnifying Party in connection herewith; or

           (ii)      any nonfulfillment of any covenant or agreement on the
                     part of the Stockholders of the Indemnifying Party or,
                     prior to the Effective Time, the Indemnifying Party, in
                     this Agreement; or


                                                                        43

<PAGE>   49


           (iii)     the failure of the Merger to be treated as a
                     reorganization under Sections 368(a)(1)(A) and
                     368(a)(2)(E) of the Code as the result of, directly or
                     indirectly, the actions or omissions of the Indemnifying
                     Party or the Indemnifying Party's Stockholders, provided,
                     however that the holders of shares of Riverbed Capital
                     Stock immediately prior to the Effective Time shall not be
                     considered Aether Stockholders for purposes of this
                     Section 6.15(a)(iii); and

      (b) any and all Damages incident to any of the foregoing or to the
enforcement of this Section 6.15.

      Section 6.16 Stockholder's Representative.

      (a) Upon the Effective Time and without further act of any Stockholder,
the Stockholders' Representative shall be appointed as agent and
attorney-in-fact for each Stockholder, for and on behalf of each such
Stockholder, with full power and authority to represent the Stockholders and
their successors with respect to all matters arising under this Agreement and
the Escrow Agreement, and all actions taken by the Stockholders' Representative
hereunder shall be binding upon such Stockholders and their successors as if
expressly ratified and confirmed in writing by each of them. Without limiting
the generality of the foregoing, the Stockholders' Representative shall have
full power and authority, on behalf of all the Stockholders and their
successors, to interpret all the terms and provisions of this Agreement, to
dispute or fail to dispute any Claim of Damages against the Escrow Shares made
by an Indemnified Party, to assert Claims of Damages against any Indemnifying
Party, to negotiate and compromise any dispute which may arise under this
Agreement, to sign any releases or other documents with respect to any such
dispute, and to authorize delivery of Escrow Shares pursuant to the Escrow
Agreement or any other payments to be made with respect thereto. All
determinations of the Stockholders' Representative shall be decided by a
majority thereof in the event there is more than one Stockholders'
Representative.

      (b) The Stockholders' Representative, or any successor hereafter
appointed, may resign and shall be discharged of his duties hereunder upon the
appointment of a successor Stockholders' Representative as hereinafter
provided. In case of such resignation, or in the event of the death or
inability to act of the Representative, a successor shall be named from among
the Stockholders by a majority of the members of the Board of Directors of who
served on such board prior to the Merger. Each such successor Stockholders'
Representative shall have all the power, authority, rights and privileges
hereby conferred upon the original Stockholders' Representative, and the term
"Stockholders' Representative" as used herein shall be deemed to include such
successor Stockholders' Representative.

      (c) In performing any of their duties under this Agreement, or upon the
claimed failure to perform his duties hereunder, the Stockholders'
Representative shall not be liable to the Stockholders for any damages, losses
or expenses which they may incur as a result of any act, or failure to act
under this Agreement or the Escrow Agreement; provided, however, that the
Representative shall be liable for damages arising out of actions or omissions
that both (i) were taken or omitted not in good faith and (ii) constituted
willful default or gross negligence under this Agreement or the Escrow
Agreement. Accordingly, the Representative shall not incur any such Liability
with respect to (i) any action taken or omitted to be taken in good faith upon


                                                                        44

<PAGE>   50


advice of his counsel given with respect to any questions relating to the
duties and responsibilities of the Stockholders' Representative hereunder; or
(ii) any action taken or omitted to be taken in reliance upon any document,
including any written notice or instructions provided for in this Agreement or
the Escrow Agreement, not only as to its due execution and to the validity and
effectiveness of its provisions, but also as to the truth and accuracy of any
information contained therein, which the Stockholders' Representative shall in
good faith believe to be genuine, to have been signed or presented by the
purported proper person or persons and to conform with the provisions of this
Agreement and the Escrow Agreement. The limitation of liability provisions of
this Section shall survive the termination of this Agreement and the
resignation of the Representative. The stockholders of Riverbed shall severally
indemnify the Stockholders' Representative and hold him harmless against any
loss, liability or expense (including any expenses of legal counsel retained by
the Stockholders' Representative) incurred without willful default, gross
negligence or bad faith on the part of the Stockholders' Representative and
arising out of or in connection with the acceptance or administration of his
duties hereunder

      Section 6.17 Indemnification Procedures. All claims for indemnification
under Section 6.15 ("Claims") shall be asserted and resolved as follows:

      (a) In the event that any Indemnified Party has a Claim against any
Indemnifying Party which does not involve a Claim being asserted against or
sought to be collected by a third party, the Indemnified Party shall with
reasonable promptness send a Claim Notice with respect to such Claim to the
Stockholders' Representative if the Indemnified Party is an Aether Indemnified
Party or Aether if the Indemnified Party is a Riverbed Indemnified Party. The
Indemnified Party's failure to give prompt notice or to provide copies of
documents or to furnish relevant data shall not constitute a defense (in whole
or in part) to any claim by the Indemnified Party against the Indemnifying
Party for indemnification, except and only to the extent that such failure
shall have caused or increased such liability or adversely affected the ability
of the Indemnifying Party to defend against or reduce its liability. In case an
objection is made in writing in accordance with this Section 6.17, the
Indemnified Party shall have thirty (30) days to respond in a written statement
to the objection. If after such thirty (30) day period there remains a dispute
as to any Claims, the parties shall attempt in good faith for sixty (60) days
to agree upon the rights of the respective parties with respect to each of such
Claims. If the parties should so agree, a memorandum setting forth such
agreement shall be prepared and signed by both parties. The actions and
decisions of the Stockholders' Representative shall be binding upon all
Stockholders.

      (b) In the event that any Claim for which the Indemnifying Party would be
liable to an Indemnified Party hereunder is asserted against an Indemnified
Party by a third party, the Indemnified Party shall with reasonable promptness
notify the Stockholders' Representative if the Indemnified Party is an Aether
Indemnified Party or Aether if the Indemnified Party is a Riverbed Indemnified
Party of such Claim, specifying the nature of such Claim and the amount or the
reasonably estimated amount thereof to the extent then feasible (which estimate
shall not be conclusive of the final amount of such Claim) (the "Claim
Notice"). The Indemnifying Party (or its representative) shall have 30 days
from the receipt of the Claim Notice (the "Notice Period") to notify the
Indemnified Party (i) whether or not such party disputes the liability to the
Indemnified Party hereunder with respect to such Claim and (ii) if such party
does not dispute



                                                                        45

<PAGE>   51

such liability, whether or not the Indemnifying Party desires, at the sole cost
and expense of the Indemnifying Party, to defend against such Claim, provided
that such party is hereby authorized (but not obligated) prior to and during
the Notice Period to file any motion, answer or other pleading and to take any
other action which the Indemnifying Party shall deem necessary or appropriate
to protect the Indemnifying Party's interests. In the event that Indemnifying
Party (or its representative) notifies the Indemnified Party within the Notice
Period that the Indemnifying Party does not dispute the Indemnifying Party's
obligation to indemnity hereunder and desires to defend the Indemnified Party
against such Claim and except as hereinafter provided, such party shall have
the right to defend by appropriate proceedings, which proceedings shall be
promptly settled or prosecuted by such party to a final conclusion, provided
that such party may not settle any matter (in whole or in part) without the
prior written consent of the Indemnified Party (which shall not be unreasonably
withheld) and unless such settlement includes a complete and unconditional
release of the Indemnified Party. If the Indemnified Party desires to
participate in, but not control, any such defense or settlement the Indemnified
Party may do so at its sole cost and expense. If the Indemnifying Party elects
not to defend the Indemnified Party against such Claim, whether by failure of
such party to give the Indemnified Party timely notice as provided above or
otherwise, then the Indemnified Party, without waiving any rights against such
party, may settle or defend against any such Claim in the Indemnified Party's
sole discretion and the Indemnified Party shall be entitled to recover from the
Indemnifying Party the amount of any settlement or judgment and, on an ongoing
basis, all indemnifiable costs and expenses of the Indemnified Party with
respect thereto, including interest from the date such costs and expenses were
incurred. The actions and decisions of the Stockholders' Representative shall
be binding upon all of the persons entitled to the Merger Consideration.

      (c) If at any time, in the reasonable opinion of the Indemnified Party,
notice of which shall be given in writing to the Stockholders' Representative
if the Indemnified Party is an Aether Indemnified Party or Aether if the
Indemnified Party is a Riverbed Indemnified Party, any such Claim seeks or will
likely result in material prospective or other relief which could have a
Material Adverse Effect on the assets, liabilities (including without
limitation Tax liabilities), financial condition or results of operations of
any Indemnified Party or Merger Sub or any Subsidiary, the Indemnified Party
shall have the right to control or assume (as the case may be) the defense of
any such Claim and the amount of any judgment or settlement and the reasonable
costs and expenses of defense shall be included as part of the indemnification
obligations of the Indemnifying Party hereunder, provided that such party may
not settle any matter (in whole or in part) without the prior written consent
of the Indemnified Party (which shall not be unreasonably withheld) unless such
settlement includes a complete and unconditional release of the Indemnifying
Party. If the Indemnified Party should elect to exercise such right, the
Stockholders' Representative if the Indemnified Party is an Aether Indemnified
Party or Aether if the Indemnified Party is a Riverbed Indemnified Party shall
have the right to participate in, but not control, the defense of such claim or
demand at the sole cost and expense of the Indemnifying Party.


      (d) Nothing herein shall be deemed to prevent an Indemnified Party from
making a claim, and an Indemnified Party may make a claim hereunder, for
potential or contingent claims or demands provided the Claim Notice sets forth
the specific basis for any such potential or



                                                                        46

<PAGE>   52


contingent claim or demand to the extent then feasible and the Indemnified
Party has reasonable grounds to believe that such a claim or demand may be
made.

      (e) The Indemnified Party's failure to give reasonably prompt notice as
required by this Section 6.17 of any actual, threatened or possible claim or
demand which may give rise to a right of indemnification hereunder shall not
relieve the Indemnifying Party of any liability which the Indemnifying Party
may have to the Indemnified Party unless the failure to give such notice
materially and adversely prejudiced the Indemnifying Party.

      (f) The parties will make appropriate adjustments for any Tax benefits,
Tax detriments or insurance proceeds in determining the amount of any
indemnification obligation under Section 6.15, provided that no Indemnified
Party shall be obligated to continue pursuing any payment pursuant to the terms
of any insurance policy.

      Section 6.18 Exclusive Remedy.

      (a) Aether and its Subsidiaries shall not be entitled to any
indemnification for Damages under this Agreement, unless and until the
aggregate amount of Damages exceeds $1,000,000, in which case Aether shall only
be entitled to the amount of Damages in excess of $1,000,000. Aether's sole and
exclusive right to compensation for the indemnification obligations set forth
in this Agreement or otherwise shall be limited to claims against the Escrow
Shares and Aether shall have no right to pursue any Claims under this Agreement
or otherwise against any former holder of Riverbed Capital Stock. For purposes
of the preceding sentence, the value of the Escrow Shares used to satisfy
payments of amounts owed to Aether shall be the Average Aether Stock Price for
the five Trading Days prior to the date of any payment of Escrow Shares to
offset amounts pursuant to this Section 6.18.

      (b) Riverbed and its Subsidiaries shall not be entitled to any
indemnification for Damages under this Agreement, unless and until the
aggregate amount of Damages exceeds $1,000,000, in which case Riverbed shall
only be entitled to the amount of Damages in excess of $1,000,000. Riverbed's
sole and exclusive right to compensation for the Indemnification set forth in
this Agreement shall be limited to an amount not to exceed $40,467,600 (which
amount equals the product of 270,000 multiplied by $149.88).

      (c) After the Closing, to the extent permitted by Law, the indemnities
set forth in Section 6.15 and Section 6.17 shall be the exclusive remedies of
the parties hereto and their respective officers, directors, employees, agents
and Affiliates for any misrepresentation, breach of warranty or breach of any
covenant or agreement contained in this Agreement, and the parties shall not be
entitled to a rescission of this Agreement or any further indemnification
rights or claims of any nature whatsoever in respect thereof, all of which the
parties hereto hereby waive

      (d) Each Riverbed director, officer and stockholder waives any right of
contribution, indemnification or other similar right against Merger Sub or
Aether arising out of any Claim for indemnification under this Agreement. Upon
the Closing, Riverbed's rights to indemnification pursuant to Section 6.15
shall automatically be assigned to the Stockholders.

      (e) An Indemnified Party's right to indemnification under the Agreement
shall terminate on the later to occur of (i) the first anniversary of the
Closing Date or (ii) with respect


                                                                        47

<PAGE>   53


to a Claim made prior to the first anniversary of the Closing Date, the
resolution of such Claim pursuant to Section 6.17 or as otherwise provided in
the Escrow Agreement.

      Section 6.19 Directors' and Officers' Indemnification and Insurance.

      (a) From and after the Effective Time, subject to the limitations set
forth in the first sentence of Section 6.18(d), the Surviving Corporation
shall, Section 6.15, indemnify, defend and hold harmless the present and former
officers and directors of Riverbed and its Subsidiaries (the "Indemnified
Officers/Directors") against all losses, expenses (including attorneys fees),
claims, damages, liabilities or amounts ("Losses") that are paid in settlement
(provided that such settlement has been approved by Aether, such approval not
to be unreasonably withheld) of, or otherwise in connection with, any claim,
action, suit, proceeding or investigation, based in whole or in part on the
fact that such person is or was a director or officer of Riverbed and arising
out of actions or omissions occurring at or prior to the Effective Time
(including, without limitation, the Transactions), in each case, to the full
extent permitted under the DGCL and Riverbed's articles of incorporation and
bylaws (to the extent permitted by applicable law), and under any agreements as
in effect on the date of this Agreement (true and correct copies of which have
been previously provided to Aether) (including rights to reimbursement or
advancement of expenses and exculpation from liability).

      (b) The Surviving Corporation shall keep in effect provisions in its
articles of incorporation and bylaws providing for exculpation of director
liability and its indemnification of the Indemnified Officers/Directors to the
fullest extent permitted under the DGCL, which provisions shall not be amended
except as required by applicable law or except to make changes permitted by law
that would enlarge the right of indemnification of the Indemnified
Officers/Directors, provided, however, that the certificate of incorporation,
bylaws and any indemnification agreements shall not provide for exculpation of
director liability and indemnification of the Indemnified Officers/Directors
for Claims under the Agreement which are conclusively determined to be
satisfied by the Escrow Shares and Escrow Proceeds (though until such time that
such Claim is conclusively determined, advancement of expenses by the Surviving
Corporation will be required to the extent required under the Organizational
Documents and indemnification agreements). The Surviving Corporation shall keep
in effect and comply with the terms and conditions of the indemnification
agreements between Riverbed and each of its directors in effect as of the date
of this Agreement.

      (c) For a period of three years after the Effective Time, the Surviving
Corporation shall maintain in effect the current policies of directors' and
officers' liability insurance maintained by Riverbed, a true and correct
summary of which is set forth on Schedule 6.19 to the Disclosure Letter, or
policies providing substantially the same coverage, covering persons who are
currently covered by Riverbed's officers' and directors' liability insurance
policies with respect to actions or omissions occurring at or prior to the
Effective Time, to the extent that such policies are available; provided,
however, that policies of at least the same coverage containing terms and
conditions which are no less advantageous to the insureds may be substituted
therefor, but, in no event shall the Surviving Corporation be required to spend
more than an amount per year equal to 150% of the current annual premiums paid
by Riverbed for such insurance.



                                                                        48

<PAGE>   54


      (d) The provisions of this Section 6.19 shall survive the consummation of
the Merger and expressly are intended to benefit each of the Indemnified
Officers/Directors.


      Section 6.20 Tax-Free Reorganization. Aether, Merger Sub and Riverbed
each acknowledges and agrees that (i) it intends the Merger to constitute a
reorganization within the meaning of Section 368(a)(2)(E) of the Code and (ii)
to the extent permissible by law, each will report the Merger as such a
reorganization in any and all federal, state and local income Tax returns filed
by it. No party shall take any action either prior to or after the Closing Date
that results in the Merger failing to qualify as a "reorganization" under
Section 368(a) (2)(E) of the Code. Aether, Merger Sub and Riverbed will each
execute and deliver to Wilmer, Cutler & Pickering and Shaw Pittman the tax
representation letters described in Section 7.1(g).

      Section 6.21 Board Representation. The Board of Directors of Aether will
take all actions reasonably necessary to cause the Aether's Board of Directors,
immediately after the Effective Time, to consist of 12 persons, two of whom
shall have been designated by the Board of Directors of the Riverbed prior to
the Effective Time (including E. Wayne Jackson III). If, prior to the Effective
Time, any of the designees of Riverbed shall decline or be unable to serve as a
director of Aether immediately after the Merger, Riverbed shall designate
another person to serve in such person's stead.

      Section 6.22 Notification of Certain Matters. Riverbed shall give prompt
notice to Aether and Merger Sub, and Aether and Merger Sub shall give prompt
notice to Riverbed, of (i) the occurrence or nonoccurrence of any event the
occurrence or nonoccurrence of which would be likely to cause any
representation or warranty contained in this Agreement to be untrue or
inaccurate in any material respect at or prior to the Effective Time, (ii) any
material failure of the Riverbed, Aether or Merger Sub, as the case may be, to
comply with or satisfy any covenant, condition or agreement to be complied with
or satisfied by it hereunder, (iii) any notice or other communication from any
third party alleging that the consent of such third party is or may be required
in connection with the transactions contemplated by this Agreement, or (iv) any
facts or circumstances arise that could reasonably be expected to result in a
Material Adverse Effect.



                                                                        49


<PAGE>   55




                                  ARTICLE VII.

                            CONDITIONS TO THE MERGER

      Section 7.1 Conditions to Each Party's Obligation to Effect the Merger.
The respective obligations of each party to this Agreement to effect the Merger
shall be subject to the following conditions:

      (a) All consents, approvals and action of any Governmental Authority
required to permit the consummation of the Transactions shall have been
obtained or made, free of any condition that would have a Material Adverse
Effect on Aether or Riverbed.

      (b) No action shall have been taken, and no statute, rule, regulation,
executive order, judgment, decree, or injunction (other than a temporary
restraining order) shall have been enacted, entered, promulgated or enforced
(and not repealed, superseded, lifted or otherwise made inapplicable), by any
court of competent jurisdiction or Governmental Authority which restrains,
enjoins or otherwise prohibits the consummation of the Merger (each party
agreeing to use its commercially reasonable efforts to avoid the effect of any
such statute, rule, regulation or order or to have any such order, judgment,
decree or injunction lifted).

      (c) Any applicable waiting period under the HSR Act shall have expired or
been terminated.

      (d) Riverbed shall have received the Riverbed Stockholder Approval.

      (e) The Registration Rights Agreement shall have been executed by each of
the parties to it.

      (f) The parties hereto and the Escrow Agent shall have entered into the
Escrow Agreement and 270,000 shares of Aether Common Stock shall have been
deposited with the Escrow Agent.

      (g) Aether, Merger Sub and Riverbed shall have agreed on customary tax
representation letters to be delivered to Wilmer, Cutler & Pickering for
purposes of the opinion described in Section 7.3(j) and to Shaw Pittman for
purposes of the opinion set forth in Section 7.2(f).

      Section 7.2 Conditions to Obligations of Riverbed to Effect the Merger.
The obligations of Riverbed to effect the Merger are subject to the
satisfaction of the following conditions, unless waived by Riverbed:

      (a) The representations and warranties of Aether and Merger Sub contained
herein shall be true and accurate at and as of the Effective Time as though
made at the Effective Time (except to the extent a representation or warranty
speaks specifically as of an earlier date or has become untrue or inaccurate
because of Transactions contemplated herein).


                                                                        50

<PAGE>   56



      (b) Aether and Merger Sub shall have, in all material respects, performed
all obligations and complied with all covenants required by this Agreement to
be performed or complied with by them prior to the Effective Time.

      (c) Aether shall have delivered to Riverbed a certificate, dated the
Effective Time and signed by its Chief Executive Officer or Chief Financial
Officer evidencing compliance with Section 7.2(a) and (b).

      (d) Riverbed shall have received an opinion of Wilmer, Cutler &
Pickering, counsel to Aether and Merger Sub, in form and substance reasonably
satisfactory to Riverbed, addressing the matters set forth in Exhibit B.

      (e) The Average Aether Stock Price for the five Trading Days preceding
the Closing will be at least $50.00.

      (f) Riverbed shall have received an opinion from Shaw Pittman in form and
substance reasonably satisfactory to Riverbed dated as of the Closing Date and
to the effect that the Merger will be treated as a reorganization within the
meaning of Section 368(a) of the Code.

      (g) Aether shall not have experienced any Material Adverse Effects;
provided, however, Aether shall not be deemed to have experienced a Material
Adverse Effect solely as a result of a decline or drop in the trading price of
Aether Common Stock, and Riverbed shall have received a certificate signed on
behalf of Aether dated the Closing Date to such effect.

      Section 7.3 Conditions to Obligations of Aether and Merger Sub to Effect
the Merger. The obligations of Aether and Merger Sub to effect the Merger are
subject to the satisfaction of the following conditions, unless waived by
Aether and Merger Sub:

      (a) The representations and warranties of each of Riverbed and its
Subsidiaries contained herein shall be true and accurate at and as of the
Effective Time as though made at the Effective Time (except in each case to the
extent a representation or warranty speaks specifically as of an earlier date
or has become untrue or inaccurate because of Transactions contemplated
herein).

      (b) Riverbed shall have performed all obligations and complied with all
covenants required by this Agreement to be performed or complied with by it
prior to the Effective Time.

      (c) Riverbed shall have delivered to Aether a certificate, dated the
Effective Time and signed by its Chief Executive Officer or Chief Financial
Officer, evidencing compliance with Section 7.3(a) and (b).

      (d) Aether and Merger Sub shall have received an opinion of Shaw Pittman,
counsel to Riverbed, in form and substance reasonably satisfactory to Aether
and Merger Sub, addressing the matters set forth in Exhibit C.

      (e) Shareholders of Riverbed representing a sufficient percentage of
Riverbed's voting securities to approve the merger shall have executed Voting
Agreements which shall have been received by Aether and which shall be in full
force and effect and shall not have

                                                                        51

<PAGE>   57



been modified or terminated without the written consent of Aether.

      (f) Wayne Jackson and David Rensin shall have confirmed in writing to
Aether, through an Employment Agreement or otherwise, (i) that they are thereby
waiving (A) any treatment of the Merger as a "Change of Control" for purposes
of their Options and (B) any argument that their employment by Riverbed after
the Closing in the positions of Chief Executive Officer or Chief Technology
Officer, respectively, is or could be a "material reduction in job
responsibilities" for purposes of any employment or option agreement, and (ii)
that they remain bound by the restrictive covenants in their Option agreements
and other Riverbed employment and terms and conditions agreements after
consummation of the Merger as though no Merger had occurred.

      (g) The Palm Computing Contracts shall be in full force and effect.

      (h) Riverbed shall not have experienced any Material Adverse Effects and
Aether shall have received a certificate signed on behalf of Riverbed dated the
Closing Date to such effect.

      (i) A Confirmation and Non-Compete Agreement shall have been executed by
Noblestar Systems Corporation.

      (j) Aether and Merger Sub shall have received an opinion from Wilmer,
Cutler & Pickering in form and substance reasonably satisfactory to Aether and
Merger Sub dated as of the Closing Date and to the effect that the Merger will
be treated as a reorganization within the meaning of Section 368(a) of the
Code.


                                                                        52


<PAGE>   58




                                 ARTICLE VIII.

                   TERMINATION, WAIVER, AMENDMENT AND CLOSING

      Section 8.1 Termination. This Agreement may be terminated and abandoned
at any time prior to the Effective Time, whether before or after approval of
this Agreement or the Merger by the stockholders of Riverbed:

      (a) by the mutual written consent of Riverbed and Aether;

      (b) by Riverbed or Aether, if (i) the Effective Time shall not have
occurred on or before 5:00 p.m. Washington, D.C. time on the date thirty (30)
days after the date on which the last required HSR Filing is made, (ii) any
Governmental Authority, the consent of which is a condition to the obligations
of Riverbed and Aether to consummate the Transactions, shall have determined
not to grant its consent and all appeals of such determination shall have been
taken and have been unsuccessful or (iii) any court of competent jurisdiction
shall have issued an order, judgment or decree (other than a temporary
restraining order) restraining, enjoining or otherwise prohibiting the Merger
and such order, judgment or decree shall have become final and nonappealable;
provided, however, that the right to terminate this Agreement pursuant to
clause (i) shall not be available to any party whose failure to fulfill any
obligation under this Agreement has been the cause of, or resulted in, the
failure of the Effective Time to occur on or before such date;

      (c) by Riverbed, if there has been a breach by Aether of any
representation, warranty, covenant or agreement set forth in this Agreement,
which breach has not been cured within ten (10) Business Days following receipt
by Aether of notice of such breach from Riverbed; provided, however, that the
right to terminate this Agreement pursuant to this Section 8.1(c) shall not be
available to Riverbed if Riverbed, at such time, is in breach of any
representation, warranty, covenant or agreement set forth in this Agreement;

      (d) by Aether, if there has been a breach by Riverbed of any
representation, warranty, covenant or agreement set forth in this Agreement,
which breach has not been cured within ten (10) Business Days following receipt
by Riverbed of notice of such breach from Aether; provided, however, that the
right to terminate this Agreement pursuant to this Section 8.1(d) shall not be
available to Aether if Aether, at such time, is in breach of any
representation, warranty, covenant or agreement set forth in this Agreement;

      (e) by Aether or Riverbed if, at the Riverbed Meeting (including any
adjournment or postponement thereof) called pursuant to Section 6.9 hereof, the
Riverbed Stockholder Approval shall not have been obtained; and

      (f) by Riverbed pursuant to the provisions of Section 6.8 for the
purposes of pursuing an Acquisition Proposal.

      Section 8.2 Effect of Termination. In the event of termination of this
Agreement by Riverbed or Aether as provided in Section 8.1 hereof, this
Agreement shall forthwith become



                                                                        53

<PAGE>   59



void (except Section 6.7(b), Section 8.2, Section 8.5, Section 9.1, Section
9.2, Section 9.4, Section 9.5, Section 9.6, Section 9.8, Section 9.9, Section
9.10, Section 9.11, Section 9.14, or Section 9.15) and there shall be no
liability on the part of Riverbed, Aether, Merger Sub or their respective
officers, directors, or stockholders except for any breach of a party's
obligations under Section 6.7(b), Section 8.2, Section 8.5, Section 9.1,
Section 9.2, Section 9.4, Section 9.5, Section 9.6, Section 9.7, Section 9.8,
Section 9.9, Section 9.10, Section 9.11, Section 9.14, or Section 9.15).
Notwithstanding the foregoing, no party hereto shall be relieved from liability
for any willful breach of this Agreement.

      Section 8.3 Amendment or Supplement. It is understood and agreed that,
from time to time prior to the Closing, Aether and Riverbed may amend or
supplement the Schedules to the Disclosure Letter with respect to any matter
that is required to be set forth or described in such a Schedule or that is
necessary to complete or correct any information in any representation or
warranty of such party contained in this Agreement; provided, that such
amendment or supplement may only be made if a party did not have Knowledge of
such matter prior to the date of the disclosure to be amended or supplemented,
and provided further that the disclosure provided in any such amended
supplemented or revised Schedule shall in no way affect or be deemed to limit a
party's ability to terminate this Agreement and the transactions prior to the
Closing.

      Section 8.4 Extension of Time, Waiver, Etc.  At any time prior to the
Effective Time:

      (a) Aether may extend the time for the performance of any of the
obligations or acts of Riverbed, and Riverbed may extend the time for the
performance of any of the obligations or acts of Aether or Merger Sub;

      (b) Aether may waive any inaccuracies in the representations and
warranties of Riverbed contained herein or in any document delivered pursuant
hereto, and Riverbed may waive any inaccuracies in the representations and
warranties of Aether contained herein or in any document delivered pursuant
hereto; or

      (c) Aether may waive compliance with any of the agreements of Riverbed
contained herein, and Riverbed may waive compliance with any of the agreements
of Aether or Merger Sub contained herein; provided, however, that no failure or
delay by Riverbed or Aether in exercising any right hereunder shall operate as
a waiver thereof nor shall any single or partial exercise thereof preclude any
other or further exercise thereof or the exercise of any other right hereunder.

      Section 8.5 Termination Fee.

      (a) If this Agreement is terminated pursuant to Section 8.1(e) or Section
8.1(f), then Riverbed will immediately pay to Aether a termination fee equal to
$20,000,000 in cash and the reasonable out-of-pocket expenses (not to exceed
$1,000,000) incurred by Aether in connection with this Agreement, which shall
be payable immediately upon termination of this Agreement.



                                                                        54

<PAGE>   60


      (b) The agreement contained in this Section 8.5 is an integral part of
the Transactions and constitutes liquidated damages in the event of the
occurrence of the circumstances specified in Section 8.5(a) above and not a
penalty.



                                                                        55



<PAGE>   61




                                  ARTICLE IX.

                                 MISCELLANEOUS

      Section 9.1 Governing Law.

      (a) This Agreement and the legal relations among the parties hereto shall
be governed by and construed and enforced in accordance with the laws of the
State of Delaware without regard to its principles of conflicts of law.

      (b) Each party to this Agreement shall have the right to enforce
specifically the terms and provisions of this Agreement in any court of the
United States located in the State of Delaware or in Delaware state court, this
being in addition to any other remedy to which they are entitled at law or in
equity or under this Agreement. In addition, each of the parties hereto (i)
consents to submit such party to the personal jurisdiction of any Federal court
located in the State of Delaware or any Delaware state court in the event any
dispute arises out of this Agreement or any of the transactions contemplated
hereby, (ii) agrees that such party will not attempt to deny or defeat such
personal jurisdiction by motion or other request for leave from any such court
and (iii) agrees that such party will not bring any action relating to this
Agreement or any of the transactions contemplated hereby in any court other
than a court of the United States located in the State of Delaware or a
Delaware state court. It is further agreed that any breaching or defaulting
party hereunder shall pay to the other parties hereto such out of pocket costs
and expenses, including legal and accounting fees, as are reasonably incurred
in pursuit of such parties' remedies hereunder.

      Section 9.2 Entire Agreement. This Agreement, including the exhibits and
schedules attached hereto, constitutes the entire agreement among the parties
pertaining to the subject matter hereof and supersedes all prior agreements,
understandings, letters of intent, negotiations and discussions, whether oral
or written, of the parties, including without limitation any discussions,
commitments or agreements between the parties concerning Riverbed equity
issuances or debt financings, and there are no warranties, representations or
other agreements, express or implied, made to any party by any other party in
connection with the subject matter hereof except as specifically set forth
herein or in the documents delivered pursuant hereto or in connection herewith.

      Section 9.3 Modification; Waiver. No supplement, modification, extension,
waiver or termination of this Agreement shall be binding unless executed in
writing by the party to be bound thereby. No waiver of any provision of this
Agreement shall be deemed or shall constitute a waiver of any other provision
hereof (whether or not similar), nor shall such waiver constitute a continuing
waiver unless otherwise expressly provided.

      Section 9.4 Notices. All notices, consents, requests, reports, demands or
other communications hereunder (collectively, "Notices") shall be in writing
and may be given personally, by registered mail, fax or by Federal Express (or
other reputable overnight delivery service):



                                                                        56

<PAGE>   62


            if to Aether or Merger Sub, to it at:

            Aether Systems, Inc.
            11460 Cronridge Drive
            Owings Mills, Maryland 21117
            Attention:  David S. Oros, Chief Executive Officer.
            Tel:  410-654-6400
            Fax:  410-654-6554

            with a copy to:

            Wilmer, Cutler & Pickering
            2445 M Street, N.W.
            Washington, D.C. 20037
            Attention:  Mark Dewire, Esq.
            Tel:  (202) 663-6000
            Fax: (202) 663-6363

            if to Riverbed, to it at:

            Riverbed Technologies, Inc.
            2070 Chain Bridge Road, Suite 475
            Vienna, Virginia
            Attention:  Wayne Jackson
            Tel: (703) 847-3303
            Fax:  (703) 847-3306

            with a copy to:

            Shaw Pittman
            1676 International Drive - PH
            McLean, Virginia 22102
            Attention:  Lawrence T. Yanowitch, Esq.
                        John M. McDonald, Esq.
            Tel: (703) 790-7790
            Fax: (703) 790-7901

or to such other address or such other person as the addressee party shall have
last designated by notice to the other party. All Notices shall be deemed to
have been given (i) when delivered personally, (ii) three (3) days after being
sent by registered mail with proper postage prepaid, (iii) upon transmission by
fax and receipt of confirmation of such transmission by the sender's fax
machine, or (iv) one day after being sent by Federal Express (or other
reputable overnight delivery service) with proper postage prepaid.

      Section 9.5 Expenses. Whether or not the transactions contemplated by
this Agreement shall be consummated, all fees and expenses incurred by any
party hereto in connection with this Agreement shall, subject to Section 8.5
and unless Aether elects to pay all or a portion of such expenses, be borne by
such party.



                                                                        57

<PAGE>   63


      Section 9.6 Assignment. No party hereto shall have the right, power or
authority to assign or pledge this Agreement or any portion of this Agreement,
or to delegate any duties or obligations arising under this Agreement,
voluntarily, involuntarily, or by operation of law, without the prior written
consent of the other parties hereto.

      Section 9.7 Survival of Representations, Warranties and Covenants. All
representations, warranties and covenants made by Riverbed in or pursuant to
this Agreement or in any document delivered pursuant hereto shall be deemed to
have been made on the date of this Agreement (except as otherwise provided
herein) and, if a Closing occurs, as of the Closing Date and Effective Time,
subject to the provisions of Section 8.3. The representations and warranties of
Aether and Riverbed will survive the Closing and will remain in effect until,
and will expire upon, the first anniversary of the Closing Date and the
covenants of Aether and Riverbed will survive the Closing and will remain in
effect in accordance with the terms therein.

      Section 9.8 Severability. Any provision or part of this Agreement which
is invalid or unenforceable in any situation in any jurisdiction shall, as to
such situation and such jurisdiction, be ineffective only to the extent of such
invalidity and shall not affect the enforceability of the remaining provisions
hereof or the validity or enforceability of any such provision in any other
situation or in any other jurisdiction.

      Section 9.9 Successors and Assigns; Third Parties. Subject to and without
waiver of the provisions of Section 9.6, all of the rights, duties, benefits,
liabilities and obligations of the parties shall inure to the benefit of, and
be binding upon, their respective successors, assigns, heirs and legal
representatives. Except as specifically set forth in Section 3.2, Section 3.3,
Section 3.5, Section 3.6, Section 6.15, Section 6.16, Section 6.17, Section
6.19, Section 6.20, and Section 6.21 nothing herein expressed or implied is
intended or shall be construed to confer upon or give to any person or entity,
other than the parties hereto and their successors or permitted assigns, any
rights or remedies under or by reason of this Agreement.

      Section 9.10 Counterparts. This Agreement may be executed in as many
counterparts as may be deemed necessary and convenient, and by the different
parties hereto on separate counterparts each of which, when so executed, shall
be deemed an original, but all such counterparts shall constitute one and the
same instrument.

      Section 9.11 Interpretation; References. Any use of masculine, feminine
or neuter pronouns herein shall not be limiting, but shall be construed as
referring to persons of any gender, as the context may require. Any use of the
singular or plural form herein shall not be limiting, but shall be construed as
referring to either the plural or singular, as the context may require.
References to a "Schedule" or an "Exhibit" are, unless otherwise specified, to
a Schedule attached to the Disclosure Letter or an Exhibit attached to this
Agreement, and references to an "Article" or a "Section" are, unless otherwise
specified, to an Article or a Section of this Agreement. The Article and
Section headings of this Agreement are for convenience of reference only and
shall not be deemed to modify, explain, restrict, alter or affect the meaning
or interpretation of any provision hereof.



                                                                        58

<PAGE>   64


      Section 9.12 Dispute Resolution and Jurisdiction.

      (a) Each party to this Agreement shall appoint a Representative to
coordinate with the other party the implementation of this Agreement. If any
dispute arises with respect to either party's performance hereunder, the
Representatives shall meet to attempt to resolve such dispute, either in person
or by telephone, within two (2) Business Days after the written request of
either Representative. If the Representatives are unable to resolve such
dispute, the chief executive officer of Riverbed and the chief financial
officer of Aether shall meet, either in person or by telephone, within ten (10)
Business Days after either Representative provides written notice that the
Representatives have been unable to resolve such dispute. If such officers are
unable to resolve such dispute, either party may submit such dispute to an
independent nationally-recognized accounting firm, if such dispute is solely of
a financial nature.

      Section 9.13 Exhibits, Schedules and Disclosure Letter. All exhibits and
schedules attached hereto and the Disclosure Letter are hereby incorporated by
reference as though set out in full herein.

      Section 9.14 Attorneys' Fees. In the event that any party hereto brings
an action or proceeding against the other party to enforce or interpret any of
the covenants, conditions, agreements or provisions of this Agreement, the
prevailing party in such action or proceeding shall be entitled to recover all
costs and expenses of such action or proceeding, including, without limitation,
reasonable attorneys' fees, charges, disbursements and the fees and costs of
expert witnesses.

      Section 9.15 WAIVER OF JURY TRIAL. EACH PARTY TO THIS AGREEMENT WAIVES
ITS RESPECTIVE RIGHT TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION ARISING
OUT OF THIS AGREEMENT OR ANY DEALINGS BETWEEN ANY OF THE PARTIES HERETO
RELATING TO THE SUBJECT MATTER OF THIS AGREEMENT. THE SCOPE OF THIS WAIVER IS
INTENDED TO BE ALL-ENCOMPASSING OF ANY AND ALL DISPUTES THAT MAY BE FILED IN
ANY COURT AND THAT RELATE TO THE SUBJECT MATTER OF THIS AGREEMENT, INCLUDING,
WITHOUT LIMITATION, CONTRACT CLAIMS, TORT CLAIMS AND ALL OTHER COMMON LAW AND
STATUTORY CLAIMS. THIS WAIVER IS IRREVOCABLE, MEANING THAT IT MAY NOT BE
MODIFIED EITHER ORALLY OR IN WRITING, AND THIS WAIVER SHALL APPLY TO ANY
SUBSEQUENT AMENDMENTS, SUPPLEMENTS OR MODIFICATIONS TO THIS AGREEMENT OR TO ANY
OTHER DOCUMENT OR AGREEMENT RELATING TO THE TRANSACTIONS.

      Section 9.16 Further Assurances. Each of the parties shall, without
further consideration, use reasonable efforts to execute and deliver such
additional documents and take such other action as the other parties, or any of
them, may reasonably request to carry out the intent of this Agreement and the
Transactions.

      Section 9.17 Negotiation of Agreement. Each of the parties acknowledges
that it has been represented by independent counsel of its choice throughout
all negotiations that have preceded the execution of this Agreement and that it
has executed the same with consent and



                                                                        59

<PAGE>   65


upon the advice of said independent counsel. Each party and its counsel
cooperated in the drafting and preparation of this Agreement and the documents
referred to herein, and any and all drafts relating thereto shall be deemed the
work product of the parties and may not be construed against any party by
reason of its preparation. Accordingly, any rule of law or any legal decision
that would require interpretation of any ambiguities in this Agreement against
the party that drafted it is of no application and is hereby expressly waived.
The provisions of this Agreement shall be interpreted in a reasonable manner to
effect the intentions of the parties and this Agreement.

                            (signature page follows)



                                                                        60


<PAGE>   66


IN WITNESS WHEREOF, the parties hereto have caused this Agreement and Plan of
Merger to be duly executed and delivered as of the date first above written.

                                  AETHER SYSTEMS, INC.



                                  By:
                                         ---------------------------------
                                         Name:
                                         Title:



                                  RT ACQUISITION, INC.



                                  By:
                                         ---------------------------------
                                         Name:
                                         Title:



                                  RIVERBED TECHNOLOGIES, INC.



                                  By:
                                         ---------------------------------
                                         Name:
                                         Title:


                                                                     61


<PAGE>   1
                                                                   Exhibit 10.23



                  SERIES B PREFERRED STOCK PURCHASE AGREEMENT



                                January 18, 2000
<PAGE>   2




                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                PAGE
                                                                                ----
<S>       <C>                                                                   <C>
SECTION 1 Authorization and Sale of the Series B Preferred........................4
          ------------------------------------------------

            1.1         Authorization of the Series B Preferred...................4
                        ---------------------------------------
            1.2         Sale of the Series B Preferred............................4
                        ------------------------------

SECTION 2 Closing Date; Delivery..................................................5
          ----------------------

            2.1         Closing Date..............................................5
                        ------------
            2.2         Delivery..................................................5
                        --------
            2.3         Subsequent Sale of Series B Preferred.....................5
                        -------------------------------------

SECTION 3 Representations and Warranties of the Company...........................5
          ---------------------------------------------

            3.1         Organization and Standing.................................6
                        -------------------------
            3.2         Capitalization............................................6
                        --------------
            3.3         Subsidiaries, Etc.........................................6
                        -----------------
            3.4         Stockholder List and Agreements...........................7
                        -------------------------------
            3.5         Issuance of Shares........................................7
                        ------------------
            3.6         Authorization.............................................7
                        -------------
            3.7         Governmental Consents.....................................8
                        ---------------------
            3.8         Litigation................................................8
                        ----------
            3.9         Financial Statements......................................8
                        --------------------
            3.10        Title to Property and Assets and Liabilities..............8
                        --------------------------------------------
            3.11        Intellectual Property.....................................8
                        ---------------------
            3.12        Material Contracts and Obligations........................9
                        ----------------------------------
            3.13        Permits; Compliance.......................................9
                        -------------------
            3.14        Employees................................................10
                        ---------
            3.15        Proprietary Information and Inventions Agreements........10
                        -------------------------------------------------
            3.16        Environmental Matters....................................10
                        ---------------------
            3.17        ERISA....................................................11
                        -----
            3.18        Transactions with Related Parties........................11
                        ---------------------------------
            3.19        Books and Records........................................11
                        -----------------
            3.20        Year 2000................................................12
                        ---------
            3.21        Real Property Holding Company............................12
                        -----------------------------
            3.22        Disclosures..............................................12
                        -----------
            3.23        Additional Share Issuances...............................12
                        --------------------------
            3.24        Private Placement........................................12
                        -----------------
            3.25        Tax Returns, Payments and Elections......................12
                        -----------------------------------
            3.26        Investment Company Act...................................12
                        ----------------------

SECTION 4 Representations and Warranties of the Purchasers.......................13
          ------------------------------------------------

            4.1         Investment Representations of the Purchasers.............13
                        --------------------------------------------
            4.2         Authorization............................................14
                        -------------
            4.3         Legends..................................................14
                        -------
</TABLE>

                                      -i-
<PAGE>   3

<TABLE>
<S>         <C>                                                                  <C>
            4.4         Investor Counsel.........................................14
                        ----------------
            4.5         No Intent to Dispose.....................................14
                        --------------------

SECTION 5 Conditions to Closing of the Purchasers................................15
          ---------------------------------------

            5.1         Representations and Warranties Correct...................15
                        --------------------------------------
            5.2         Performance..............................................15
                        -----------
            5.3         Opinion of Company's Counsel.............................15
                        ----------------------------
            5.4         Rights Agreement.........................................15
                        ----------------
            5.5         ROFR Agreement...........................................15
                        --------------
            5.6         Voting Agreement.........................................15
                        ----------------
            5.7         Board of Directors.......................................15
                        ------------------
            5.8         Restated Certificate.....................................15
                        --------------------
            5.9         Compliance Certificate...................................16
                        ----------------------
            5.10        Other Matters............................................16
                        -------------

SECTION 6 Conditions to Closing of the Company...................................16
          ------------------------------------

            6.1         Representations..........................................16
                        ---------------
            6.2         Payment of Purchase Price................................16
                        -------------------------
            6.3         Other Matters............................................16
                        -------------

SECTION 7 Covenants of the Company...............................................16
          ------------------------

            7.1         Insurance................................................16
                        ---------

SECTION 8 Miscellaneous..........................................................17
          -------------

            8.1         Governing Law............................................17
                        -------------
            8.2         Survival.................................................17
                        --------
            8.3         Rights of Purchasers.....................................17
                        --------------------
            8.4         Successors and Assigns...................................17
                        ----------------------
            8.5         Entire Agreement; Amendment..............................17
                        ---------------------------
            8.6         Notices, etc.............................................17
                        ------------
            8.7         Delays or Omissions......................................18
                        -------------------
            8.8         Headings.................................................18
                        --------
            8.9         Severability.............................................18
                        ------------
            8.10        Finders Fee..............................................18
                        -----------
            8.11        Further Assurances.......................................18
                        ------------------
            8.12        Titles and Subtitles.....................................18
                        --------------------
            8.13        Counterparts.............................................18
                        ------------
            8.14        Additional Parties.......................................18
                        ------------------
            8.15        Expenses.................................................19
                        --------
</TABLE>


                                      -ii-
<PAGE>   4






<TABLE>
<CAPTION>

SCHEDULES AND EXHIBITS

<S>        <C>
Schedule A  Schedule of Purchasers
Schedule B  Schedule of Exceptions
Exhibit A   Second Amended and Restated Certificate of Incorporation
Exhibit B   Amended and Restated Investors' Rights Agreement
Exhibit C   Amended and Restated Right of First Refusal and Co-Sale Agreement
Exhibit D   Amended and Restated Voting Agreement
Exhibit E   Opinion of Wilson Sonsini Goodrich & Rosati
</TABLE>


                                      -iii-
<PAGE>   5







                               OMNISKY CORPORATION

                   SERIES B PREFERRED STOCK PURCHASE AGREEMENT

            This Agreement is made as of January 18, 2000, by and among OmniSky
Corporation (formerly known as "AirWeb Corporation"), a Delaware corporation
(the "COMPANY"), and each of the purchasers listed on the Schedule of Purchasers
attached hereto as Schedule A (the "SCHEDULE OF PURCHASERS"). The persons or
entities listed thereon are hereinafter referred to collectively as the
"PURCHASERS" and individually as a "PURCHASER."

                              W I T N E S S E T H:

            WHEREAS, the Company desires to issue and sell, and the Purchasers
desire to purchase, in exchange for cash and/or the contribution of assets, up
to 4,319,654 shares of the Company's Series B Preferred Stock, par value $.001
per share (the "SERIES B PREFERRED"), upon the terms and conditions hereinafter
set forth.

            NOW THEREFORE, in consideration of the foregoing and the mutual
covenants, agreements and warranties herein contained, the parties hereto agree
as follows:

                                   SECTION 1

                Authorization and Sale of the Series B Preferred

            1.1    Authorization of the Series B Preferred. The Company has, or
before the Closing (as hereinafter defined) will have, authorized the sale and
issuance of up to 5,000,000 shares of its Series B Preferred, having the rights,
restrictions, privileges and preferences as set forth in the Company's Amended
and Restated Certificate of Incorporation attached hereto as Exhibit A (the
"RESTATED CERTIFICATE").


            1.2    Sale of the Series B Preferred. Subject to the terms and
conditions hereof and in reliance upon the representations, warranties and
agreements contained herein, the Company will issue and sell to each Purchaser,
severally and not jointly, and each Purchaser, severally and not jointly, will
purchase from the Company, at the Closing, the number of shares of Series B
Preferred set forth opposite the Purchaser's name on the Schedule of Purchasers,
at a purchase price of $4.63 per share. The Company's agreement with each
Purchaser is a separate agreement, and the sale of the Series B Preferred to
each Purchaser is a separate sale.


<PAGE>   6


                                    SECTION 2

                             Closing Date; Delivery

            2.1    Closing Date. The closing of the purchase and sale of the
Series B Preferred hereunder (the "CLOSING") shall be held at the offices of
Wilson Sonsini Goodrich & Rosati, Professional Corporation, 650 Page Mill Road,
Palo Alto, California 94304 at 10:00 a.m. on January 18, 2000 (the "CLOSING
DATE") or at such other time and place as shall be mutually agreed upon by the
Company and the Purchasers who have subscribed for at least a majority of the
Series B Preferred to be sold at the Closing.


            2.2    Delivery. At the Closing, the Company shall deliver to each
Purchaser a certificate, in such denomination and registered in the Purchaser's
name as set forth on the Schedule of Purchasers, representing the number of
shares of Series B Preferred which such Purchaser is purchasing from the Company
against delivery to the Company of a check or wire transfer payable to the order
of the Company in the aggregate amount of the purchase price of the Series B
Preferred to be purchased by such Purchaser.


            2.3    Subsequent Sale of Series B Preferred. If less than all of
the authorized number of shares of Series B Preferred are sold on the Closing
Date, then, subject to the terms and conditions of this Agreement and the
Related Agreements (as defined below), the Company may sell, on or before March
18, 2000, up to the balance of the authorized but unissued shares of the Series
B Preferred to such persons as the Board of Directors of the Company (the
"BOARD") may determine at the same price per share as the Series B Preferred
purchased and sold at the Closing (the date of any such sale also being referred
to herein as a "CLOSING DATE"). Any such sale shall be made upon the same terms
and conditions as those contained herein, and such persons or entities shall
become parties to this Agreement, the Amended and Restated Investors' Rights
Agreement attached hereto as Exhibit B (the "RIGHTS AGREEMENT"), the Amended and
Restated Right of First Refusal and Co-Sale Agreement attached hereto as Exhibit
C (the "ROFR AGREEMENT"), the Amended and Restated Voting Agreement attached
hereto as Exhibit D (the "VOTING AGREEMENT"), and any other agreement to which
the other Purchasers are party and the execution and delivery of which is
contemplated hereby (collectively, the "RELATED AGREEMENTS"), and shall have the
rights and obligations of a Purchaser hereunder and thereunder. Such persons or
entities shall also execute and deliver such documents and certificates as are
reasonably required to comply with applicable state, federal and foreign
securities laws.

                                    SECTION 3

                  Representations and Warranties of the Company

            The Company represents and warrants to each of the Purchasers that
the statements made in this Section 3 are true and correct, except as set forth
in the Schedule of Exceptions attached hereto as Schedule B (the "SCHEDULE OF
EXCEPTIONS"), which shall be arranged to correspond to the numbered paragraphs
contained in this Section 3. Without limiting the generality of the foregoing,



                                      -5-
<PAGE>   7



the mere listing (or inclusion of a copy) of a document or other item shall not
be deemed adequate to disclose an exception to a representation or warranty made
herein (unless the representation or warranty relates to the existence of the
document or other item itself).


            3.1    Organization and Standing. The Company is a corporation duly
organized, validly existing and in good standing under the laws of the State of
Delaware and has full corporate power and authority to conduct its business as
presently conducted and as proposed to be conducted by it and to enter into and
perform this Agreement and the Related Agreements to which the Company is a
party and to carry out the transactions contemplated by this Agreement and such
Related Agreements. The Company is duly qualified and in good standing to do
business in each jurisdiction (whether domestic or foreign) where the failure to
be so qualified would have a material adverse effect on the Company. The Company
has furnished to counsel for the Purchasers true and complete copies of its
Certificate of Incorporation and Bylaws, each as amended to date and currently
in effect.


            3.2    Capitalization. The authorized capital stock of the Company
consists of 40,000,000 shares of Common Stock, $0.001 par value, of which
4,200,000 shares are issued and outstanding and of which 5,800,000 shares have
been reserved for issuance pursuant to the OmniSky Corporation 1999 Stock Plan
(the "1999 STOCK PLAN"), and 30,000,000 shares of Preferred Stock, $0.001 par
value, of which 25,000,000 shares are designated as Series A Preferred Stock
("SERIES A PREFERRED") and of which 5,000,000 shares are designated as Series B
Preferred, of which 20,219,335 shares of Series A Preferred and no shares of
Series B Preferred shall be issued and outstanding prior to the date hereof. The
Company has reserved 20,219,335 shares of Common Stock for issuance upon
conversion of the Series A Preferred and 4,319,427 shares of Common Stock for
issuance upon conversion of the Series B Preferred. All of the issued and
outstanding shares of Common Stock have been duly authorized and validly issued
and are fully paid and nonassessable. The rights, privileges and preferences of
the Series A Preferred and Series B Preferred are as stated in the Restated
Certificate. Except as provided in this Agreement, the Restated Certificate, any
Related Agreement and pursuant to the 1999 Stock Plan: (a) no subscription,
warrant, option, convertible security or other right (contingent or otherwise)
to purchase or acquire any shares of capital stock of the Company is authorized
or outstanding; (b) the Company has no obligation (contingent or otherwise) to
issue any subscription, warranty option, convertible security or other such
right or to issue or distribute to holders of any shares of its capital stock
any evidences of indebtedness or assets of the Company; and (c) the Company has
no obligation (contingent or otherwise) to purchase, redeem or otherwise acquire
any shares of its capital stock or any interest therein or to pay any dividend
or make any other distribution in respect thereof. All of the issued and
outstanding shares of capital stock of the Company have been offered, issued and
sold by the Company in compliance with applicable federal and state securities
laws or pursuant to valid exemptions therefrom, and, if issued to a non-US
person, in full observance and compliance with the securities laws of such
holder's jurisdiction.


            3.3    Subsidiaries, Etc. The Company has no subsidiaries and does
not own or control, directly or indirectly, any shares of capital stock of any
other corporation or any interest in any partnership, joint venture, limited
liability company, professional association or other business enterprise.


                                      -6-
<PAGE>   8

            3.4    Stockholder List and Agreements. The Schedule of Exceptions
contains a true and complete list of the stockholders of the Company, showing
the number of shares of Common Stock or other securities of the Company held by
each stockholder as of the date of this Agreement and the date of the Closing
and the consideration paid to the Company, if any, therefor. Except as provided
in this Agreement, the Restated Certificate, any Related Agreement and pursuant
to the 1999 Stock Plan, there are no agreements, written or oral, between the
Company and any holder of its capital stock or, to the best of the Company's
knowledge, among any holders of its capital stock relating to the acquisition
(including without limitation rights of first refusal or preemptive rights),
transfer, sale or other disposition, registration under the Securities Act of
1933, as amended (the "SECURITIES ACT") or voting of the capital stock of the
Company.



            3.5    Issuance of Shares. Prior to the initial Closing, the
issuance, sale and delivery of the shares of Series B Preferred in accordance
with this Agreement, and the issuance and delivery of the shares of Common Stock
issuable upon conversion of the shares of Series B Preferred, will be duly
authorized by all necessary corporate action on the part of the Company and its
officers, directors and stockholders, and all such shares have been duly
reserved for issuance. The shares of Series B Preferred, when so issued, sold
and delivered against payment therefor in accordance with the provisions of this
Agreement, and the shares of Common Stock issuable upon conversion of the shares
of Series B Preferred, when issued upon such conversion in accordance with the
Restated Certificate, will be duly and validly issued, fully paid and
non-assessable. The offer and sale of the shares of Series B Preferred (and
Common Stock issued upon conversion thereof) to each of the Purchasers will be
in full compliance with applicable federal and state securities laws.



            3.6    Authorization. The execution, delivery and performance by
the Company of this Agreement and all Related Agreements to which it is a party
and the consummation by the Company of the transactions contemplated hereby and
thereby, have been duly authorized by all necessary corporate action. All
corporate action on the part of the Company and its officers, directors and
stockholders necessary for the authorization, execution and delivery of this
Agreement and all Related Agreements, and the performance of all obligations of
the Company hereunder and thereunder has been taken or will be taken prior to
the initial Closing. This Agreement and each of the Related Agreements have been
duly executed and delivered by the Company and constitute valid and legally
binding obligations of the Company enforceable in accordance with their
respective terms, except (i) as limited by applicable bankruptcy, insolvency,
reorganization, moratorium or other laws of general application affecting
enforcement of creditors' rights generally, (ii) as limited by laws relating to
the availability of specific performance, injunctive relief or other equitable
remedies and (iii) to the extent indemnification provisions contained herein or
in any Related Agreement may be limited by applicable federal or state
securities laws. The execution, delivery and performance of the transactions
contemplated by this Agreement and the Related Agreements and compliance with
their provisions by the Company will not violate any provision of law and will
not conflict with or result in any breach of any of the terms, conditions or
provisions of, or constitute a default under, or require a consent or waiver
under, the Restated Certificate or Bylaws (each as amended to date) or any
indenture, lease, agreement or other instrument to which the Company is a party
or by which it or any of its properties is bound, or any decree, judgment,
order, statute, rule or regulation applicable to the Company, including without
limitation, Section 2115 of the California Corporations Code, as applicable.


                                      -7-
<PAGE>   9



            3.7    Governmental Consents. No consent, approval, order or
authorization of, or registration, qualification, designation, declaration or
filing with, any governmental authority is required on the part of the Company
in connection with the execution and delivery of this Agreement or the Related
Agreements, the offer, issuance, sale and delivery of the shares of Series B
Preferred or the other transactions to be consummated at the Closing, as
contemplated by this Agreement, except such filings as shall have been made
prior to and shall be effective on and as of such Closing.


            3.8    Litigation. There is no action, suit or proceeding or
governmental inquiry or investigation pending against the Company that questions
the validity of this Agreement or any Related Agreement or the right of the
Company to enter into or perform this Agreement or any Related Agreement, or
that could be expected to have, either individually or in the aggregate, any
material adverse effect on the business, prospects, assets or condition,
financial or otherwise, of the Company, nor is there any litigation pending
against the Company by reason of the proposed activities of the Company or
negotiations by the Company with possible investors in the Company.


            3.9    Financial Statements. The Company has delivered to the
Purchasers its unaudited financial statements (balance sheet and statement of
operations) as of December 31, 1999 and for the eight month period ended
December 31, 1999 (the "FINANCIAL STATEMENTS"). The Financial Statements have
been prepared in accordance with generally accepted accounting principles
applied on a consistent basis throughout the periods indicated and with each
other, except that such Financial Statements may not contain all footnotes
required by generally accepted accounting principles. The Financial Statements
fairly present the financial condition and operating results of the Company as
of the dates, and for the periods, indicated therein, subject to normal year-end
audit adjustments. Except as set forth in the Financial Statements, the Company
has no material liabilities, contingent or otherwise, other than (i) liabilities
occurred in the ordinary course of business subsequent to December 31, 1999 and
(ii) obligations under contracts and commitments incurred in the ordinary course
of business and not required under generally accepted accounting principles to
be reflected in the Financial Statements, which, in both cases, individually or
in the aggregate are not material to the financial condition or operating
results of the Company. Except as disclosed in the Financial Statements, the
Company is not a guarantor or indemnitor of any indebtedness of any other
person, firm or corporation.



            3.10   Title to Property and Assets and Liabilities. The Company
has good and marketable title to its material properties and assets, and has
good title to all its leasehold interests, in each case subject to no mortgage,
pledge, lien, lease, security interest, conditional sale agreement, encumbrances
or charge. The Company has not granted any manufacturing rights to any third
party. The Company is not in material violation of any zoning, building or
safety ordinance, regulation or requirement or other law or regulation
applicable to the operation of owned or leased properties likely to impede the
normal operation of the business of the Company, and the Company has not
received any written notice of violation with which it has not complied.

            3.11   Intellectual Property. The Company possesses legal rights to
all patents, trademarks, service marks, patent and trademark applications, trade
names, copyrights, mask-works, trade secrets, licenses, information and
proprietary rights, processes, data and know-how necessary for the conduct of
the Company's business as conducted and as proposed to be conducted (the
"INTELLECTUAL


                                      -8-
<PAGE>   10


PROPERTY RIGHTS"), free and clear of all Liens (as defined below), licenses or
other restrictions. The Schedule of Exceptions contains a complete list of the
Intellectual Property Rights. To the Company's knowledge, the business conducted
or proposed to be conducted by the Company does not cause the Company to
infringe or violate any of the patents, trademarks, service marks, trade names,
copyrights, mask-works, trade secrets, processes, data or know-how or other
intellectual property rights of any other individual, partnership, corporation,
association, joint stock company, trust, joint venture, limited liability
company, unincorporated organization or governmental entity or any department,
agency or political subdivision thereof (each being a "PERSON") and, to the
Company's knowledge, does not require the Company to obtain any license or other
agreement to use any patents, trademarks, service marks, trade names,
copyrights, trade secrets, processes, data or know-how of others. The Company
has not received any communications alleging that the Company has violated or,
by conducting its business as proposed to be conducted, would violate any of the
patents, trademarks, service marks, trade names, copyrights, mask-works, trade
secrets, processes, data and know-how of any other Person. There are no
outstanding options, licenses or agreements of any kind relating to the
Intellectual Property Rights, nor is the Company a party to any options,
licenses or agreements of any kind with respect to the patents, trademarks,
service marks, trade names, copyrights, mask-works, trade secrets, processes,
data or know-how of any other Person. None of the holders of Common Stock,
whether vested or unvested, owns any rights in patents, trademarks, service
marks, trade names, copyrights, mask-works, trade secrets, processes, data or
know-how directly or indirectly competitive with those owned or to be used by
the Company or derived from or in connection with the conduct of the Company's
business. The Company does not believe that it is or will be necessary to use
any inventions or works of authorship of its employees (or Persons it currently
intends to hire) made outside of their employment by the Company. For purposes
of this Agreement, "Liens" shall mean any lien, security interest, pledge,
mortgage, deed of trust, charge or encumbrance in real, personal or mixed
property (tangible or intangible, and wherever located), whether contractual or
statutory (each being a "LIEN"), of any nature other than those the material
terms of which are described in the Schedule of Exceptions or those which do not
materially impair the operations of the Company.


            3.12   Material Contracts and Obligations. The Schedule of
Exceptions sets forth a list of all material agreements or commitments of any
nature to which the Company is a party or by which it is or will be bound as of
the Closing Date, including without limitation: (i) each agreement that requires
future expenditures by the Company in excess of $25,000 or that might result in
payments to the Company in excess of $25,000; (ii) all management, consulting
and similar agreements; (iii) all employment and consulting agreements, employee
benefit, bonus, pension, profit-sharing, stock option, stock purchase and
similar plans and arrangements and distributor and sales representative
agreements; (iv) each agreement with any stockholder, officer or director of the
Company, or any affiliate of such Persons, including without limitation any
agreement or other arrangement providing for the furnishing of services by,
rental of real or personal property from, or otherwise requiring payments to,
any such Person or entity; and (v) any agreement relating to the Intellectual
Property Rights. The Company has delivered to the Purchasers copies of such of
the foregoing agreements as the Purchasers have requested. All of such
agreements and contracts are valid, binding and in full force and effect.


            3.13   Permits; Compliance. The Company holds all permits, orders
and approvals from governmental authorities required for the conduct of its
business as conducted or as proposed to be

                                      -9-
<PAGE>   11

conducted, or can obtain within a commercially reasonable period of time such
permits, orders and approvals without having a material adverse effect on such
business. There is no term or provision of any mortgage, indenture, material
contract, material agreement or material instrument to which the Company is a
party or by which it is bound or of any provision of any existing judgment,
decree, order, statute, rule or regulation applicable to or binding upon the
Company, that materially adversely affects or, so far as the Company may now
reasonably foresee, in the future is reasonably likely to materially adversely
affect, the business, prospects, assets or condition, financial or otherwise, of
the Company.


            3.14   Employees. None of the employees of the Company is
represented by any labor union, and, to the Company's knowledge, there is no
labor strike or other labor trouble pending with respect to the Company
(including, without limitation, any organizational drive) or threatened. No
employee of the Company is in violation of any judgment, decree, order, or any
term of any employment contract, patent disclosure agreement, or other contract
or agreement relating to the relationship of any such employee with the Company
or any other party because of the nature of the business conducted or presently
proposed to be conducted by the Company or to the use by the employee of his or
her best efforts with respect to such business. The employment of each officer
and employee is terminable at the will of the Company.



            3.15   Proprietary Information and Inventions Agreements. Each
employee and officer of the Company has executed the Company's standard
Proprietary Information and Inventions Agreement, a copy of which has been made
available to counsel for the Purchasers.

            3.16   Environmental Matters. With respect to environmental matters:

                   The Company is and has been in compliance with all
Environmental Laws (as defined below), and no action, suit, proceeding, hearing,
investigation, charge, complaint, claim, demand or notice has been made, given,
filed or commenced by any Person, nor to the Company's knowledge has any such
making, giving, filing or commencement been threatened, against any of them
alleging any failure to comply with the Environmental Laws, or seeking
contribution towards, or participation in, any remediation of any contamination
of any property or thing with Hazardous Materials (as defined below). Without
limiting the generality of the preceding sentence, the Company has obtained and
been, and currently is, in compliance with all of the terms and conditions of
all permits, licenses and other authorizations that are required under, and has
complied with all other limitations, restrictions, conditions, standards,
prohibitions, requirements, obligations, schedules and timetables that are
contained in, all Environmental Laws;

                   The Company has no obligation to remediate or any other
liabilities of any kind arising in connection with or under any of the
Environmental Laws, nor is there any basis for such obligation or liabilities;

                   Except as set forth in the Schedule of Exceptions. all
properties and equipment used in the business of the Company are and have been
free of Hazardous Materials;

                   "Environmental Laws" means all federal, state and local laws,
regulations, ordinances, codes, rules, permits, decisions, orders or decrees
relating or pertaining to the public

                                      -10-
<PAGE>   12



health and safety or the environment, or otherwise governing the generation,
use, handling, collection, treatment, storage, transportation, recovery,
recycling, removal, discharge or disposal of Hazardous Materials, including,
without limitation, the Solid Waste Disposal Act, 42 U.S.C. 6901 et seq., as
amended (also known as "RCRA" for a subsequent amending act), (b) the
Comprehensive Environmental Response, Compensation and Liability Act, 42 U.S.C.
Section 9601 et seq., as amended ("CERCLA"), (c) the Clean Water Act, 33 U.S.C.
Section 1251 et seq., as amended ("CWA"), (d) the Clean Air Act, 42 U.S.C.
Section 7401 et seq., as amended ("CAA"), (e) the Toxic Substances Control Act,
15 U.S.C. Section 2601 et seq., as amended ("TSCA"), (f) the Emergency Planning
and Community Right To Know Act, 15 U.S.C. Section 2601 et seq., as amended
("EPCRKA"), and (g) the Occupational Safety and Health Act, 29 U.S.C. Section
651 et seq., as amended; and

                   Hazardous Materials means, without limitation, (i) any
"hazardous wastes" as defined under RCRA, (ii) any "hazardous substances" as
defined under CERCLA, (iii) any toxic pollutants as defined under the CWA, (iv)
any hazardous air pollutants as defined under the CAA, (v) any hazardous
chemicals as defined under TSCA, (vi) any hazardous substances as defined under
EPCRKA, (vii) asbestos, (viii) polychlorinated biphenyls, (ix) petroleum or
petroleum products, (x) underground storage tanks, whether empty, filled or
partially filled with any substance, (xi) any substance the presence of which on
the property in question is prohibited under any Environmental Law, and (xii)
any other substance which under any Environmental Law requires special handling
or notification of or reporting to any federal, state or local governmental
entity in its generation, use, handling, collection, treatment, storage,
recycling, treatment, transportation, recovery, removal, discharge or disposal.



            3.17   ERISA. The Company does not have or otherwise contribute to
or participate in any employee benefit plan subject to the Employee Retirement
Income Security Act of 1974 (other than the Company's 401(k) savings plan, 1999
Stock Plan and any medical benefit plan with respect to which the Company has
made all required contributions and has complied with all applicable laws).


            3.18   Transactions with Related Parties. Except as disclosed on
Schedule 3.18, no employee, officer, director or stockholder of the Company or
member of his or her immediate family is indebted to the Company, nor is the
Company indebted (or committed to make loans or extend or guarantee credit) to
any of them, other than (i) for payment of salary for services rendered, (ii)
reimbursement for reasonable expenses incurred on behalf of the Company and
(iii) for other employee benefits made generally available to all employees.
None of such persons has any direct or indirect ownership interest in any Person
with which the Company is affiliated or with which the Company has a business
relationship, or any Person that competes with the Company, except that
employees, stockholders, officers or directors of the Company and members of
their immediate families may own stock in publicly traded companies that may
compete with the Company. No officer, director or stockholder or any member of
their immediate families is, directly or indirectly, interested in any material
contract with the Company (other than such contracts as relate to any such
person's ownership of capital stock or other securities of the Company).


            3.19   Books and Records. The minute books of the Company contain
complete and accurate records of all meetings and other corporate actions of its
stockholders and its Board and committees thereof. The stock ledger of the
Company is complete and reflects all issuances, transfers, repurchases and
cancellations of shares of capital stock of the Company.

                                      -11-
<PAGE>   13


            3.20   Year 2000. As of the date hereof, to the knowledge of the
Company, Year 2000 computer malfunctions have not had and will not have a
material adverse effect on the condition (financial or otherwise), business,
operations, properties or prospects of the Company.


            3.21   Real Property Holding Company. The Company is not a real
property holding company within the meaning of Section 897 of the Code.


            3.22   Disclosures. Neither this Agreement, any Related Agreement
nor any exhibit hereto or thereto, nor any written report, certificate or
instrument furnished to any of the Purchasers in connection with the
transactions contemplated in this Agreement or the Related Agreements contains
any untrue statement of a material fact or, when taken together, omits to state
a material fact necessary in order to make the statements contained herein or
therein, in light of the circumstances under which they were made, not
misleading. However, as to any projections furnished to the Purchasers, the
Company only represents that such projections were prepared in good faith by the
Company and there is a reasonable basis for such projections. The Company knows
of no information or fact that has or would have a material adverse effect on
the business, prospects, assets or condition, financial or otherwise, of the
Company that has not been disclosed to the Purchasers in this Agreement, the
Related Agreements, the exhibits hereto or thereto or other written materials
furnished to the Purchasers.


            3.23   Additional Share Issuances. The Company is not under any
obligation or binding commitment to issue additional shares of its stock to any
person or entity.

            3.24   Private Placement. Subject in part to the truth and accuracy
of each Purchaser's representations set forth in this Agreement, the offer, sale
and issuance of the Series B Preferred as contemplated by this Agreement are
exempt from the registration requirements of the Securities Act, and neither the
Company nor any authorized agent acting on its behalf will take any action
hereafter that would cause the loss of such exemption.


            3.25   Tax Returns, Payments and Elections. The Company has filed
all tax returns and reports (federal, state and local) as required by law. These
returns and reports are true and correct in all material respects. The Company
has paid all taxes and other assessments due. The Company has not elected
pursuant to the Internal Revenue Code of 1986, as amended ("Code"), to be
treated as an S corporation pursuant to Section 1362(a). None of the Company's
federal income tax returns and none of its state income or franchise tax or
sales or use tax returns has ever been audited by governmental authorities. The
Company has made adequate provisions on its books of account for all taxes,
assessments, and governmental charges with respect to its business, properties,
and operations for the period from the date of incorporation to January 18,
2000. The Company has withheld or collected from each payment made to each of
its employees, the amount of all taxes, including, but not limited to, federal
income taxes, Federal Insurance Contribution Act taxes and Federal Unemployment
Tax Act taxes required to be withheld or collected therefrom, and has paid the
same to the proper tax receiving officers or authorized depositories.



            3.26   Investment Company Act. The Company is not an "investment
company" as defined in the Investment Company Act of 1940.

                                      -12-
<PAGE>   14

                                   SECTION 4

                Representations and Warranties of the Purchasers

            Each Purchaser, severally and not jointly, hereby represents and
warrants to the Company with respect to the purchase of the Series B Preferred
as follows:

            4.1    Investment Representations of the Purchasers. Purchaser
understands that the Series B Preferred (and the Common Stock issuable upon
conversion of the Series B Preferred) have not been registered under the
Securities Act and are being offered and sold pursuant to an exemption from
registration contained in the Act based upon the representations of each
Purchaser contained herein.

            Purchaser knows of no public solicitation or advertisement of an
offer in connection with the proposed issuance and sale of the Series B
Preferred.

            Purchaser is acquiring the Series B Preferred to be issued and sold
hereunder (and the Common Stock issuable upon conversion of the Series A
Preferred) for Purchaser's own account for investment and not as a nominee and
not with a view to the distribution thereof. Purchaser understands that
Purchaser must bear the economic risk of this investment indefinitely unless the
Series B Preferred or such Common Stock are registered pursuant to the Act, or
an exemption from such registration is available, and that the Company has no
present intention of registering the Series B Preferred or such Common Stock.
Purchaser further understands that there is no assurance that any exemption from
the Act will be available or, if available, that such exemption will allow
Purchaser to dispose of or otherwise transfer any or all of the Series B
Preferred or such Common Stock under the circumstances, in the amounts or at the
times Purchaser might propose.

            By reason of Purchaser's business or financial experience, or that
of Purchaser's professional advisor, Purchaser has the capacity to protect his
own interests in connection with the purchase of the Series B Preferred
hereunder and has the ability to bear the economic risk (including the risk of
total loss) of Purchaser's investment; provided, however, such capacity and/or
ability in no way serves to mitigate or release the Company from its obligations
or representations or warranties in this Agreement, the Related Agreements or
the Restated Certificate.

            Purchaser acknowledges that Purchaser is aware of Rule 144
promulgated under the Act, which permits limited public resales of securities
acquired in a non-public offering, subject to the satisfaction of certain
conditions. Purchaser understands that under Rule 144, except as otherwise
provided by section (k) of that Rule, the conditions include, among other
things: the availability of certain current public information about the issuer,
the resale occurring not less than one year after the party has purchased and
paid for the securities to be sold and limitations on the amount of securities
to be sold and the manner of sale. Purchaser understands that the current
information referred to above is not now available and the Company has no
present plans to make such information available. Purchaser acknowledges and
understands that notwithstanding the Company's obligations under the Rights
Agreement the Company may not be satisfying the current public information
requirement of Rule 144 at the time Purchaser wishes to sell the Series A


                                      -13-
<PAGE>   15


Preferred or any Common Stock received on conversion thereof, and that, in such
event, Purchaser may be precluded from selling such stock under such Rule, even
if the one year minimum holding period of such Rule has been satisfied.

            Purchaser acknowledges that in the event all of the requirements of
Rule 144 are not met, registration under the Act, compliance with the Securities
and Exchange Commission's (the "COMMISSION") Regulation A or an exemption from
registration will be required for any disposition of the Series B Preferred and
the Common Stock issued on conversion thereof. Purchaser understands that
although Rule 144 is not exclusive, the Commission has expressed its opinion
that persons proposing to sell restricted securities received in a private
offering other than in a registered offering or pursuant to Rule 144 will have a
substantial burden of proof in establishing that an exemption from registration
is available for such offers or sales and that such persons and the brokers who
participate in the transactions do so at their own risk.

            The residency of Purchaser (or, in the case of a partnership or
corporation, such entity's principal place of business as office) is correctly
set forth on the Schedule of Purchasers.

            4.2    Authorization. Purchaser has the full power and authority to
execute, deliver and perform this Agreement. This Agreement when executed and
delivered by Purchaser will constitute a valid and legally binding obligation of
Purchaser, enforceable in accordance with its terms, except (i) as limited by
applicable bankruptcy, insolvency, reorganization, moratorium or other laws of
general application affecting enforcement of creditors' rights generally, (ii)
as limited by laws relating to the availability of specific performance,
injunctive relief or other equitable remedies and (iii) to the extent
indemnification provisions contained herein or in any Related Agreement may be
limited by applicable federal or state securities laws.


            4.3    Legends. Purchaser understands and acknowledges that the
certificate evidencing such Purchaser's Series B Preferred and any Common Stock
acquired upon the conversion thereof will be imprinted with a legend in the form
set forth in Sections 3 and 20(d) of the Rights Agreement and in Section 4 of
the ROFR Agreement.


            4.4    Investor Counsel. Purchaser acknowledges that such Purchaser
has had the opportunity to review this Agreement, the exhibits and the schedules
attached hereto and the transactions contemplated by this Agreement with such
Purchaser's own legal counsel and has not relied upon the Company or any of its
agents for legal advice, other than the legal opinion provided pursuant to
Section 5.3 hereto, with respect to this investment or the transactions
contemplated by this Agreement.


            4.5    No Intent to Dispose. Purchaser has no current plan or
intention, and is not under any binding commitment or contract, to sell,
exchange or otherwise dispose of any stock in the Company, including without
limitation any Series B Preferred received or to be received pursuant to this
Agreement.

                                      -14-
<PAGE>   16


                                   SECTION 5

                     Conditions to Closing of the Purchasers

            The obligation of each of the Purchasers to purchase the Series B
Preferred at the Closing is subject to the fulfillment to the Purchaser's
satisfaction on or prior to the Closing Date of each of the following
conditions:



            5.1    Representations and Warranties Correct. Each representation
and warranty made by the Company in Section 3 hereof shall be true and correct
when made and on the Closing Date.


            5.2    Performance. All covenants, agreements and conditions
            contained in this Agreement to be performed or complied with by the
Company on or prior to the Closing Date shall have been performed or complied
with by the Company in all respects.


            5.3    Opinion of Company's Counsel. The Purchasers shall have
received from Wilson Sonsini Goodrich & Rosati, counsel to the Company, an
opinion addressed to the Purchasers, dated the Closing Date and in substantially
the form attached hereto as Exhibit E.


            5.4    Rights Agreement. The Company, each of the Purchasers and a
majority of the Registrable Securities (as defined in the Rights Amendment), and
each Founder (as defined in the Rights Agreement) shall have entered into and
delivered the Rights Agreement at or prior to the Closing, and the Rights
Agreement shall be in full force and effect, without amendment or modification.


            5.5    ROFR Agreement. The Company, each of the Purchasers and the
holders of Series A Preferred Stock, the holders of Series B Preferred Stock and
the Founders (as defined in the ROFR Agreement) shall have entered into and
delivered the ROFR Agreement, at or prior to the Closing, and the ROFR Agreement
shall be in full force and effect, without amendment or modification.


            5.6    Voting Agreement. Each of the Purchasers and the holders of
Series A Preferred Stock, the holders of Series B Preferred Stock and the
Founders (as defined in the Voting Agreement) shall have entered into and
delivered the Voting Agreement, at or prior to the Closing, and the Voting
Agreement shall be in full force and effect, without amendment or modification.


            5.7    Board of Directors. The Company's Bylaws shall provide for a
Board of Directors, with the number of directors fixed at seven (7). As of the
Closing, the following individuals shall be members of the Board of Directors of
the Company: (i) Janice Roberts, (ii) David Oros, (iii) Patrick McVeigh and (iv)
Stephen Diamond.


            5.8    Restated Certificate. The Restated Certificate shall have
been filed with the Secretary of State of the State of Delaware, shall have
become effective in accordance with Section 103 of the Delaware General
Corporation Law, as amended, and shall not have been further modified or
amended.

                                      -15-
<PAGE>   17


            5.9    Compliance Certificate. The Company shall have delivered to
the Purchasers or their special counsel a certificate signed by the President of
the Company, dated the Closing Date, certifying to the fulfillment of the
conditions specified in Sections 5.1, 5.2, 5.7 and 5.8 above.


            5.10   Other Matters. All material matters of a legal nature which
pertain to the transactions contemplated in this Agreement, the Related
Agreements and all documents and instruments incident to such transactions shall
be reasonably satisfactory in substance and form to the Purchaser and its
counsel, and the Purchaser and its counsel shall have received all such
counterpart originals or certified or other copies of such documents as they may
reasonably request.

                                    SECTION 6

                      Conditions to Closing of the Company

            The Company's obligation to sell the Series B Preferred at the
Closing is subject to the fulfillment to its satisfaction on or prior to the
Closing Date of each of the following conditions:


            6.1    Representations. The representations made by the Purchasers
pursuant to Section 4 hereof shall be true in all material respects at and as of
the Closing.

            6.2    Payment of Purchase Price. Each Purchaser shall have
delivered to the Company the purchase price for such Purchaser's Series B
Preferred, as set forth opposite such Purchaser's name on the Schedule of
Purchasers.


            6.3    Other Matters. All material matters of a legal nature which
pertain to the transactions contemplated in this Agreement, the Related
Agreements and all documents and instruments incident to such transactions shall
be reasonably satisfactory in substance and form to the Company and its counsel,
and the Company and its counsel shall have received all such counterpart
originals or certified or other copies of such documents as they may reasonably
request.

                                   SECTION 7

                            Covenants of the Company

            The Company hereby covenants and agrees with the Purchasers as
follows:

            7.1    Insurance. The Company shall obtain by March 18, 2000 and
maintain valid policies of insurance with respect to its properties and business
of the kinds and in the amounts, not less than is customarily obtained by
corporations engaged in the same business and similarly situated, including,
without limitation, workers compensation insurance and insurance against
casualty loss, public liability, libel, slander, defamation, advertising injury
and other risks.

                                      -16-
<PAGE>   18

                                    SECTION 8

                                  Miscellaneous

            8.1    Governing Law. This Agreement shall be governed by and
construed and enforced in accordance with the laws of the State of Delaware,
without regard to conflicts of laws.

            8.2    Survival. The representations, warranties, covenants and
agreements made herein shall survive (i) the execution and delivery of this
Agreement and (ii) the Closing.

            8.3    Rights of Purchasers. Each Purchaser shall have the absolute
right to exercise or refrain from exercising any right or rights that such
Purchaser may have by reason of this Agreement, the Related Agreements, the
Restated Certificate, the Bylaws or at law or in equity including, without
limitation, the right to consent to the waiver of any obligation of the Company
and to enter into any agreement with the Company for the purpose of modifying
this Agreement or the Related Agreements and such Purchaser shall not incur any
liability to any other Purchaser or holder of Series B Preferred (or Common
Stock issued upon conversion thereof) with respect to exercising or refraining
from exercising any such right or rights. Each Purchaser acknowledges that such
Purchaser is not relying upon any other Purchaser in making its investment
decision to invest in the Company.


            8.4    Successors and Assigns. Except as otherwise expressly
provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon, the successors, assigns, heirs, executors and administrators of
the parties hereto. Notwithstanding any other provision of this Agreement to the
contrary, the rights and obligations of this Agreement may be expressly
transferred to any affiliate of the Purchasers.


            8.5    Entire Agreement; Amendment. This Agreement (including all
exhibits hereto) and the other documents delivered pursuant hereto constitute
the full and entire understanding and agreement among the parties with regard to
the subjects hereof and thereof. This Agreement and any term hereof may be
amended, waived, discharged or terminated only by means of a written instrument
signed by the Company and Purchasers (or their respective successor or assigns)
holding at least a majority of the shares of Series B Preferred (or Common Stock
issued upon conversion thereof) then outstanding. Any amendment, waiver,
discharge or termination not in compliance with this Section 7.5 shall be void.


            8.6    Notices, etc. All notices and other communications required
or permitted hereunder shall be in writing and shall be mailed by first-class
mail, postage prepaid, or delivered either by hand, by messenger, by overnight
courier service or by confirmed facsimile, addressed (a) if to Purchaser, as
indicated on the Schedule of Purchasers, or at such other address as Purchaser
shall have furnished to the Company in writing, or (b) if to any other holder of
any Series B Preferred or any Common Stock issued upon conversion of Series B
Preferred, at such address as such holder shall have furnished the Company in
writing or, until any such holder so furnishes an address to the Company, then
to and at the address of the last holder thereof who has so furnished an address
to the Company, or (c) if to the Company, at its address set forth at the end of
this Agreement or at such



                                      -17-
<PAGE>   19


other address as the Company shall have furnished to the Purchasers and each
such other holder in writing.


            8.7    Delays or Omissions. No delay or omission to exercise any
right, power or remedy accruing to any holder of any Series B Preferred (or
Common Stock issued upon conversion thereof) upon any breach or default of the
Company under this Agreement shall impair any such right, power or remedy of
such holder, nor shall it be construed to be a waiver of any such breach or
default or an acquiescence therein, or of or in any similar breach or default
thereafter occurring; nor shall any waiver of any single breach or default be
deemed a waiver of any other breach or default theretofore or thereafter
occurring. Any waiver, permit, consent or approval of any kind or character on
the part of any holder of any breach or default under this Agreement, or any
waiver on the part of any holder of any provisions or conditions of this
Agreement, must be made in writing and shall be effective only to the extent
specifically set forth in such writing. All remedies, either under this
Agreement or by law or otherwise afforded to any holder, shall be cumulative and
not alternative.

            8.8    Headings. The headings of this Agreement are for convenience
only and should not be used to construe or interpret the terms of this
Agreement.

            8.9    Severability. In case any provision of the Agreement shall be
held to be invalid, illegal or unenforceable, such provision shall be excluded
from this Agreement the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby.



            8.10   Finders Fee. Each party represents that it neither is nor
will be obligated for any finders' fee or commission in connection with this
transaction. Each Purchaser agrees, severally and not jointly, to indemnify and
to hold harmless the Company from any liability for any commission or
compensation in the nature of a finders' fee (and the costs and expenses of
defending against such liability or asserted liability) for which such Purchaser
or any of its officers, partners, employees, or representatives is responsible.
The Company agrees to indemnify and hold harmless each Purchaser from any
liability for any commission or compensation in the nature of a finders' fee
(and the costs and expenses of defending against such liability or asserted
liability) for which the Company or any of its officers, employees,
representatives or predecessors-in-interests is responsible.


            8.11   Further Assurances. Each party to this Agreement hereby
covenants and agrees, without the necessity of any further consideration, to
execute and deliver any and all such further documents and take any and all such
other actions as may be necessary or appropriate to carry out the intent and
purposes of this Agreement and to consummate the transactions contemplated
herein.


            8.12   Titles and Subtitles. The titles of the paragraphs and
subparagraphs of this Agreement are for convenience of reference only and are
not to be considered in construing this Agreement.

            8.13   Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.

            8.14   Additional Parties. The parties hereto agree that additional
purchasers of Series B Preferred may, with the consent only of the Company and
as otherwise set forth in Section 2.3 of the

                                      -18-
<PAGE>   20



Agreement, be added as parties to this Agreement, and shall thereupon be deemed
for all purposes "Purchasers" hereunder. Any such additional party shall execute
a counterpart of this Agreement, and upon execution by such additional party and
by the Company, shall be considered a Purchaser for purposes of this Agreement.




            8.15   Expenses. Each of the Company and the Purchasers shall bear
their own expenses incurred with respect to this Agreement and the transactions
contemplated hereby; however, in the event the Closing is consummated, the
Company will pay the reasonable fees and expenses of counsel to the Lead
Purchaser, not to exceed $20,000, in connection with all transactions leading up
to and related to the Closings.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


                                      -19-
<PAGE>   21





            IN WITNESS WHEREOF, the undersigned have executed this Agreement as
of the date set forth above.

                                   COMPANY:

                                   OMNISKY CORPORATION

                                   By:
                                      -------------------------------
                                   Name:
                                        -----------------------------
                                   Title:
                                         ----------------------------
                                   Address:
                                           --------------------------

                                           --------------------------



          SIGNATURE PAGE TO SERIES B PREFERRED STOCK PURCHASE AGREEMENT


<PAGE>   22



                                      PURCHASERS:

                                      DLJ CAPITAL CORP.

                                      By:  Stephen M. Diamond
                                           Vice President

                                      By:
                                         ----------------------------
                                                 (Signature)

                                      Name:
                                           --------------------------
                                                 (Print Name)

                                      Title:
                                             ------------------------


                                      DLJ ESC II, L.P.

                                      By:  DLJ LBO Plans Management Corporation
                                           General Partner

                                      By:
                                        -----------------------------
                                                  (Signature)

                                      Name:
                                           --------------------------
                                                  (Print Name)

                                      Title:
                                             ------------------------



         SIGNATURE PAGE TO SERIES B PREFERRED STOCK PURCHASE AGREEMENT
<PAGE>   23


                              SPROUT CAPITAL VIII, L.P.

                              By:  DLJ Capital Corp.
                                   Managing General Partner

                              By:
                                 ---------------------------
                                         (Signature)

                              Name:
                                   -------------------------
                                         (Print Name)

                              Title:
                                    ------------------------


                              SPROUT VENTURE CAPITAL, L.P.

                              By:  DLJ Capital Corp.
                                   General Partner

                              By:
                                 ---------------------------
                                        (Signature)

                              Name:
                                   -------------------------
                                        (Print Name)

                              Title:
                                    ------------------------


         SIGNATURE PAGE TO SERIES B PREFERRED STOCK PURCHASE AGREEMENT
<PAGE>   24

                              AETHER OPENSKY INVESTMENTS LLC

                              By:  Aether Technologies International, L.L.C.
                                   Its Sole Member

                              By:
                                 ---------------------------
                                         (Signature)

                              Name:
                                   -------------------------
                                         (Print Name)

                              Title:
                                    -------------------------



         SIGNATURE PAGE TO SERIES B PREFERRED STOCK PURCHASE AGREEMENT


<PAGE>   25


                                          WS INVESTMENT COMPANY

                                          By:
                                             --------------------------
                                                    (Signature)

                                          Name:
                                                -----------------------
                                                    (Print Name)

                                          Title:
                                                -----------------------



         SIGNATURE PAGE TO SERIES B PREFERRED STOCK PURCHASE AGREEMENT
<PAGE>   26


                                          Name:

                                          By:
                                             ---------------------------
                                          Name:
                                               -------------------------
                                                      (Print Name)

               SIGNATURE PAGE TO SERIES B PREFERRED STOCK AGREEMENT



<PAGE>   1
                                                                   EXHIBIT 10.24

                                MASTER AGREEMENT

     This Master Agreement (together with all exhibits and attachments hereto
and as modified from time to time, this "Agreement") effective as of December
23, 1999 (the "EFFECTIVE DATE"), is entered into by and between Charles Schwab &
Co., Inc., a California corporation, with its principal place of business at 101
Montgomery Street, San Francisco, CA 94104 and its affiliates, successors and
assigns ("SCHWAB"), and Aether Systems, Inc., a Delaware corporation, with its
principal place of business at 11460 Conridge Avenue, Suite 106, Owings Mills,
MD 21117 ("AETHER").

                                    RECITALS

     A. Schwab is registered as a broker-dealer with the U.S. Securities and
Exchange Commission (the "SEC") and is a member of the New York Stock Exchange
(the "NYSE") and the National Association of Securities Dealers, Inc. (the
"NASD"). Schwab offers various financial services, including without limitation,
brokerage services. Schwab makes such financial services available to customers,
prospects and other users (collectively "SCHWAB USERS") through web sites,
desktops, email, wireless and other communications channels developed, owned,
licensed, operated, hosted or otherwise controlled by Schwab or any Schwab
affiliate ("SCHWAB SERVICES");

     B. Aether has developed a suite of technologies, competencies and services
for the enabling of wireless data communication access, including the
development or provision of any related software supporting multiple wireless
data networks, information appliance devices and server technologies ("WIRELESS
SYSTEMS");

     C. From time to time, Schwab may wish to make available to certain Schwab
Users certain Schwab Services through a wireless data access and transaction
system; and

     D. Aether is available to develop, integrate, test, deploy, license and/or
support such Wireless Systems for use by Schwab and certain Schwab Users.

     NOW, THEREFORE, in consideration of the mutual promises, conditions and
covenants set forth herein, and in return for good and valuable consideration,
the receipt and sufficiency of which is hereby specifically acknowledged, Schwab
and Aether hereby agree as follows:


                                       I.

                         DEVELOPMENT OF WIRELESS SYSTEMS

     1.1 WIRELESS PROJECTS. Schwab retains Aether, and Aether agrees, to perform
one or more projects involving the development, maintenance and/or support of
Wireless Systems (each, a "WIRELESS PROJECT"). Each Wireless Project will be
described in a written statement of work (a "WIRELESS PROJECT SCHEDULE" or "WP
SCHEDULE"), each of which will be

                                  Confidential
                                  Page l of 22
<PAGE>   2

effective when signed by Schwab and Aether. Each such WP Schedule will be
numbered and titled, and will set forth the respective responsibilities of
Schwab and Aether. Such WP Schedules will include, but will not be limited to,
each of the following items whenever such item is applicable to the Wireless
System covered by such WP Schedule:

     a. The effective date and term of the Wireless Project Schedule;

     b. The incorporation of this Agreement by reference;

     c. A description of the Wireless System, including specifications regarding
functionality, configuration, compatibility and integration;

     d. The teaming approach with resource estimates;

     e. Delivery and implementation schedules;

     f. Testing and acceptance criteria;

     g. Operational and maintenance specifications;

     h. Required service levels, including technical and user support;

     i. Licenses and ownership;

     j. Any marketing and promotional efforts; and

     k. Any additional or special terms and conditions.

     Subject to the terms and conditions of this Agreement, Aether will carry
out and complete the duties and responsibilities set forth in the applicable WP
Schedule. Aether agrees that the terms of this Agreement will apply to all
services performed by Aether even if a WP Schedule has not been completed for a
 particular Wireless Project.

     1.2 NOTICE OF DELAYS. Whenever there is an actual or potential delay to
Aether's performance under an applicable WP Schedule, Aether will immediately so
notify Schwab. Aether acknowledges that its delay may adversely affect Schwab's
business needs and hereby agrees to negotiate in good faith to arrive at an
equitable adjustment to the terms of this Agreement and/or the applicable WP
Schedule to compensate Schwab for any such delays.

     1.3 SCHWAB'S COOPERATION. Schwab acknowledges that Aether's ability to
perform will require Schwab to perform certain tasks, which will be
mutually agreed and set forth in the applicable WP Schedules. Schwab acknowledge
that its failure to perform such obligations may adversely affect Aether's
ability to meet its performance under this Agreement and hereby agrees to
negotiate in good faith to arrive at an equitable adjustment to the terms of
this Agreement and/or the applicable WP Schedule to compensate Aether for such
additional effort and costs.

                                  Confidential
                                  Page 2 of 21
<PAGE>   3

     1.4 SCHWAB REQUESTED MODIFICATIONS TO EXISTING WIRELESS SYSTEMS.
Schwab may request Aether to make modifications or enhancements to a Wireless
System already subject to this Agreement (an "EXISTING WIRELESS SYSTEM"). Each
such request will be described in a written statement of work describing such
modifications, enhancements or new development in appropriate detail (a "CHANGE
ORDER"). If the Change Order materially alters the original scope of the
applicable WP Schedule, the parties will negotiate in good faith to establish a
new WP Schedule.

          a. NON-MATERIAL MODIFICATIONS. If a Change Order does not require
Aether to incur any additional material costs or expenses, then Aether will
make such modifications within a commercially reasonable period in relation
to Schwab's stated business or legal requirements.

          b. MATERIAL MODIFICATIONS. If a Change Order does require Aether to
incur additional material costs or expenses, then, within ten (10) business
days of receiving the Change Order, Aether will provide Schwab with a
written, good-faith, non-binding assessment of such costs and expenses and
the time required to perform the modifications required by the Change
Order. Schwab will notify Aether in writing within ten (10) days after
receipt of any itemized statement from Aether as to whether Schwab wishes
Aether to implement such Change Order based on such statement. Schwab will
compensate Aether for implementation of such a Change Order in accordance
with the terms and conditions of the relevant Change Order and Aether's
statement, as provided prior to Aether's implementation of the Change
Order, if any.

     1.5 AETHER'S CHANGES AND UPGRADES. During the term of this Agreement and so
long as payments are current, Schwab will be entitled, without charge, to
all enhancements and changes to a Wireless System subject to this Agreement
developed and offered by Aether independently for such Wireless System when and
if made commercially available by Aether. In connection with such enhancements
or changes, the functionality or performance of a Wireless System may be
modified, including a conversion of its then existing software to a new version
with new and/or enhanced software features. In the event of such a conversion,
the parties agree that: (a) the new features will include at least the same
level of functionality that Schwab previously received from Aether; (b) Schwab's
payment obligations will remain unchanged during the then remaining term of this
Agreement notwithstanding such a change or modification; and (c) Schwab shall be
provided at least thirty (30) days in advance of any such changes, notice and a
demonstration of such changes. If Schwab reasonably perceives such advanced
demonstration to reveal a material adverse change to the performance of an
applicable Wireless System or type of services to be provided by Aether or a
material adverse effect on the compatibility with Schwab or the applicable end
users' hardware, software or browser configurations, then Schwab may, in its
sole and absolute discretion, reject such proposed changes or modifications, and
Aether will continue to maintain and support the then-existing version of the
applicable Wireless System for the remainder of this Agreement. In the event
that Schwab does not reject the proposed change or modification, Aether
represents, warrants and covenants that, with respect to matters under Aether's
sole control, any such conversion of the Wireless System or its features will
not cause: (a) any material delay or interruption of performance; (b) material
loss or corruption of data; or (c) material incompatibilities with any software
or hardware with which the applicable Wireless System is to be provided or used,
including, but not limited to, (1) encryption or other security-related

                                  Confidential
                                  Page 3 of 21
<PAGE>   4

systems provided by third parties; and (2) any portion of Schwab's or the
applicable end users' hardware, software, or browser configurations. Without
limiting the foregoing, with respect to each major upgrade or new version of a
Wireless System, Aether shall provide to Schwab, upon Schwab's reasonable
request, such onsite professional services during normal business hours as
requested to effect the installation and integration of the upgrade or new
version.

     1.6 AETHER RIGHT OF FIRST REFUSAL ON NEW DEVELOPMENTS. If at any time
during the term of this Agreement, the mobile trading team within Schwab's
Electronic Brokerage Enterprise decides to have a party other than Schwab or any
Schwab Affiliate (as defined in Section 2.4 below) produce, develop, manufacture
or otherwise create for any Schwab Service a wireless product or service
involving the use of Handheld PCs ("HPCS") or Handheld Digital Personal
Assistants ("PDAS"), or substantially similar devices, Schwab shall so notify
Aether in writing. For a period of six weeks thereafter, Schwab shall negotiate
exclusively and in good faith with Aether regarding the terms and conditions
upon which Aether shall provide such products, services or technologies. If
Aether and Schwab have not, at the end of such six week period, executed a new
WP Schedule or Change Order relating to Aether's provision of such products,
services or technologies, Schwab may negotiate with one or more third parties
regarding the provision of such products, services or technologies; provided,
however, that the mobile trading team within Schwab's Electronic Brokerage
Enterprise may not enter into an agreement with a Comparable Third Party (as
defined below) to provide such products, services or technologies on terms
substantially more favorable to such third party than those terms offered to
Aether in the aforementioned negotiations with Aether. If Schwab desires to
retain such a Comparable Third Party to provide such products, services or
technologies on terms substantially more favorable than offered to Aether, such
new terms will be subject to Aether's right of first refusal as set forth
hereunder. As used in this Section 1.6, the term "COMPARABLE THIRD PARTY" refers
to any entity or individual that possesses, in Schwab's reasonable opinion, a
substantially equivalent degree of expertise, resources and/or name recognition
in connection with the new development under consideration.

     1.7 SCHWAB INTERNAL DEVELOPMENT. When the mobile trading team within
Schwab's Electronic Brokerage Enterprise deems it appropriate, in its
reasonable discretion, it will consult with Aether regarding its efforts to
develop wireless services or products not included within an existing WP
Schedule. Nothing in this Agreement will limit Schwab's right to internally
develop and offer products and services that have the same or similar
functionality as a Wireless System subject to this Agreement, to reproduce and
distribute any products or services (including without limitation Wireless
Systems) to Schwab Users either with or without Aether so long as such
activities do not violate any of Aether's ownership rights under this Agreement
or any applicable WP Schedule. Except as specifically provided with respect to a
particular WP Schedule, Schwab is free to use any ideas, concepts, know-how, or
techniques derived directly or indirectly from any Wireless System, other
services provided by Aether, or Aether's retention under this Agreement for any
purpose whatsoever, including, but not limited to, developing and offering
products or services using such information.

     1.8 SCHWAB RIGHT OF FIRST REFUSAL. Upon receipt of a bona fide written
offer (an "OFFER") to purchase (1) a Wireless System subject to this
Agreement, or (2) any newly developed products, services or technologies
relating to a wireless data access system that may have an application in
providing financial services (collectively, the "OFFERED ASSETS"), which

                                  Confidential
                                  Page 4 of 21
<PAGE>   5

offer Aether would otherwise accept but for this right of first refusal, Aether
will within ten (10) business days thereafter deliver to Schwab written notice
accompanied by a copy of the Offer, which will include the terms, conditions,
pricing or valuation of consideration for the sale of the Offered Assets (the
"NOTICE OF OFFER"). If part of or all of the consideration for the Offered
Assets included in the Offer consists of non-cash consideration, the Notice of
Offer will state the cash value of such non-cash consideration. For a period of
twenty (20) days after receipt of the Notice of Offer, Schwab will have the
right to purchase the Offered Assets on the same terms and conditions, including
price, as the Offer by giving written notice of purchase to Aether. If Schwab
does not exercise its right to purchase the Offered Assets pursuant to this
Section 1.8 within twenty (20) business days after receipt of the Notice of
Offer, Aether may sell the Offered Assets pursuant to the terms of the Offer, on
terms (including purchase price) not materially more favorable to the bona fide
purchaser than the terms set forth in the Offer. If Aether desires to sell the
Offered Assets on terms materially more favorable than set forth in the Offer,
such new terms will be subject to Schwab's right of first refusal as set forth
hereunder.

                                       II.

                               PROPRIETARY RIGHTS

     2.1 SCHWAB INTELLECTUAL PROPERTY. Unless expressly reserved to Aether
within the applicable WP Schedule, all intellectual property conceived,
created, made, invented, or discovered in connection with a Wireless System
subject to this Agreement (collectively, the "WORKS"), whether conceived,
created, discovered, made, or invented individually or jointly with others, will
be and remain the absolute property of Schwab, as will all the worldwide patent,
copyright, trade secret, or other intellectual property rights in all such
Works. Aether irrevocably and unconditionally waives all rights that vest in
Aether or any of its affiliates (whether before, on, or after the date of this
Agreement) in connection with Aether's or of any of its affiliate's authorship
of any such copyrightable Works.

     2.2 AETHER RESERVED INTELLECTUAL PROPERTY. All Works (as defined in Section
2.1 above) that are expressly reserved by Aether within the applicable WP
Schedule, are and will be the property of Aether ("AETHER RESERVED INTELLECTUAL
PROPERTY").

     2.3 LICENSE OF AETHER RESERVED INTELLECTUAL PROPERTY. In each occasion
where a WP Schedule contains Aether Reserved Intellectual Property, Aether
will grant to Schwab such licenses within the applicable WP as necessary for
Schwab's use of the applicable Wireless System as contemplated by the
corresponding WP Schedule.

     2.4 ASSIGNMENT AND TRANSFERS OF WIRELESS SYSTEMS. Unless otherwise
provided in an applicable WP Schedule, Schwab may not assign, transfer or
sub-license the license of a Wireless System governed by this Agreement, except
to legal entities conducting financial services which Schwab controls, is
controlled by, or is under common control with, where "control" means the
direct or indirect ownership of at least 20% of the outstanding equity of such
entity (a "SCHWAB AFFILIATE"). Schwab may assign, transfer or sub-license its
rights under this Agreement, including the license to use a Wireless System, to
Schwab Affiliates who

                                  Confidential
                                  Page 5 of 21
<PAGE>   6

are not competitors of Aether, within Aether's reasonable judgment, upon 30
days' prior notice to Aether.

     2.5 ACCESS TO THIRD PARTIES. Both parties acknowledge and agree that no
third party, including without limitation, Schwab Users, is granted
permission to retain, modify, copy, or distribute any of the other's
intellectual property that is accessed via a Wireless System, other than as
expressly provided in the applicable WP Schedule. Each party will use
commercially reasonable efforts to prevent third parties from (a) modifying a
Wireless System or any portion thereof, (b) copying or duplicating a Wireless
System, (c) renting, selling, leasing or otherwise transferring a Wireless
System or any part thereof or use it for the benefit of any third party, (d)
removing, obscuring, altering or failing to reproduce any notices, designations
or other marks, (e) reverse assembling, reverse compiling or reverse engineering
a Wireless System, or otherwise attempting to discover or use any source code or
any other intellectual property, (f) marketing or selling all or a portion of a
Wireless System or (g) allowing the use of or access to a Wireless System to
anyone other than an individual or entity approved for such use or access by
Schwab in accordance with the applicable WP Schedule. Each party will promptly
notify the other in writing of any such retention, modification, copying, or
distribution of which it obtains actual knowledge or has reason to believe, and
each party agrees that it will immediately use commercially reasonable efforts
to terminate the access to the applicable Wireless System of anyone who causes
such retention, modification, copying, or distribution.

     2.6 OWNERSHIP OF USER INFORMATION. As between Schwab and Aether, User
Information (as'defined herein) is and will remain the sole and exclusive
property of Schwab. "USER INFORMATION" means all data information pertaining to
or identifiable to a Schwab User including without limitation, (i) name,
address, email address, passwords, personal financial information, personal
preferences; demographic data; marketing data; data about securities
transactions; credit data, or any other identification data; (ii) any
information that reflects a Schwab User's interactions with a Schwab web site,
including but not limited to, information concerning computer search paths, any
profiles created or general usage data; or (iii) any data otherwise submitted by
a Schwab User in the process of registering for the a Schwab web site (such as
name, address, phone number an email address) and data submitted during the
course of using a Schwab web site. Nothing in this Agreement will be construed
as granting any ownership rights in Aether to User Information. However, Aether
may receive or use User Information for the purposes contemplated by this
Agreement, and if Aether learns or obtains any User Information, Aether will
treat such User Information as proprietary and confidential to Schwab in
accordance with this Agreement, whether or not Schwab intentionally disclosed
such User Information to Aether.

     2.7 OWNERSHIP OF DOMAIN NAMES. Each party will retain all right, title and
interest in and to, and ownership of, their own respective Domain Names,
and the other party will not acquire any right, title, or interest therein. Each
party acknowledges that the Domain Names will be associated with the respective
parties and/or their affiliates and that each party will build up substantial
goodwill in the Domain Names and, accordingly, that the Domain Names will be a
valid trademark and/or service mark of the respective parties and/or their
affiliates.

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<PAGE>   7

     2.8 STATUTORY RIGHTS. Except as expressly provided in this Agreement or
within an applicable WP Schedule, nothing in this Agreement will diminish
either party's rights in any property or technology owned by such party (or its
licensors) under any applicable law governing intellectual property rights.

                                      III.

                     GENERAL REQUIREMENTS FOR THE OPERATION
                       AND MAINTENANCE OF WIRELESS SYSTEMS

     3.1 INTENT OF THE PARTIES. The parties hereto acknowledge that Aether's
obligations under this Agreement with respect to Wireless Systems are and
will relate primarily to providing the connectivity and associative support
services to enable Schwab Users to access certain data and execute certain
transactions through wireless devices. The parties do not intend for Aether to
be deemed a broker or dealer or be involved in the effecting of any securities
transactions. With respect to all Wireless Systems governed by this Agreement,
Schwab accepts the following responsibilities in connection with the use and
operation of such Wireless Systems:

          a. SCREENING CUSTOMER ACCESS AND TRANSACTIONS. Schwab will be solely
responsible for determining whether to grant access to a Wireless System to a
particular Schwab User, subject only to any licensing restrictions contained in
a corresponding WP Schedule.

          b. EFFECTING CUSTOMERS' SECURITIES TRANSACTIONS. Schwab will be
responsible for accepting and supervising each securities order and continuing
securities transaction and securities accounts to assure compliance with its
regulatory responsibilities under applicable securities laws. Schwab will be
solely responsible for notifying Aether of any modifications necessary
to fulfill Schwab's legal and regulatory responsibilities.

     3.2 STANDARD OF PERFORMANCE. Aether warrants to Schwab that it will
maintain an adequate number of personnel who are qualified and responsive for
the term of this Agreement and perform each Wireless Project in accordance at
the highest level of service that Aether delivers to its other customers and in
accordance with generally accepted professional standards for similar services
in effect at the time of such performance. Without limiting the foregoing,
Aether will provide prompt and professional responses to all Schwab requests and
will fulfill the service levels set forth in the applicable WP Schedule.

     3.3 QUALITY CONTROL. Aether shall institute quality controls, including
suitable testing procedures, if any, to ensure the availability of all Wireless
Systems developed and/or maintained by this Agreement and to ensure that such
Wireless Systems perform in accordance with the applicable specifications and in
a manner consistent with the highest applicable industry standards. Upon
Schwab's reasonable request, Schwab will have the right to review Aether's
quality controls in order to verify and/or improve the quality of the Wireless
Systems and the Wireless Systems' performance.

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<PAGE>   8

     3.4 OPERATIONAL AND MAINTENANCE REQUIREMENTS. Each party will carry out and
complete the duties and responsibilities with respect to operating, maintaining
and/or supporting a Wireless System as set forth in the applicable WP Schedule.

     3.5 TRAINING SERVICES. With respect to all Wireless Systems, Aether will
provide sufficient training and technical support to Schwab to enable its
personnel to properly use the Wireless System. Such training shall be described
in the applicable WP Schedule. Schwab may reproduce any training material
provided by Aether for the purpose of training Schwab's personnel. Any such
reproduction shall include any applicable copyright or similar proprietary
notices contained in the items being reproduced.

     3.6 PROVIDING ACCESS TO DATA. With respect to each Wireless System, Aether
will take all commercially reasonable steps necessary for Schwab to have
immediate and continuous access to such data as is necessary and desirable for
Schwab to fulfill its responsibilities as a broker-dealer under federal and
state laws and the rules and regulations of applicable self-regulatory
organizations.

     3.7 MAINTENANCE OF BOOKS AND RECORDS. Aether will design and maintain each
Wireless System in a manner that Schwab may continue to maintain books and
records of all transactions in an account executed, cleared or settled through
or by Schwab in accordance with the generally accepted practices in the
securities industry and as required by all applicable laws and regulations.

     3.8 INCLUSION OF THIRD PARTY MATERIAL. Aether agrees that it will, at
Schwab's request, make the financial information identified as "THIRD PARTY
MATERIAL" within the applicable WP Schedule accessible through the corresponding
Wireless System. Schwab understands that Aether will obtain such financial
information from various independent third parties, such as stock exchanges and
others. Aether does not guarantee or warrant such information. There may be
delays, omissions or inaccuracies in the information. Aether will not have any
liability, contingent or otherwise, for such information, or for any decision
made or taken by Schwab or any of its customers, including without limitation
Schwab Users, in reliance upon such information or for the interruption of any
data, information or other aspect of such information. Except as expressly
provided in the applicable WP Schedule, no person accessing a Wireless System,
including without limitation Schwab and Schwab Users, will have any rights to
use, transmit or re-transmit any such information, and no person, including
without limitation Schwab and Schwab Users, will acquire any rights to such
information, except in accordance with this Agreement.

     3.9 REGULATORY APPROVALS. Aether will be solely responsible for obtaining
approvals for the initial and continued use of each Wireless System that may be
required by state and/or federal authorities.

     3.10 COMPLIANCE AND INSPECTION RIGHTS. Each party will have the right, but
not the duty, of unrestricted access to inspect and review the Wireless Systems
governed by this Agreement in a manner consistent with their respective
responsibilities under this Agreement, any supervisory responsibilities under
state and federal law and the rules and regulations of applicable
self-regulatory organizations.

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<PAGE>   9

     3.11 ADVERTISING AND LINKS. Aether will not permit any advertisements
within or links to a Wireless System without the prior written consent of
Schwab.

     3.12 USAGE INFORMATION. Aether will, upon request, provide Schwab with all
information reasonably available regarding usage of the Wireless Systems
governed by this Agreement.

     3.13 OUTSOURCING. Aether may use independent contractors who are natural
persons in fulfilling its duties under this Agreement provided that Aether will
be responsible and liable for such independent contractors and will obtain
confidentiality agreements from such independent contractors. Such
confidentiality agreements must contain: (i) provisions which require that the
independent contractor comply with the terms and conditions of Article VII of
this Agreement; and (ii) language providing that Schwab may enforce its rights
against the independent contractor as an intended third party beneficiary of
such agreement, even though Schwab is not a party to such agreement, provided
that Schwab's right to exercise such rights will be conditioned on its having
given Aether reasonable prior written notice of Schwab's intention to do so, and
specific reasons for doing so, such that Aether has a reasonable opportunity to
resolve the issue that Schwab has with such independent contractor. Otherwise,
Aether may not assign or delegate this Agreement nor any of its rights, duties
or obligations under this Agreement without the express written consent of
Schwab which may be conditioned upon certain terms. Any purported assignment or
delegation in violation of this provision shall be void at the option of Schwab.
Schwab's consent shall not be deemed an endorsement of such assignment or
delegation and shall not relieve Aether of any of its obligations or liabilities
under this Agreement. Any such assignment, delegation or subcontracting, even if
approved by Schwab, will be at Aether's own risk and expense.

                                       IV.

                                 INDEMNIFICATION

     4.1 INDEMNIFICATION. Each party (the "INDEMNIFYING PARTY") will indemnify
and hold harmless the other, its affiliates, successors and assigns and the
directors, officers and employees and agents of any of them (each an
"INDEMNIFIED PARTY"), from any claim, loss, damage, expense or liability arising
out of incurred by any such person due to or arising out of (1) the breach of
the obligations, representations, or warranties contained in this Agreement, (2)
as a result of any claim or assertion that the Indemnifying Party has infringed
or violated the intellectual property rights of any third party or (3) the gross
negligence or willful misconduct of the Indemnifying Party or its directors,
officers or employees, except to the extent arising out of or based on any
grossly negligent act or omission of an Indemnified Party with respect to the
subject matter of this Agreement; provided that the Indemnified Party provides
the Indemnifying Party with (i) prompt written notice of such claim or action,
(ii) sole control and authority over the defense and over the defense or
settlement of such claim or action, and (iii) proper and full information and
reasonable assistance to defend and/or settle any such claim or action.

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                                       V.

                                FEES AND PRICING

     5.1 FEES AND EXPENSES. During the term of this Agreement, Schwab will pay
to Aether the fees specified in the applicable WP Schedule for the corresponding
Wireless System and any other products and services specified therein. Aether
will create detailed invoices, listing each WP Schedule, and each fee and
calculation for that fee. Aether will forward detailed invoices to Schwab for
payment whenever agreed upon fees are incurred, but not more frequently than
every thirty (30) days. Upon receipt of an invoice, Schwab will process it in
the normal course of business and pay within thirty (30) days.

     5.2 NO OTHER PAYMENTS. Except as specified in an applicable WP Schedule,
Schwab will not be obligated to make any payments to Aether for any products or
services under this Agreement, unless otherwise agreed to by Schwab in writing
after the date of this Agreement. In particular, unless otherwise specified in
an applicable WP Schedule, Aether will be responsible for the costs associated
with developing, installing, maintaining, operating, accessing and/or using a
Wireless System in accordance with Schwab's recommendations and/or compatibility
requirements.

     5.3 MOST FAVORED STATUS. If during the course of this Agreement, Aether
provides a Wireless System (or services or products that are substantially
similar in scope, functionality, resources, and user base) to any comparable
customer on more favorable terms and conditions than those then in place with
Schwab, then notwithstanding any arrangement then in place with Schwab, Schwab
shall be entitled to the more favorable terms as of the effective date of such
comparable customer agreement. Aether shall notify Schwab in writing of the
applicable terms of such comparable customer agreement within thirty (30)
calendar days following the execution of any such comparable customer agreement
and shall be obligated disclose, unless contractually prevented from doing so,
the identity of any such comparable customer. In the event that payment has been
made by Schwab prior to notice from Aether, Schwab shall be entitled to a credit
adjustment in the next statement of costs and fees from Aether retroactive to
the date of the effective date of Aether's agreement with said comparable
customer.

     5.4 RENEWAL PRICING. In the event that a WP Schedule is renewed beyond the
initial term (as defined within the applicable WP Schedule), the parties agree
that they will negotiate in good faith to set renewal pricing for maintenance
and support and for the cost of any new version of the applicable Wireless
System.

     5.5 TAXES. Aether will pay all taxes due on the payments Aether receives
under this Agreement, including sales and use tax, if any.

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<PAGE>   11

                                       VI.

                         REPRESENTATIONS AND WARRANTIES

     6.1 RECIPROCAL WARRANTIES. Aether and Schwab each represent and warrant
with respect to itself as follows: (a) such party is duly organized, validly
existing, and in good standing under the laws of the state in which it is
organized, and has the power and authority to carry on its business as now being
conducted, (b) such party has the financial resources, personnel and
organizational resources to perform its obligations under this Agreement and
will notify the other of any change in such party's circumstances that would
materially adversely impact its ability to perform its obligations under this
Agreement, (c) that there is no action, suit or proceeding before or by any
court or governmental agency or body or otherwise, now pending, or to the
knowledge of each party, threatened against or affecting such party or its
property that may result in a material adverse change in the condition,
financial or otherwise or business prospects of such party, and (d) this
Agreement has been duly executed and delivered on behalf of such party and is a
legal and binding obligation of such party enforceable against it in accordance
with the terms of this Agreement except (i) as the same may be limited by
bankruptcy, insolvency, reorganization, or other laws or equitable principles
relating to or affecting the enforcement of creditors' rights and (ii) that the
availability of equitable remedies including specific performance is subject to
general equitable principles applied at the discretion of a court.

     6.2 REPRESENTATIONS OF SCHWAB. In connection with its activities hereunder,
Schwab represents and warrants to Aether that:

          a. Schwab is and will remain properly registered as a broker-dealer
with the SEC and each state, territory and jurisdiction in which it is subject
to registration, licensing, qualification and/or certification requirements for
the duration of this Agreement;

          b. Schwab will comply fully with the terms and conditions set forth in
this Agreement and with all applicable statutes, rules and regulations in any
jurisdiction in which it will offer and provide retail, wireless data access
and transaction services under this Agreement;

          c. Schwab has obtained all required governmental and regulatory
licenses, registrations and approvals as may be necessary for it to offer and
provide wireless data access and transaction services under the terms of this
Agreement; and

          d. Schwab represents and warrants that it will offer and provide
wireless data access and transaction services in a manner consistent with all
federal and state laws and the rules and requirements of the SEC, the NYSE and
all other applicable self-regulatory agencies.

     6.3 REPRESENTATIONS OF AETHER. In connection with its activities hereunder,
Aether represents and warrants to Schwab that:

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<PAGE>   12

         a. Aether is highly skilled and experienced in developing a suite of
technologies, competencies and services for the enabling of wireless data
communication access supporting multiple wireless data networks, information
appliance devices and server technologies, and Aether also possesses the
additional expertise needed to develop such Wireless Systems for Schwab as
contemplated by this Agreement;

         b. Aether will comply fully with the terms and conditions set forth in
this Agreement and with all applicable statutes, rules and regulations in any
jurisdiction in which it will offer and provide wireless communication services
under this Agreement;

         c. Aether has obtained all required governmental and regulatory
licenses, registrations and approvals as may be necessary for it to offer and
provide wireless communication services under the terms of this Agreement;

         d. Without limiting any other warranty or obligation specified in this
Agreement, or in any other agreement, Aether expressly warrants to Schwab
that the Wireless Systems governed by this Agreement, including all related
software, and all services furnished under this Agreement will at all times be
Year 2000 Compliant. "YEAR 2000 COMPLIANT" means that the Wireless Systems and
services will operate and: (i) will correctly store, represent, and process
(including sort) all dates (including single and multi-currency formulas and
leap year calculations), such that errors will not occur when the date being
used is in the Year 2000, or in a year preceding or following the Year 2000; and
(ii) will not cause or result in an abnormal termination or ending. Aether
further warrants that in providing the Wireless Systems and services to Schwab,
all of Aether's information processing services are and at all times will be
Year 2000 Compliant;

         e. To Aether's knowledge, the System does not and will not infringe or
violate the intellectual property rights of any third party;

         f. On the date that it executes this Agreement, Aether is not located
in a foreign country, acting on behalf of or in concert with any foreign person
or foreign government or attempting in any way to evade U.S. export controls on
encryption; and

         g. The Wireless Systems, including without limitation their
corresponding software:

          (i) will not contain viruses, Trojan horses, worms, time bombs,
cancelbots or other similar harmful or deleterious programming routines; and

          (ii) will transmit all data and information to Schwab and applicable
end users without damage, corruption or other changes save and except for the
encryption of such information as applicable.

     6.4 DISCLAIMERS. Except as expressly provided in this Agreement or any
applicable WP Assignment, neither party makes any warranty of any nature
whatsoever regarding a Wireless System, including without limitation, any
warranty of Merchantability, Fitness for a Particular Purpose or compliance with
law or specifications.

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<PAGE>   13

                                      VII.

                      CONFIDENTIALITY AND NON-SOLICITATION

     7.1 DEFINITION OF CONFIDENTIAL INFORMATION. Each party agrees that all
information supplied by one party to the other including, without limitation,
(i) source code, prices, databases, hardware, software, programs, engine
protocols, models, displays and manuals, including, without limitation, the
selection, coordination, and arrangement of the contents thereof and (ii) any
unpublished information concerning research activities and plans, marketing or
sales plans, pricing or pricing strategies, operational techniques, strategic
plans, the identity of customers and customer contacts, customer data, and
unpublished financial information, including information concerning revenues,
profits and profit margins will be deemed confidential and proprietary to the
supplying party ("CONFIDENTIAL INFORMATION").

      7.2 TREATMENT OF CONFIDENTIAL INFORMATION. Each party recognizes the
importance of the other's Confidential Information. In particular, each party
recognizes and agrees that the Confidential Information of the other is critical
to their respective businesses and that neither party would enter into this
Agreement without assurance that such information and the value thereof will be
protected as provided in this Section 7.2 and elsewhere in this Agreement.
Accordingly, each party agrees as follows:

          a. Each party will hold any and all Confidential Information it
obtains in strictest confidence and shall use and permit use of Confidential
Information solely for the purposes of this Agreement (a "PERMITTED PURPOSE");

          b. Each party may disclose or provide access to its responsible
employees, and may make copies, of Confidential Information only to the extent
reasonably necessary to carry out Permitted Purposes;

          c. Each party currently has, and in the future shall maintain in
effect and enforce, rules and policies to protect against access to or use or
disclosure of Confidential Information other than in accordance with this
Agreement, including without limitation written instruction to and agreements
with employees to ensure that such employees protect the confidentiality of
Confidential Information. Each party expressly shall instruct its employees not
to disclose Confidential Information to third parties, including without
limitation customers, subcontractors or consultants, without the other's prior
written consent;

          d. Each party, at its own expense, shall take all steps, including
without limitation the initiation and prosecution of actions at law or in
equity, necessary or appropriate to prevent use or disclosure, and upon any
unauthorized disclosure further unauthorized disclosure or use, of any
Confidential Information received or obtained by it except as expressly
permitted by the terms of this Agreement;

          e. Neither party will copy (other than regular backup copies), modify,
disassemble, reverse engineer or decompile any of the other's Proprietary
Information;

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<PAGE>   14
          f. Neither party will make any use whatsoever at any time the other's
Confidential Information except as expressly authorized in this Agreement; and

          g. Each party will notify the other immediately of any unauthorized
disclosure or use, and will cooperate with that party to protect all proprietary
rights in and ownership of its Confidential Information.

     7.3 EXCLUSIONS. Confidential Information will not include any information
or material, or any element thereof, whether or not such information or material
is Confidential Information for the purposes of this Agreement, to the extent
any such information or material, or any element thereof:

          a. has been previously published or is published hereafter, unless
such publication is a breach of this Agreement or a similar non- disclosure
agreement;

          b. was already known to the disclosing party prior to being disclosed
by or obtained from the other party as evidenced by written records kept in the
ordinary course of business of or by proof of actual use by the disclosing
party;

          c. has been or is hereafter rightfully received by the disclosing
party from a third person (other than the other party) without restriction or
disclosure and without breach of this Agreement; or

          d. has been independently developed by the disclosing party.

It shall be presumed that any Confidential Information in a disclosing party's
possession is not within exceptions (b), (c) or (d) above, and the burden shall
be upon the disclosing party to prove otherwise by records and documentation.

     7.4 COMPELLED DISCLOSURES. To the extent required by applicable law or by
lawful order or requirement of a court, governmental authority or
self-regulatory agency having competent jurisdiction over the disclosing party,
the disclosing party may disclose Confidential Information in accordance with
such law or order or requirement, subject to the following conditions: As soon
as possible after becoming aware of such law, order or requirement and prior to
disclosing Confidential Information pursuant thereto, the disclosing party shall
so notify the other party in writing and, if possible, the disclosing party
shall provide the other party notice not less than five (5) business days prior
to the required disclosure. The disclosing party shall use reasonable efforts
not to release Confidential Information pending the outcome of any measures
taken by the other party to contest, otherwise oppose or seek to limit such
disclosure by the disclosing party and any subsequent disclosure or use of
Confidential Information that may result from such disclosure. The disclosing
party shall cooperate with the other party regarding such measures.
Notwithstanding any such disclosure, the disclosing party shall not affect its
obligations hereunder with respect to Confidential Information so disclosed.

     7.5 TREATMENT OF USER INFORMATION. Without limiting any other warranty or
obligation specified in this Agreement, an in particular Section 7.2 of this
Agreement, during the

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<PAGE>   15


term of this Agreement and thereafter in perpetuity, Aether will not gather,
store, or use any User Information (as defined in Section 2.6 of this Agreement)
in any manner and will not disclose, distribute, sell, share, rent or otherwise
transfer any User Information to any third party, except as Aether may be
expressly and reasonably directed in advance in writing by Schwab. Aether
represents, covenants, and warrants that Aether will use User Information only
in compliance with Schwab's written instructions, including without limitation
its privacy policies then in effect and all applicable laws (including but not
limited to policies and laws related to spamming, privacy (including but not
limited to any European privacy laws), and consumer protection. Aether hereby
agrees to indemnify and hold hannless Schwab against any damages, losses,
liabilities, settlements and expenses (including without limitation costs and
attorneys' fees) in connection with any claim or action that arises from an
alleged violation of the foregoing.

     7.6 RETENTION OF USER INFORMATION. Aether will not retain any User
Information for any period longer than necessary for Aether to fulfill its
obligations under this Agreement. As soon as Aether no longer needs to retain
such User Information in order to perform its duties under this Agreement,
including an applicable WP Schedule, Aether will return such User Information in
accordance with Section 7.8 of this Agreement.

     7.7 NON-EXCLUSIVE EQUITABLE REMEDY. Each party acknowledges and agrees that
due to the unique nature of Confidential Information, there can be no adequate
remedy at law for any breach of its obligations hereunder, that any such breach
may allow a party or third parties to unfairly compete with the other party
resulting in irreparable harm to such party, and therefore, that upon any such
breach or any threat thereof, each party will be entitled to appropriate
equitable relief from a court of competent jurisdiction in addition to whatever
remedies either of them might have at law or equity before a panel of
arbitrators appointed in accordance with the arbitration provision of this
Agreement and to be indemnified by the other party from any loss or harm,
including, without limitation, lost profits and attorneys' fees, in connection
with any breach or enforcement of such party's obligations hereunder or the
unauthorized use or release of any such Confidential Information. Each party
will notify the other in writing immediately upon the occurrence of any such
unauthorized release or other breach. Any breach of this Article VII will
constitute a material breach of this Agreement and be grounds for immediate
termination of this Agreement in the exclusive discretion of the non-breaching
party.

     7.8 RETURN OF CONFIDENTIAL INFORMATION. On written request or on the
termination of this Agreement, each party will (i) return to the other or
destroy the tangible embodiment of the other's Confidential Information in its
possession or control; and (ii) provide written confirmation of such party's
compliance with this provision.

     7.9 NON-SOLICITATION. During the term of, and for one year after
the termination of this Agreement, Aether will not, directly or indirectly,
knowingly solicit the employment or services of any employee or consultant of
Schwab with whom Aether has had contact or who became known to it in connection
with this Agreement, or encourage such employees or consultants to leave Schwab.
This Section will not preclude Aether from undertaking general, public
solicitations for employees.

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                                      VIII.

                            PROMOTIONS AND MARKETING

     8.1 MARKETING PLAN. Each WP Schedule will address the respective
obligations of each party, if any, with respect to promoting and marketing the
corresponding Wireless System.

     8.2 REVIEW OF PROMOTIONAL MATERIAL. Aether will not disclose, publish, or
otherwise distribute any promotional, sales, marketing, advertising, and similar
materials referring to Schwab or this Agreement, or to any trade name,
trademark, service or product of Schwab in any form or medium, including but not
limited to, news releases, advertising scripts, direct mail correspondence,
customer list, and display advertising, without Schwab's prior written approval,
which Schwab may withhold in its sole and absolute discretion.

     8.3 USE OF MARKS. Each party grants to the other a non-exclusive,
non-transferable license to use its respective trade names, trademarks, service
marks and/or logos (a "MARK") during the term of this Agreement in connection
with marketing, promotion and advertising; provided, that when used in printed
materials, the Mark will be footnoted upon its appearance with a legend that
such Mark is a registered Mark of the other.

     8.4 OWNERSHIP OF MARKS. Each party acknowledges that the other is the sole
owner of its respective Marks and agrees that it will take no action to
challenge or undermine that party's rights or title to the Mark anywhere in the
world. Each party will cooperate with the other's efforts to protect and
register its respective Marks. In addition:

          a. A party may only use the other's Mark in its standard form and
style as used or authorized in writing by that party. Except as set forth in
this Agreement, no other letter(s), word(s), design(s), symbol(s), or other
matter of any kind may be superimposed upon, associated with or shown in such
proximity to a Mark so as to tend to alter or dilute it, and each party
specifically agrees not to combine or associate the Mark with any other mark or
trade name.

          b. In all advertisements, promotional literature or other printed
matter in which a Mark appears, each party must identify itself by full name and
address and state its relationship other. The Mark must be identified as a Mark
owned by the respective party, in a form and manner approved by the other party;

          c. Neither party warrants or represents that the other's use of such a
Mark will not infringe the trademark rights other persons. In the event that
either party is subject to a claim or action, or learns any facts that make such
a claim or action reasonably possible, it will notify the other and the parties
will negotiate in good faith a solution, including the adoption by a party of
new names or marks to identify itself or its business in the territories where
problems exist. All such new marks or names will be deemed Marks for purposes of
this Agreement; and

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<PAGE>   17




          d. Each party will maintain the quality of the other's Mark in
connection with its usage and placement during the term of this Agreement and in
a manner consistent with the industry practices with respect to brokerage
activities. Each party reserves the right to monitor the services provided under
this Agreement to assure compliance with the standards for services associated
with their respective Trademarks.

     8.5 SOLICITATION OF SCHWAB USERS. During the term of this Agreement and
thereafter in perpetuity, Aether agrees not to knowingly target or solicit
Schwab Users as such, on behalf of itself or any third party, including but not
limited to, on behalf of entities that provide brokerage or financial services
in direct competition with Schwab. Aether agrees that it will not use or sell to
others lists containing information obtained in connection with this Agreement
about any Schwab Users. This Section will not preclude Aether from undertaking
general, public solicitations for customers.

     8.6 PROMOTION OF COMPETING SERVICES. During the term of this Agreement,
Aether agrees not to promote directly or indirectly through a Wireless System
governed by this Agreement, the services of itself or of any third party. Unless
requested by Schwab in writing, the content and a Wireless System governed by
this Agreement will contain no advertising or other promotional material except
that specifically authorized by Schwab pursuant to this Agreement.

     8.7 IDENTIFICATION OF AETHER. Schwab agrees to identify Aether as Schwab's
"Wireless Data Service Provider" for all Schwab wireless products and service
offerings through PDAs and HPCs (as defined above) by Schwab's Electronic
Brokerage Enterprise to Schwab retail brokerage customers, except for both
one-way and two-way pagers, during the two (2) year period following the
Effective Date of this Agreement.

                                       IX.

                                   TERMINATION

     9.1 TERM. This Agreement will be effective as of the Effective Date and
will continue in full force for as long as there are WP Schedules in effect
under this Agreement.

     9.2 TERMINATION ON BREACH OF LAW. If either party is in material default
under any rule, order, determination, ordinance, or law of any federal, state,
county, municipal or self-regulatory authority and that party is not in good
faith contesting the default, the non-defaulting party may terminate this
Agreement at any time thereafter.

     9.3 TERMINATION ON BREACH OF AGREEMENT. If an Event of Default (as defined
herein) occurs under this Agreement, and if, within 30 days after the
non-defaulting party has given the defaulting party notice of the Event of
Default, the defaulting party has not cured the default or, if the default
cannot be reasonably cured within such time period, the non-defaulting party
may, at its option, terminate this Agreement at any time thereafter. Each of the
following will constitute an "EVENT OF DEFAULT" under this Agreement:

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          a. Any party fails to perform or observe to the reasonable
satisfaction of the other party any term, a material covenant or undertaking in
this Agreement;

          b. Any party informs the other party of its intention not to perform
or observe a term of this Agreement;

          c. Any material warranty, representation or other statement made by or
on behalf of one party and contained in this Agreement or in any other document
furnished in compliance with or in reference to this Agreement is on the date
made or later proves to be false, misleading or untrue in any material respect;
or

          d. Any party seeks protection under the United States Bankruptcy Code
or similar protection from creditors; or bankruptcy, receivership, insolvency,
reorganization, dissolution, liquidation or other similar proceedings will be
instituted by or against the non-termination party and not dismissed.

     9.4 TERMINATION OF WIRELESS PROJECTS. Unless otherwise stated in an WP
Schedule, Schwab may terminate a Wireless Project, for any reason whatsoever,
with respect to all WP Schedules under this Agreement by not less than thirty
(30) days written notice to Aether, specifying the date upon which termination
become effective. In the event of any termination of an Wireless Project, Aether
will be entitled to payment for services actually rendered by Aether prior to
the effective date of termination, in accordance with this Agreement and/or the
applicable WP Schedule. Such payment will constitute full settlement of any and
all claims of Nimble for payment under the WP Schedule, including without
limitation, claims for lost profits.

     9.5 SCHWAB'S TERMINATION. Schwab may terminate this Agreement at its option
without breach or penalty if Aether or any of its affiliates: (a) registers as
or acquires or merges with a broker-dealer; or (b) merges with or sells
substantially all of its assets to another party that Schwab reasonably believes
to be a competitor.

     9.6 EFFECTS OF TERMINATION. Upon any termination or expiration of this
Agreement:

          a. Schwab will, within a commercially reasonable period, cease use of
all Wireless Systems and use all reasonable commercial means to terminate access
by applicable Schwab Users;

          b. Aether will use commercially reasonable efforts to prevent Schwab
Users from using or accessing the terminated Wireless Systems and will cooperate
with Schwab, at Schwab's expense, in implementing and maintaining a
discontinuation notice for sixty (60) days following expiration or termination
of the applicable Wireless Systems.

          c. No consideration or indemnity will be payable to either party for
loss of profit, goodwill, creation of clientele or other like or unlike items,
nor for advertising

                                  Confidential
                                  Page 18 of 21


<PAGE>   19


costs, costs of samples or supplies, termination of employees, employees'
salaries and other like or unlike items;

          d. Each party will return or destroy all the Confidential Information
in its possession and control and so certify to the other party in writing; and

          e. Neither party will incur any liability whatsoever for any damage,
loss or expense of any kind suffered by the other arising from or incidental to
any termination of this Agreement which complies with the terms of this
Agreement whether or not such party is aware of any such damages, losses or
expense.

     9.7 SURVIVAL. All accrued payment obligations hereunder, any remedies
for breach of this Agreement, this Section and the following Sections will
survive any expiration or termination of this Agreement: Article II (Proprietary
Rights); Article IV (Indemnification); Article VII (Confidentiality and
Non-Solicitation); Article VIII (Promotions and Marketing); Article IX, Section
9.6 (Effect of Termination); Article X (General Provisions), and termination
shall not affect a party's right to claim a breach of representation and
warranties of this Agreement.

                                       X.

                               GENERAL PROVISIONS

     10.1 NOTICES. Any notice, notification, demand or request provided or
permitted to be given under this Agreement must be in writing and will
have been deemed to have been properly given, unless explicitly stated
otherwise, if sent by (i) Federal Express or other comparable overnight courier,
(ii) registered or certified mail, postage prepaid, return receipt requested,
(iii) telecopy with confirmation during normal business hours to the place of
business of the recipient, or (iv) personal delivery with a signed receipt. For
purposes of all notices, the addresses and telecopy numbers of the parties are
set forth on the signature page of this Agreement and in the applicable WP
Schedules. All notices, notifications, demands or requests so given will be
deemed given and received (A) if mailed, seven (7) days after being deposited in
the mail, (B) if sent via overnight courier, the next business day after being
deposited, (C) if telecopied, the next business day after being telecopied, and
(D) if personally delivered, when delivered.

     10.2 CHOICE OF LAW AND VENUE. THIS AGREEMENT AND THE APPLICATION OR
INTERPRETATION HEREOF, WILL BE GOVERNED EXCLUSIVELY BY THE LAWS OF THE STATE OF
CALIFORNIA WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF LAWS. VENUE FOR
ANY ACTION RELATING TO THIS AGREEMENT WILL BE MAINTAINED IN SAN FRANCISCO
COUNTY, CALIFORNIA.

     10.3 HEADINGS AND SECTIONS. The headings in this Agreement are inserted
for convenience only and do not describe, interpret, define or limit the scope,
extent or intent of this

                                  Confidential
                                  Page 19 of 21


<PAGE>   20




Agreement or any provision hereof. Unless the context requires otherwise, all
references in this Agreement to Sections will be deemed to mean and refer to
Sections of this Agreement.

     10.4 INDEPENDENT PARTIES. Nothing contained herein will be deemed to
create or construed as creating a joint venture or partnership between Schwab
and Aether. Schwab is not, by virtue of this Agreement or otherwise, authorized
as an agent or legal representative of Aether. Schwab is not granted any right
or authority to assume or to create any obligation or responsibility, express or
implied, on behalf of or in the name of Aether or to bind either in any manner.
Further, it is not the intention of this Agreement or of the parties hereto to
confer a third party beneficiary right of action upon any third party or entity
whatsoever, and nothing hereinbefore or hereinafter set forth will be construed
so as to confer upon any third party or entity other than the parties hereto a
right of action under this Agreement or in any manner whatsoever.

     10.5 AMENDMENTS AND ORDER OF PRECEDENCE. Notwithstanding anything else
contained in this Agreement, this Agreement may be amended, supplemented or
restated only with the written consent of both parties. In the event of any
conflict or inconsistency between this Agreement and any WP Schedule, the WP
Schedule will control, but only with respect to the products and services
covered by such WP Schedule.

     10.6 NUMBER AND GENDER. Where the context so indicates, the masculine
includes the feminine and the neuter, the neuter includes the masculine and
feminine, and the singular includes the plural.

     10.7 COUNTERPARTS. This Agreement may be executed in multiple counterparts,
each of which is considered an original and will be binding upon the party who
executed the same, but all of such counterparts will constitute the same
agreement.

     10.8 ARBITRATION. Any controversy with respect to this Agreement or Aether,
whether arising before or after this Agreement, between or among any party will
be resolved by arbitration. Any arbitration under this Agreement will be
conducted in accordance with the rules, then applying, of the American
Arbitration Association. The award of the arbitrators will be final and binding
on the parties, and judgment upon the award rendered may be entered in any
court, state or federal, having jurisdiction. This agreement to arbitrate does
not entitle any party to arbitrate claims that would be barred by the applicable
statute of limitations if such claims were brought in a court of competent
jurisdiction. If at the time a demand for arbitration is made, the claims sought
to be arbitrated would have been barred by the relevant statute of limitations
or other time bar, any party may assert the limitations as a bar to the
arbitration by applying to any court of competent jurisdiction. The failure to
assert such bar by application to a court, however, will not preclude its
assertion before the arbitrators.

     10.9 COOPERATION. Each party agrees, to the extent called upon by the
other, to cooperate with such party with regard to matters relating to
regulatory and compliance matters and threatened or pending litigation or
arbitration against that party with regard to activities conducted under this
Agreement.

                                  Confidential
                                  Page 20 of 21


<PAGE>   21



     10.10 SEVERABILITY. If any provision of this Agreement is held to be
illegal, invalid or unenforceable under present or future laws effective during
the term hereof, the legality, validity and enforceability of the remaining
provisions of this Agreement will not be affected thereby, and in lieu of such
illegal, invalid or unenforceable provision, there will be added automatically
as a part of this Agreement a provision as similar in terms to such illegal,
invalid or unenforceable provision as may be legal, valid and enforceable.

     10.11 ENTIRE AGREEMENT. This Agreement and its exhibits (i) constitute the
entire agreement between the parties relating to the subject matter hereof, and
(ii) supersede all previous contracts and agreements between the parties hereto,
both oral and written.

     10.12 AUTHORSHIP. This Agreement will not be construed in favor or against
either party by reason of the authorship of any provisions hereof.

     10.13 FORCE MAJEURE. If either party cannot perform any of its obligations
because of any act of God, accident, strike, court order, fire, riot, war, or
any other cause not within the party's control ("FORCE MAJEURE"), then the
non-performing party shall: (i) immediately notify the other party; (ii) take
reasonable steps to resume performance as soon as possible; and (iii) not be
considered in breach during the duration of the Force Majeure event. In the
event, a Force Majeure event continues for a period of ten (10) business days,
Schwab may terminate this Agreement by providing written notice to Aether to
that effect. Such a termination shall be considered "for cause." In no event
shall Force Majeure include breach of any Year 2000 obligation or warranty in
this Agreement, or of failures of hardware or software of Aether.

     10.14 ASSIGNMENT. Neither party may assign its rights or delegate its
obligations hereunder without the express written consent of the other party,
which consent may not be unreasonably withheld, provided, however, that Schwab
may assign this Agreement and all of its rights and obligations hereunder to any
Schwab Affiliate upon 30 days' prior notice to Aether so long as the assignee
agrees to abide by the terms and conditions of this Agreement. In no event may
Aether assign its rights or delegate its obligations hereunder, without Schwab's
prior written consent, which may be withheld in Schwab's reasonable discretion.
This Agreement will be binding upon and inure to the benefit of the parties
hereto and their respective representatives, successors and assigns.

             IN WITNESS WHEREOF, duly authorized representatives of the parties
have executed this Agreement as of the Effective Date:

<TABLE>
<CAPTION>

          CHARLES SCHWAB & CO., INC.                     AETHER SYSTEMS,INC.

 <S>                                       <C>

 /s/ Robert Taylor                          /s/ W. B. Hannon
 ------------------------------------       -----------------------------------
 Signature  BOB TAYLOR                      Signature    W B HANNON
 ------------------------------------       -----------------------------------
 Printed Name VICE PRESIDENT                Printed Name VICE PRESIDENT
 ------------------------------------       -----------------------------------
 Title    12/23/99                          Title     12-23-99
 ------------------------------------       -----------------------------------
 Date                                       Date
</TABLE>


                                  Confidential
                                 Page 21 of 21

<PAGE>   1
                                                                   EXHIBIT 10.25

                                INCISCENT, INC.

                  SERIES A PREFERRED STOCK PURCHASE AGREEMENT

         This Series A Preferred Stock Purchase Agreement (the "Agreement") is
made as of February 8, 2000 by and among Inciscent, Inc., a Delaware
corporation (the "Company"), and the investors listed on Exhibit A attached
hereto (each a "Purchaser" and together the "Purchasers").

         The parties hereby agree as follows:

         1.       PURCHASE AND SALE OF PREFERRED STOCK.

                  1.1      SALE AND ISSUANCE OF SERIES A PREFERRED STOCK.

                           (a)      The Company shall adopt and file with the
Secretary of State of the State of Delaware on or before the Closing (as
defined below) the Amended and Restated Certificate of Incorporation in the
form attached hereto as Exhibit B (the "Restated Certificate").

                           (b)      Subject to the terms and conditions of this
Agreement, each Purchaser agrees to purchase, severally and not jointly, at the
Closing and the Company agrees to sell and issue to each Purchaser at the
Closing that number of shares of the Company's Series A Preferred Stock (the
"Series A Preferred Stock") set forth opposite each such Purchaser's name on
Exhibit A attached hereto, free and clear of any lien, claim, pledge, option,
charge, adverse interest, security interest, purchase option, mortgage, deed of
trust, or other similar right of third parties (each a "Lien"), other than as
contemplated by the Agreements (as defined herein), at a purchase price of
$2.00 per share, payable (as specified on Exhibit A) in cash, by promissory
note and/or in services pursuant to one of the Service Agreements (as defined
below) to be entered into at the Closing. The shares of Series A Preferred
Stock issued to the Purchasers pursuant to this Agreement shall be hereinafter
referred to as the "Securities."

                           (c)      The net cash proceeds from the sale of the
Securities shall be used for general corporate purposes, including working
capital.

                  1.2      CLOSING; DELIVERY.

                           (a)      Subject to the terms and upon satisfaction
or waiver of the conditions set forth herein, the closing of the purchase and
sale of the Securities (the "Closing") shall occur on the fourth business day
after the expiration or termination of the applicable waiting period under the
Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the "HSR
Act"), or such other date as the parties may agree. The "Closing Date" shall be
the date the Closing occurs. The Closing shall take place at the offices of
Wilmer, Cutler & Pickering, 2445 M Street, N.W., Washington, D.C. 20037-1420,
at 10 a.m. on the Closing Date.

                                       1

<PAGE>   2

                           (b)      At the Closing, the Company shall deliver
to each Purchaser a certificate registered in such Purchaser's name
representing the Securities being purchased thereby against payment of the
purchase price therefor (as set forth in Exhibit A) by (i) if applicable to
such Purchaser, check payable to the Company or by wire transfer to the
Company's bank account, (ii) in the case of Aether Systems, Inc. ("Aether"),
delivery of a duly executed promissory note and pledge agreement to the Company
containing terms acceptable to the Company, (iii) in the case of Metrocall,
Inc. ("Metrocall"), subject to Section 4.1(n)(i), the execution and delivery of
the agreement between the Company and Metrocall containing terms acceptable to
the Company and embodying the terms attached hereto as Exhibit C and (iv) in
the case of PSINet Inc. ("PSINet"), (A) execution and delivery of the Virtual
ISP Agreement between Metrocall and PSINet substantially in the form as set
forth in Exhibit B to that certain Common Stock Purchase Agreement between
Metrocall and PSINet dated as of February 2, 2000 (the "PSINet Service
Agreement" and together with the Metrocall Service Agreement and Aether Service
Agreement, each as defined below, the "Service Agreements") and (B) assignment
of Metrocall's rights and obligations under the PSINet Service Agreement to the
Company in accordance with the terms thereof.

                           (c)      At the Closing, the Company and each of the
Purchasers shall execute and deliver each of the agreements, certificates and
other documents contemplated by Section 4.1 to be executed and delivered by
each such party at the Closing.

         2.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company
hereby represents and warrants to each Purchaser that as of the date hereof and
as of the Closing Date (unless another date or period of time is specifically
stated herein for a representation or warranty), except as set forth on a
Schedule of Exceptions attached hereto as Exhibit E, which exceptions shall be
deemed to be representations and warranties as if made hereunder, which
representations and warranties are made giving effect to the transactions
contemplated under the Agreements:

                  2.1      ORGANIZATION, GOOD STANDING AND QUALIFICATION. The
Company is a corporation duly organized, validly existing and in good standing
under the laws of the State of Delaware and has all requisite corporate power
and authority to carry on its business, to enter into and to perform the
Agreements to which it is a party and to carry on the transactions contemplated
by the Agreements to which it is a party. The Company is duly qualified to
transact business and is in good standing in each jurisdiction in which the
failure so to qualify could not reasonably be expected to have a material
adverse effect on its business, assets, conditions or prospects (financial or
otherwise), or operations of the Company (as such are currently conducted and
as such are proposed to be conducted) or the ability of the Company to perform
its obligations under any of the Agreements (as herein defined).

                  2.2      CAPITALIZATION.  The authorized capital of the
Company consists, or will consist, immediately prior to the Closing, solely of:

                           (a)      15,000,000 shares of Preferred Stock, all
of which have been designated Series A Preferred Stock (the "Preferred Stock"),
and none of which are issued and

                                       2

<PAGE>   3

outstanding immediately prior to the Closing. The rights, privileges and
preferences of the Preferred Stock are as stated in the Restated Certificate.

                           (b)      19,500,000 shares of the Company's common
stock, par value $.0001 per share (the "Common Stock"), 3,000,000 shares of
which are issued and outstanding as of the date hereof. The Schedule of
Exceptions contains a true and complete list of the stockholders of the
Company, showing the number of shares of Common Stock or other securities of
the Company held by each stockholder as of the date of this Agreement and as of
the date of the Closing and the consideration paid to the Company, if any,
therefor. All of the outstanding shares of Common Stock have been duly
authorized, fully paid and are nonassessable and have been offered, issued and
sold in compliance with all applicable federal and state securities laws.
Immediately prior to the Closing, all of the issued and outstanding shares of
Common Stock are owned by officers, directors, employees and consultants of the
Company (collectively, the "Founders").

                           (c)      The Company will reserve 1,500,000 shares
of Common Stock for issuance to officers, directors, employees and consultants
of the Company pursuant to its share option plan to be adopted by the Board of
Directors and approved by the Company and its stockholders after the Closing
(the "Share Option Plan"). All of such reserved shares of Common Stock remain
available for issuance to officers, directors, employees and consultants
pursuant to the Share Option Plan. The remaining 15,000,000 shares of Common
Stock are reserved for issuance upon any conversion of the Series A Preferred
Stock.

                           (d)      Except for conversion privileges of the
Preferred Stock, and  except as set forth in the Investors' Rights Agreement
(as defined below), the Voting Agreement (as defined below), the Co-Sale
Agreement (as defined below), and the Founders Agreements and agreements
contemplated therein dated as of February 2, 2000 between the Company and
certain individuals named therein (the "Founders Agreements"), there are (i) no
outstanding options, warrants, rights (including conversion or preemptive
rights and rights of first refusal or similar rights) or agreements, orally or
in writing, for the purchase or acquisition from the Company of any issued or
unissued shares of its capital stock, (ii) no restrictions upon, or agreements
or understandings of the Company or, to the knowledge of the Company,
understandings of any other person, with respect to, the voting, registration,
transfer, sale or other disposition of any shares of capital stock of the
Company and (iii) no outstanding contractual obligations of the Company to
repurchase, redeem or otherwise acquire any shares of capital stock of the
Company.

                  2.3      SUBSIDIARIES. The Company does not currently own or
control, directly or indirectly, any interest in any other corporation,
association, partnership, or other business entity.

                  2.4      AUTHORIZATION. All corporate action on the part of
the Company, its officers, directors and stockholders necessary for the
authorization, execution and delivery of this Agreement, the Investors' Rights
Agreement, in the form attached hereto as Exhibit F (the "Investors' Rights
Agreement"), the Co-Sale Agreement in the form attached hereto as Exhibit G
(the "Co-Sale Agreement"), the Voting Agreement in the form attached hereto as
Exhibit H (the "Voting Agreement"), and the Service Agreements (this Agreement,
the Voting Agreement, the Investors' Rights Agreement, the Co-Sale Agreement
and the Service Agreements are

                                       3

<PAGE>   4


collectively referred to herein as the "Agreements"), the performance of all
obligations of the Company hereunder and thereunder and the authorization,
issuance and delivery of the Securities has been taken prior to the date
hereof, and the Agreements to which the Company is a party, when executed and
delivered by the Company, shall constitute valid and legally binding
obligations of the Company, enforceable against the Company in accordance with
their terms except (i) as limited by applicable bankruptcy, insolvency,
reorganization, moratorium, fraudulent conveyance, and other laws of general
application affecting enforcement of creditors' rights generally, as limited by
laws relating to the availability of specific performance, injunctive relief,
or other equitable remedies, or (ii) to the extent the indemnification
provisions contained in the Investors' Rights Agreement may be limited by
applicable federal or state securities laws.

                  2.5      VALID ISSUANCE OF SECURITIES. The Securities that
are being issued to the Purchasers hereunder, when issued, sold and delivered
in accordance with the terms hereof for the consideration expressed herein,
will be duly and validly issued, fully paid and nonassessable and free of
restrictions on transfer other than restrictions on transfer and any preemptive
rights or Liens, under this Agreement, the Investors' Rights Agreement, the
Co-Sale Agreement and applicable state and federal securities laws. Based in
part upon the representations of the Purchasers in this Agreement and subject
to the provisions of Section 2.6 below, the Securities will be issued in
compliance with all applicable federal and state securities laws. The Common
Stock issuable upon conversion of the Securities has been duly and validly
reserved for issuance, and upon issuance in accordance with the terms of the
Restated Certificate, shall be duly and validly issued, fully paid and
nonassessable and free of restrictions on transfer, preemptive rights and
Liens, other than restrictions on transfer, preemptive rights or Liens imposed
by this Agreement, the Investors' Rights Agreement, the Co-Sale Agreement and
applicable federal and state securities laws, and will be issued in compliance
with all applicable federal and state securities laws.

                  2.6      GOVERNMENTAL CONSENTS. No consent, approval, order
or authorization of, or registration, qualification, designation, declaration
or filing with, any federal, state or local governmental authority on the part
of the Company is required in connection with the execution, delivery and
performance of the Agreements to which the Company is a party, or the offer,
sale or issuance of the Securities, or the consummation of the transactions
contemplated by this Agreement, except for filings pursuant to the HSR Act, if
any.

                  2.7      LITIGATION.

                           (a)      There is no action, suit, proceeding or
investigation pending or, to the Company's knowledge, currently threatened
against the Company, its properties, assets or business, that questions the
validity of the Agreements to which the Company is a party or the right of the
Company to enter into them, or to consummate the transactions contemplated
hereby or thereby, or that, individually or in the aggregate, has had, or could
reasonably be expected to have, a material adverse effect on its business,
assets, conditions or prospects (financial or otherwise), or operations of the
Company (as such are currently conducted and as such are proposed to be
conducted) or the ability of the Company to perform its obligations under any
of the Agreements to which the Company is a party, or any change in the current
equity ownership of the Company, nor is the Company aware that there is any
basis for the foregoing. The Company is not a party or subject to the
provisions of any order, writ, injunction, judgment or

                                       4

<PAGE>   5

decree of any court or government agency or instrumentality. There is no
action, suit, proceeding or investigation by the Company currently pending or
which the Company intends to initiate.

                           (b)      The Company has no knowledge or belief that
there is pending or threatened any claim or litigation against the Company
contesting its right to produce, manufacture, sell or use any product, process,
method, substance, part or other material presently produced, manufactured,
sold or used or planned to be produced, manufactured, sold or used by the
Company in connection with the operations of the Company.

                  2.8      INTELLECTUAL PROPERTY. All of the patents, patent
applications, trademarks, trade names, service marks and registered copyrights
and make work rights and applications therefor owned by or licensed to the
Company and used or held for use in connection with the business proposed to be
conducted by the Company (the "Intellectual Property") have been duly applied
for or registered and filed with or issued by each appropriate governmental
entity in the jurisdiction in which the Company anticipates that it will
conduct its business and all necessary affidavits of continuing use have been
filed and all necessary maintenance fees have been paid to continue all such
rights in effect. The Company owns or is licensed or otherwise has the right to
use, without payment to any other person, except as required pursuant to any
Service Agreement, all Intellectual Property used in or necessary for the
Company's business as proposed to be conducted. The Company's ownership and/or
use of the Intellectual Property in its business as proposed to be conducted
does not conflict with, or result in any violation of, or default (with or
without notice or lapse of time, or both) under, or give rise to a right of
termination, cancellation or acceleration of any obligation or result in any
loss of a material benefit under or the creation of any Lien in or upon any of
the properties or assets of the Company under, any contract between the Company
and any person. The Company has not received any communications alleging that
the Company has violated or, by conducting its business, would violate any of
the patents, trademarks, service marks, tradenames, copyrights, trade secrets
or other proprietary rights or processes of any other person or entity. The
Company is not aware of any infringement or misappropriation by others of any
of its Intellectual Property. The Company is not aware that any of its
employees is obligated under any contract (including licenses, covenants or
commitments of any nature) or other agreement, or subject to any judgment,
decree or order of any court or administrative agency, that would interfere
with the use of such employee's best efforts to promote the interest of the
Company or that would conflict with the Company's business. Neither the
execution, delivery or performance of this Agreement, nor the carrying on of
the Company's business by the employees of the Company, nor the conduct of the
Company's business as proposed, will conflict with or result in a breach of the
terms, conditions, or provisions of, or constitute a default under, any
contract, covenant or instrument under which any such employee is now
obligated. It is not necessary to use any inventions of any of its employees
(or persons it currently intends to hire) made prior to their employment by the
Company. There are no outstanding options, licenses or agreements of any kind
relating to the Intellectual Property, nor is the Company a party to any
options, licenses or agreements of any kind with respect to the patents,
trademarks, service marks, trade names, copyrights, mask-works, trade secrets,
processes, data or know-how of any other person or entity. None of the holders
of Common Stock, whether vested or unvested, owns any rights in patents,
trademarks, service marks, trade names, copyrights, mask-works, trade secrets,
processes, data or know-how

                                       5

<PAGE>   6

directly or indirectly competitive with those owned or to be used by the
Company or derived from or in connection with the conduct of the Company's
business.

                  2.9      COMPLIANCE WITH OTHER INSTRUMENTS.

                           (a)      The Company is not in violation or default
of any provisions of its Restated Certificate or Bylaws or of any instrument or
contract to which it is a party or by which it is bound, or of any provision of
federal or state statute, rule or regulation to which it or its property is
subject. The execution, delivery and performance of the Agreements to which the
Company is a party and the consummation of the transactions contemplated hereby
or thereby will not (i) result in any violation or be in conflict with or
constitute, with or without the passage of time and giving of notice, a default
under (A) the provisions of the Restated Certificate or Bylaws of the Company
or (B) any material document, material agreement or other material instrument
to which the Company is a party or by which the Company is bound ("Company
Third Party Contracts"), (ii) require any third party consent, waiver or
approval in order that any Company Third Party Contract remain in effect
without material modification after the Closing Date and without giving rise to
any right to termination, cancellation, acceleration or loss of any material
right or benefit, or (iii) result in the creation or imposition of any Lien on
the Company's properties pursuant to (A) any law or regulation to which the
Company or any of its assets or property is subject, or (B) any judgment, order
or decree to which the Company is bound or any of its assets or property is
subject. No event has occurred which would, and the execution, delivery and
performance of the Agreements to which the Company is a party and the
consummation of the transactions contemplated hereby or thereby will not, with
the passage of time or the giving of notice, or both, constitute a breach or
violation, in any material respect, under any applicable judgments, orders,
writs, decrees, federal, state and local laws, rules and regulations which,
individually or in the aggregate, has had, or could reasonably be expected to
have, a material adverse effect on its business, assets, conditions or
prospects (financial or otherwise), or operations of the Company (as such are
currently conducted and as such are proposed to be conducted) or the ability of
the Company to perform its obligations under any of the Agreements to which the
Company is a party.

                           (b)      To the best of its knowledge, the Company
has avoided every condition, and has not performed any act, the occurrence of
which would result in the Company's loss of any right granted under any
license, distribution agreement or other agreement.

                  2.10     AGREEMENTS; ACTION.

                           (a)      Except for the Agreements and the Founders
Agreements, there are no agreements, understandings or proposed transactions
between the Company and any of its officers, directors, affiliates, or any
affiliate thereof.

                           (b)      Except for the Agreements, there are no
agreements, understandings,  instruments, contracts or proposed transactions to
which the Company is a party or by which it is bound that involve (i)
obligations (contingent or otherwise) of, or payments to, the Company or any of
its subsidiaries in excess of, $25,000, (ii) the license of any patent,
copyright, trade secret or other proprietary right to or from the Company or
any of its


                                       6

<PAGE>   7

subsidiaries, (iii) the grant of rights to manufacture, produce, assemble,
license, market, or sell its products to any other person or affect the
Company's exclusive right to develop, manufacture, assemble, distribute, market
or sell its products, (iv) any joint venture contract or arrangement or other
agreement involving a sharing of profits or expenses or pursuant to which the
Company has granted rights to manufacture, produce, assemble, license, market
or sell its products to any other person or that affects the Company's
exclusive rights to develop, manufacture, distribute and sell its products, or
(v) agreements limiting the ability of the Company to compete in any line of
business or in any geographic area or with any person.

                           (c)      The Company has not (i) declared or paid
any dividends, or authorized or made any distribution upon or with respect to
any class or series of its capital stock, (ii) incurred any indebtedness for
money borrowed or incurred any other liabilities individually in excess of
$25,000 or in excess of $100,000 in the aggregate, (iii) made any loans or
advances to any person, other than ordinary advances for travel expenses, or
(iv) sold, exchanged or otherwise disposed of any of its assets or rights,
other than the sale of its inventory in the ordinary course of business.

                           (d)      The Company has not engaged in any
discussion (i) with any representative of any entity regarding the merger of
the Company with or into any such entity, (ii) with any representative of any
entity or any individual regarding the sale, conveyance or disposition of all
or substantially all of the assets of the Company or a transaction or series of
related transactions in which more than fifty percent (50%) of the voting power
of the Company would be disposed of, or (iii) regarding any other form of
liquidation, dissolution or winding up of the Company.

                  2.11     DISCLOSURE. The Company has fully provided the
Purchasers with all the information that the Purchasers have requested for
deciding whether to acquire the Securities and all information that the Company
believes is reasonably necessary to enable the Purchasers to make such a
decision. No representation or warranty of the Company contained in this
Agreement and the exhibits attached hereto, or any certificate furnished or to
be furnished to Purchasers at the Closing (when read together) contains any
untrue statement of a material fact or omits to state a material fact necessary
in order to make the statements contained herein or therein not misleading in
light of the circumstances under which they were made.

                  2.12     TRANSACTIONS WITH RELATED PARTIES. No employee,
officer, director or stockholder of the Company or member of his or her
immediate family is indebted to the Company, nor is the Company indebted (or
committed to make loans or extend or guarantee credit) to any of them, other
than (i) for payment of salary for services rendered, (ii) for reimbursement
for reasonable expenses incurred on behalf of the Company, (iii) for other
employee benefits made generally available to all employees or (iv) as
specifically contemplated by the Agreements and the Founders Agreements. Except
for their interests in any of the Purchasers, none of such persons has any
direct or indirect ownership interest in any person or entity with which the
Company is affiliated or with which the Company has a business relationship, or
any person or entity that competes with the Company, except that employees,
stockholders, officer or directors of the Company and members of their
immediate families may own stock in publicly traded companies that may compete
with the Company. No officer, director or stockholder or any member of his or
her immediate family is directly or indirectly

                                       7

<PAGE>   8


interested in any material contract with the Company (other than such contracts
as relate to any person's ownership of capital stock or other securities of the
Company). The Company is not a guarantor or indemnitor of any indebtedness of
any other person, firm or corporation.

                  2.13     RIGHTS OF REGISTRATION AND VOTING RIGHTS. Except as
contemplated by the Investors' Rights Agreement, the Company has not granted or
agreed to grant any registration rights, including piggyback rights, to any
person or entity. To the Company's knowledge, except as contemplated by the
Voting Agreement, no stockholder of the Company has entered into any agreements
with respect to the voting of capital shares of the Company.

                  2.14     TITLE TO PROPERTY AND ASSETS. The Company has good
and marketable title to its property and assets free and clear of all Liens,
except such Liens which arise in the ordinary course of business and do not
materially impair the Company's ownership or use of such property or assets.
With respect to the property and assets it leases, the Company is in compliance
with such leases and holds a valid leasehold interest free of any Liens or
claims.

                  2.15     FINANCIAL STATEMENTS. The Company has not prepared
any balance sheet, income statement, statement of operations, statement of
changes in financial position and stockholders' equity or other financial
statement.

                  2.16     ABSENCE OF OPERATIONS AND LIABILITIES. The Company
has conducted no operations prior to the Closing Date other than taking such
actions as are reasonably necessary to incorporate in the State of Delaware, to
complete the corporate organization of the Company and to negotiate the
Agreements. The Company has incurred no material liabilities, whether absolute
or contingent, other than the incurrence of fees and expenses (including
attorney's fees) related to the formation and the negotiation of the
Agreements.

                  2.17     EMPLOYEE BENEFIT PLANS.  The Company does not have
any Employee Benefit Plan as defined in the Employee Retirement Income Security
Act of 1974.

                  2.18     TAX RETURNS AND PAYMENTS. The Company has filed all
tax returns and reports as required by law. These returns and reports are true
and correct in all material respects. The Company has paid all taxes and other
assessments due. The provision for taxes of the Company is adequate for taxes
due or accrued as of the date hereof. The Company has not elected pursuant to
the Internal Revenue Code of 1986, as amended (the "Code"), to be treated as an
S corporation. The Company has never had a tax deficiency or tax audit and the
Company has made all withholdings or collections for all taxes, including,
without limitation, federal and state income taxes, Federal Insurance
Contribution Act taxes and federal and state unemployment tax act taxes, of its
employees. The Company is not and has not been delinquent in the payment of any
tax, assessment or governmental charge. The Company has never had any tax
deficiency proposed or assessed against it and has not executed any waiver of
any statute of limitations on the assessment or collection of any tax or
governmental charge which had a material adverse effect on the financial
condition and business prospect of the Company. The Company has not been
required to, and has not, filed any federal income tax returns nor any state
income or franchise tax returns. Since the date of its incorporation, the
Company has made adequate provisions on its books of account for all taxes,
assessments and governmental charges with respect to its business, properties
and operations for such period.

                                       8

<PAGE>   9

                  2.19     INSURANCE. At Closing, the Company will have in full
force and effect fire and casualty insurance policies, with extended coverage,
sufficient in amount (subject to reasonable deductibles) to allow it to replace
any of its properties that might be damaged or destroyed.

                  2.20     LABOR AGREEMENTS AND ACTIONS. The Company is not
bound by or subject to (and none of its assets or properties is bound by or
subject to) any written or oral, express or implied, contract, commitment or
arrangement with any labor union, and no labor union has requested or, to the
knowledge of the Company, has sought to represent any of the employees,
representatives or agents of the Company. There is no strike or other labor
dispute involving the Company pending, or to the knowledge of the Company
threatened, which could have a material adverse effect on the assets,
properties, financial condition, operating results, or business of the Company,
nor is the Company aware of any labor organization activity involving its
employees. The employment of each officer and employee of the Company is
terminable at the will of the Company. The Company has complied in all material
respects with all applicable state and federal equal employment opportunity
laws and with other laws related to employment.

                  2.22     PERMITS. The Company and each of its subsidiaries
has all franchises, permits, licenses and any similar authority necessary for
the conduct of its business, the lack of which could materially and adversely
affect the business, properties, prospects, or financial condition of the
Company. The Company is not in default in any material respect under any of
such franchises, permits, licenses or other similar authority.

                  2.23     CORPORATE DOCUMENTS. Copies of the Restated
Certificate and Bylaws of the Company have been provided to counsel for the
Purchasers. The copy of the minute books of the Company provided to the
Purchasers' counsel contains minutes of all meetings of directors and
stockholders and all actions by written consent without a meeting by the
directors and stockholders since the date of incorporation and reflects all
actions by the directors (and any committee of directors) and stockholders with
respect to all transactions referred to in such minutes accurately in all
material respects. The copies of the Restated Certificate and Bylaws and the
minute books are true, correct and complete and, with respect to the Restated
Certificate and Bylaws, contain all amendments through the date hereof.

                  2.24     ENVIRONMENTAL AND SAFETY LAWS. The Company is not in
violation of any applicable statute, law or regulation relating to the
environment or occupational health and safety, and to its knowledge, no
material expenditures are or will be required in order to comply with any such
existing statute, law or regulation. No Hazardous Materials (as defined below)
are used or have been used, stored, or disposed of by the Company or, to the
Company's knowledge after reasonable investigation, by any other person or
entity on any property owned, leased or used by the Company. For the purposes
of the preceding sentence, "Hazardous Materials" shall mean (a) materials which
are listed or otherwise defined as "hazardous" or "toxic" under any applicable
local, state, federal and/or foreign laws and regulations that govern the
existence and/or remedy of contamination on property, the protection of the
environment from contamination, the control of hazardous wastes, or other
activities involving hazardous substances, including building materials or (b)
any petroleum products or nuclear materials.

                                       9

<PAGE>   10

                  2.25     REAL PROPERTY HOLDING CORPORATION.  The Company is
not a United States Real Property Holding Corporation within the meaning of
Section 897(c)(2) of the Code.

         3.       REPRESENTATIONS AND WARRANTIES OF THE PURCHASERS. Each
Purchaser, severally and not jointly except to the extent provided in Section
3.4, hereby represents and warrants to the Company that as of the date hereof
and as of the Closing Date (unless another date or period of time is
specifically stated herein for a representation or warranty):

                  3.1      AUTHORIZATION. Such Purchaser has all requisite
power and authority to enter into this Agreement. The Agreements to which such
Purchaser is a party, when executed and delivered by such Purchaser, assuming
the due authorization, execution and delivery hereof by the Company, will
constitute valid and legally binding obligations of such Purchaser, enforceable
in accordance with their terms, except (a) as limited by applicable bankruptcy,
insolvency, reorganization, moratorium, fraudulent conveyance, and any other
laws of general application affecting enforcement of creditors' rights
generally, and as limited by laws relating to the availability of a specific
performance, injunctive relief, or other equitable remedies, or (b) to the
extent the indemnification provisions contained in the Investors' Rights
Agreement may be limited by applicable federal or state securities laws.

                  3.2      PURCHASE ENTIRELY FOR OWN ACCOUNT. This Agreement is
made with such Purchaser in reliance upon such Purchaser's representation to
the Company, which by such Purchaser's execution of this Agreement, such
Purchaser hereby confirms, that the Securities to be acquired by such Purchaser
will be acquired for investment for such Purchaser's own account (or for
accounts over which it exercises investment authority), not as a nominee or
agent, and not with a view to the public resale or distribution of any part
thereof in violation of any securities law, subject, however, to the
disposition of such Purchaser's property being at times within its control, and
that such Purchaser has no present intention of selling, granting any
participation in, or otherwise distributing the same in violation of any
securities laws. By executing this Agreement, such Purchaser further represents
that such Purchaser does not presently have any contract, undertaking,
agreement or arrangement with any person to sell, transfer or grant
participations to such person or to any third person, with respect to any of
the Securities; provided, however, that such Purchaser may before the Closing
transfer or assign its rights and/or obligations under the Agreements to which
it is a party, including, without limitation, its right to purchase the
Securities under this Agreement, to any of its affiliates; provided, further,
however, that any such transfer or assignment shall not relieve such Purchaser
from any obligation it may have to the Company hereunder or thereunder,
including, without limitation, any obligation to provide services to the
Company under the Service Agreement to which such Purchaser is a party in
accordance with the terms thereof.

                  3.3      DISCLOSURE OF INFORMATION. Such Purchaser has had an
opportunity to discuss the Company's business, management, financial affairs
and the terms and conditions of the offering of the Securities with the
Company's management and has had an opportunity to review the Company's
facilities. Such Purchaser understands that such discussions, as well as the
business plan and any other written information delivered by the Company to
such Purchaser, were intended to describe the aspects of the Company's business
which it believes to be material.

                                       10

<PAGE>   11

                  3.4      INTERIM OPERATIONS OF HMTF BRIDGE MC II, LLC. HMTF
Bridge MC II, LLC ("HMTF") has been formed solely for the purpose of engaging
in the transactions contemplated by this Agreement and, except for obligations
or liabilities incurred in connection with its organization and the
transactions, agreements and arrangements contemplated by this Agreement, has
engaged in no other business or activities, has incurred no other obligations
or liabilities and has no material assets. The representations and warranties
in this Section 3.4 are made solely by HMTF and are not made, and shall not be
deemed to have been made, by any other Purchaser.

                  3.5      RESTRICTED SECURITIES. Such Purchaser understands
that the Securities have not been registered under the Securities Act of 1933,
as amended (the "Securities Act"), by reason of a specific exemption from the
registration provisions of the Securities Act, which depends upon, among other
things, the bona fide nature of the investment intent and the accuracy of such
Purchaser's representations as expressed herein. Such Purchaser understands
that the Securities are "restricted securities" under applicable U.S. federal
and state securities laws and that, pursuant to these laws, such Purchaser must
hold the Securities indefinitely unless they are registered with the Securities
and Exchange Commission and qualified by state authorities, or an exemption
from such registration and qualification requirements is available. Such
Purchaser acknowledges that the Company has no obligation to register or
qualify the Securities for resale except as set forth in the Investors' Rights
Agreement. Such Purchaser further acknowledges that if an exemption from
registration or qualification is available, it may be conditioned on various
requirements including, but not limited to, the time and manner of sale, the
holding period for the Securities, and on requirements relating to the Company
which are outside of such Purchaser's control, and which (except as provided in
the Investors' Rights Agreement) the Company is under no obligation and may not
be able to satisfy.

                  3.6      NO PUBLIC MARKET. Such Purchaser understands that no
public market now exists for any of the securities issued by the Company, and
that the Company has made no assurances that a public market will ever exist
for the Securities.

                  3.7      LEGENDS.  Such Purchaser understands that the
Securities and any securities issued in respect of or exchange for the
Securities, may bear one or all of the following legends:

                           (a)      "THE SHARES REPRESENTED BY THIS CERTIFICATE
         HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED
         (THE "SECURITIES ACT") AND HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT
         WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION
         THEREOF IN VIOLATION OF APPLICABLE SECURITIES LAWS. NO SUCH SALE OR
         DISTRIBUTION MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION
         STATEMENT RELATED THERETO OTHER THAN PURSUANT TO AN EXEMPTION FROM THE
         REGISTRATION REQUIREMENTS OF UNDER THE SECURITIES ACT."

                           (b)      Any legend set forth in the other
Agreements to which such Purchaser is a party.

                                       11

<PAGE>   12

                           (c)      Any legend required by the Blue Sky laws of
any state to the extent such laws are applicable to the shares represented by
the certificate so legended.

                  3.8 ACCREDITED INVESTOR. Such Purchaser is (i) an accredited
investor as defined in Rule 501(a) of Regulation D promulgated under the
Securities Act and (ii) is experienced in investing in securities of emerging
growth companies and acknowledges that such Purchaser is able to fend for
itself, can bear the economic risk of its investment and has (either alone or
together with its advisors) such knowledge and experience in financial or
business matters that it is capable of evaluating the merits and risks of the
investment in the Securities.

                  3.9 FOREIGN INVESTORS. If such Purchaser is not a United
States person (as defined by Section 7701(a)(30) of the Internal Revenue Code
of 1986, as amended), such Purchaser hereby represents and warrants that it has
satisfied itself as to the full observance of the laws of its jurisdiction in
connection with any invitation to subscribe for the Securities or any use of
this Agreement, including (i) the legal requirements within its jurisdiction
for the purchase of the Securities, (ii) any foreign exchange restrictions
applicable to such purchase, (iii) any governmental or other consents that may
need to be obtained, and (iv) the income tax and other tax consequences, if
any, that may be relevant to the purchase, holding, redemption, sale, or
transfer of the Securities. Such Purchaser's subscription and payment for and
continued beneficial ownership of the Securities, will not violate any
applicable securities or other laws of such Purchaser's jurisdiction.

         4.       CONDITIONS OF THE PURCHASERS' OBLIGATIONS AT CLOSING.

                  4.1      CONDITIONS. The obligations of each Purchaser to the
Company under this Agreement are subject to the fulfillment, on or before the
Closing, of each of the following conditions, unless otherwise waived (provided
that no condition shall arise for the benefit of a Purchaser whose breach of
this Agreement is the cause of the failure of any such condition to be
fulfilled):

                           (a)      REPRESENTATIONS AND WARRANTIES.  The
representations and warranties of the Company contained in this Agreement (i)
shall have been true and correct when made and (ii) shall be (A) in the case of
representations and warranties that are qualified as to materiality or material
adverse effect, true and correct and (B) in all other cases, true and correct
in all material respects, in the case of clauses (A) and (B), as of the Closing
Date with the same force and effect as though made on and as of the Closing
Date

                           (b)      PERFORMANCE.  The Company shall have
performed and complied with all covenants, agreements, obligations and
conditions contained in this Agreement that are required to be performed or
complied with by it on or before the Closing.

                           (c)      COMPLIANCE CERTIFICATE.  The President of
the Company shall deliver to each of the Purchasers at the Closing a
certificate certifying that the conditions specified in Section 4.1 have been
fulfilled.

                           (d)      AUTHORIZATIONS.  All authorizations,
approvals or permits, if any, of any governmental authority or regulatory body
of the United States or of any state that are

                                       12

<PAGE>   13


required in connection with the lawful issuance and sale of the Securities
pursuant to this Agreement shall be obtained and effective as of the Closing.

                           (e)      OPINION OF COMPANY COUNSEL.  Each of the
Purchasers shall have received from Wilmer, Cutler & Pickering, counsel for the
Company, an opinion dated as of the Closing, addressing the matters set forth
in Sections 2.1 through 2.7, subject to customary assumptions and
qualifications.

                           (f)      BOARD OF DIRECTORS.  As of the Closing, the
Company's Board of Directors shall be comprised of the individuals selected
pursuant to Section 1(a) of the Voting Agreement.

                           (g)      INVESTORS' RIGHTS AGREEMENT.  The Company
and each of the Purchasers shall have executed and delivered the Investors'
Rights Agreement in substantially the form attached as Exhibit F;

                           (h)      CO-SALE AGREEMENT.  The Company, each
Founder and each of the Purchasers, and shall have executed and delivered the
Co-Sale Agreement in substantially the form attached as Exhibit G.

                           (i)      VOTING AGREEMENT.  The Company, each
Founder and each of the Purchasers shall have executed and delivered the Voting
Agreement in substantially the form attached as Exhibit H.

                           (j)      RESTATED CERTIFICATE.  The Company shall
have filed the Restated Certificate with the Secretary of State of Delaware on
or prior to the Closing Date, which shall continue to be in full force and
effect as of the Closing Date.

                           (k)      PROPRIETARY INFORMATION AND INVENTION
ASSIGNMENT AGREEMENT.  The Company and each of its employees shall have entered
into the Company's standard form Proprietary Information and Invention
Assignment Agreement, in substantially the form provided to each of the
Purchasers.

                           (l)      QUALIFICATIONS UNDER STATE SECURITIES LAWS.
All registrations, qualifications, permits and approvals required under
applicable state securities laws shall have been, or will be obtained within
the legally required time period for the lawful execution, delivery and
performance of this Agreement and the authorization of the Restated
Certificate, including without limitation the offer and sale of the Securities.

                           (m)      AUTHORIZATIONS.  All authorizations,
approvals or permits of any governmental authority that are required in
connection with the lawful issuance and sale of the Securities shall have been
duly obtained and shall be effective on and as of the Closing, any applicable
waiting period under HSR shall have expired or been terminated with respect to
all Purchasers (to the extent applicable to each Purchaser), and no action
shall have been instituted by the Department of Justice or the Federal Trade
Commission and not withdrawn or terminated that challenges or seeks to enjoin
the consummation of the transactions contemplated hereby.

                                       13

<PAGE>   14

                           (n)      SERVICE AGREEMENTS.

                                    (i)     The Company and Metrocall shall
have executed and delivered the agreement for the contribution to the Company
by Metrocall of the services described on Exhibit C (the "Metrocall Service
Agreement"); provided, however, that, if the Metrocall Service Agreement has
not been executed and delivered as of the Closing Date, this closing condition
shall be deemed to have been satisfied so long as (A) the Metrocall Service
Agreement, incorporating the terms of Exhibit C, shall be executed and
delivered as promptly as practicable after the Closing Date and (B) until the
Metrocall Service Agreement is executed and delivered, Metrocall shall provide
services to the Company on the terms set forth in Exhibit C.

                                    (ii)    The Company and Aether shall have
executed and delivered the agreement for the performance by Aether of the
services described on Exhibit D (the "Aether Service Agreement"); provided,
however, that, if the Aether Service Agreement has not been executed and
delivered as of the Closing Date, this closing condition shall be deemed to
have been satisfied so long as (A) the Aether Service Agreement, incorporating
the terms of Exhibit D, shall be executed and delivered as promptly as
practicable after the Closing Date and (B) until the Aether Service Agreement
is executed and delivered, Aether shall provide services to the Company on the
terms set forth in Exhibit D.

                                    (iii)   PSINet and Metrocall shall have
executed and delivered the PSINet Service Agreement, and the rights and
obligations of Metrocall under the PSINet Service Agreement shall have been
assigned by Metrocall to the Company in accordance with the terms thereof.

                           (o)      AGREEMENT OF LENDERS.  Bank of America,
N.A. (formerly NationsBank, N.A.) and (if necessary) the other lenders under
that certain Fourth Amended and Restated Loan Agreement with Metrocall (the
"Loan Agreement") shall have agreed in writing that the Company (i) will be
treated as an "Unrestricted Subsidiary" under the Loan Agreement, as such term
is defined in the Loan Agreement and (ii) will not be subject to the
restrictions of Section 7.16 of the Loan Agreement.

                           (p)      CLOSING OF METROCALL EQUITY TRANSACTION.
Contemporaneously with the Closing hereof, the "Closing" (as such term is
defined in each the following agreements respectively) of the following
agreements shall have taken place: (i) that certain Common Stock Purchase
Agreement by and between Metrocall and Aether dated as of February 2, 2000;
(ii) that certain Common Stock Purchase Agreement by and between Metrocall and
PSINet dated as of February 2, 2000; and (iii) that certain Common Stock
Purchase Agreement by and between Metrocall and HMTF Bridge MC I, LLCdated as
of February 2, 2000.

         5.       CONDITIONS OF THE COMPANY'S OBLIGATIONS AT CLOSING. The
obligations of the Company to each Purchaser under this Agreement are subject
to the fulfillment, on or before the Closing, of each of the following
conditions, unless otherwise waived; provided, that no condition shall arise
for the benefit of the Company if Metrocall's breach of this Agreement is the
cause of the failure of any such condition to be fulfilled:

                                       14

<PAGE>   15

                  5.1      REPRESENTATIONS AND WARRANTIES. The representations
and warranties of each Purchaser contained in Section 3 shall be true and
correct on and as of the Closing with the same effect as though such
representations and warranties had been made on and as of the Closing.

                  5.2      PERFORMANCE. All covenants, agreements and
conditions contained in this Agreement to be performed by each Purchaser on or
prior to the Closing shall have been performed or complied with in all material
respects.

                  5.3      QUALIFICATIONS. All authorizations, approvals or
permits, if any, of any governmental authority or regulatory body of the United
States or of any state that are required in connection with the lawful issuance
and sale of the Securities pursuant to this Agreement shall be obtained and
effective as of the Closing.

                  5.4      SERVICE AGREEMENTS

                           (a)      The Company and Metrocall shall have
executed and delivered the Metrocall Service Agreement; provided, however,
that, if the Metrocall Service Agreement has not been executed and delivered as
of the Closing Date, this closing condition shall be deemed to have been
satisfied so long as (A) the Metrocall Service Agreement, incorporating the
terms of Exhibit C, shall be executed and delivered as promptly as practicable
after the Closing Date and (B) until the Metrocall Service Agreement is
executed and delivered, Metrocall shall provide services to the Company on the
terms set forth in Exhibit C.

                           (b)      The Company and Aether shall have executed
and delivered the Aether Service Agreement; provided, however, that, if the
Aether Service Agreement has not been executed and delivered as of the Closing
Date, this closing condition shall be deemed to have been satisfied so long as
(A) the Aether Service Agreement, incorporating the terms of Exhibit D, shall
be executed and delivered as promptly as practicable after the Closing Date and
(B) until the Aether Service Agreement is executed and delivered, Aether shall
provide services to the Company on the terms set forth in Exhibit D.

                           (c)      Metrocall and PSINet each shall have
executed the PSINet Service Agreement, and the rights and obligations of
Metrocall under the PSINet Service Agreement shall have been assigned by
Metrocall to the Company in accordance with the terms thereof.

                  5.5      AUTHORIZATIONS. All authorizations, approvals or
permits of any governmental authority that are required in connection with the
lawful issuance and sale of the Securities shall have been duly obtained and
shall be effective on and as of the Closing, any applicable waiting period
under HSR shall have expired or been terminated with respect to all Purchasers
(to the extent applicable to each Purchaser), and no action shall have been
instituted by the Department of Justice or the Federal Trade Commission and not
withdrawn or terminated that challenges or seeks to enjoin the consummation of
the transactions contemplated hereby.

         6.       COVENANTS OF THE COMPANY. The Company hereby covenants and
agrees with the Purchasers that, so long as any Purchaser owns any shares of
Series A Preferred Stock or Common Stock issued upon conversion of the Series A
Preferred Stock, as follows:

                                       15

<PAGE>   16

                  6.1      PROPRIETARY INFORMATION AGREEMENT. Each person now
or hereafter employed by the Company or any subsidiary with access to
confidential information will enter into the Company's standard form
Proprietary Information and Invention Assignment Agreement.

                  6.2      INDEPENDENT ACCOUNTANTS. As promptly as practicable
after the Closing Date, the Company will retain independent public accountants
of recognized national standing who shall audit the Company's financial
statements at the end of each fiscal year. In the event the services of the
independent public accountants so selected, or any firm of independent public
accountants hereafter employed by the Company, are terminated, the Company will
promptly thereafter engage another firm of public accountants of recognized
national standing.

                  6.3      INSURANCE. The Company shall obtain and maintain
valid policies of insurance with respect to its properties and business of the
kinds and in the amounts not less than are customarily obtained by corporations
engaged in the same business and similarly situated, including, without
limitation, workers compensation insurance and insurance against casualty loss,
public liability, libel, slander, defamation, advertising injury and other
risks.

                  6.4      AGREEMENT  OF LENDERS. The Company will use its
reasonable best efforts to obtain the written consent of Bank of America, N.A.
(formerly NationsBank, N.A.) and (if necessary) the other lenders under the
Loan Agreement that the Company (i) will be treated as an "Unrestricted
Subsidiary" under the Loan Agreement, as such term is defined in the Loan
Agreement and (ii) will not be subject to the restrictions of Section 7.16 of
the Loan Agreement.

                  6.5      TERMINATION OF COVENANTS. The covenants of the
Company set forth in this Section 6 shall terminate in all respects on the date
of the closing of a initial firm commitment underwritten public offering
pursuant to any effective registration statement under the Securities Act,
covering the offer and sale of the Company's Common Stock.

         7.       INDEMNIFICATION.

                           (a)      (i)     The Company shall indemnify and
hold harmless each of the Purchasers and their respective officers, directors,
employees, agents and affiliates (the "Purchaser Indemnified Parties") from and
against any and all losses, liabilities, claims, judgments, awards,
settlements, taxes, costs, fees, expenses (including, without limitation,
attorneys' fees) and disbursements (collectively, "Losses") based upon, arising
from or otherwise in respect of (A) any material inaccuracies in or any
material breach of any representation or warranty of the Company contained in
this Agreement or in any certificate or instrument delivered pursuant to this
Agreement or (B) any material breach of any covenant or agreement of the
Company contained in this Agreement or in any certificate or instrument
delivered pursuant to this Agreement; provided, however, that the Company's
obligation under this Section 7.1(a)(i) shall survive the Closing only for a
period of six months.

                                    (ii)    The Company shall indemnify and
hold harmless each of the Purchaser Indemnified Parties (other than PSINet and
its respective officers, directors, employees, agents and affiliates) from and
against any and all Losses based upon, arising from or otherwise in respect of
any failure of PSINet to contribute services to the Company pursuant to

                                       16

<PAGE>   17


the PSINet Service Agreement, in accordance with the terms and conditions
thereof, that have an aggregate value, determined in accordance with such
agreement, equal to the amount specified to be contributed by PSINet in Exhibit
A in partial payment for the Securities to be purchased by PSINet hereunder.

                                    (iii)    The Company shall indemnify and
hold harmless each of the Purchaser Indemnified Parties (other than Metrocall
and its respective officers, directors, employees, agents and affiliates) from
and against any and all Losses based upon, arising from or otherwise in respect
of any failure of Metrocall to contribute services to the Company pursuant to
the Metrocall Service Agreement, in accordance with the terms and conditions
thereof, that have an aggregate value, determined in accordance with such
agreement, equal to the amount specified to be contributed by Metrocall in
Exhibit A in full payment for the Securities to be purchased by Metrocall
hereunder.

                  (b)      As soon as is reasonably practicable after any
Purchaser Indemnified Party becomes aware of any claim that it has under
Section 7.1(a) of this Agreement that may result in a Loss (a "Liability
Claim"), such Purchaser Indemnified Party shall give notice of such claim (a
"Claims Notice") to the Company; provided, however, that a Liability Claim
arising under Section 7(a)(i) must be asserted in a Claims Notice delivered to
the Company within 180 days after the Closing Date, and a Liability Claim
arising under either Section 7(a)(ii) or Section 7(a)(iii) must be asserted in
a Claims Notice delivered to the Company within three years after the Closing
Date. Liability Claims not asserted within the foregoing periods shall be
forever barred.

                  (c)      The Company may elect to defend, at its own expense
and by its own counsel, which counsel must be reasonably satisfactory to the
Purchaser Indemnified Party, any third party Liability Claim by giving notice
to such effect to such Purchaser Indemnified Party within ten days of the
receipt of the applicable Claims Notice. Notwithstanding the foregoing, the
Company may not settle or compromise any proceeding in respect of such
Liability Claim without the prior written consent of such Purchaser Indemnified
Party. If the Company declines to accept the defense of any such Liability
Claim, the Purchaser Indemnified Party may do so at the expense of the Company.
If the Company elects to defend such Liability Claim, the Indemnified Party has
the right to participate, at its own expense, in the defense of such Liability
Claim. The Purchaser Indemnified Party shall cooperate with the Company in
defending and disposing of any third party Liability Claim. Notwithstanding the
foregoing, the Purchaser Indemnified Party has the right to employ counsel
separate from counsel employed by the Company in any such action and to
participate therein at the Company's expense if the Purchaser Indemnified Party
has been advised by counsel reasonably satisfactory to the Company that
representation of the Purchaser Indemnified Party by the Company's counsel
would present a conflict of interest for the Company's counsel.

         8.       MISCELLANEOUS.

                  8.1      SURVIVAL OF REPRESENTATIONS, WARRANTIES AND
COVENANTS. Unless otherwise set forth in this Agreement, the warranties and
representations of the Company and the Purchasers contained in or made pursuant
to this Agreement shall survive the execution and delivery of this Agreement
and the Closing for a period of 180 days following the Closing. The

                                       17

<PAGE>   18

covenants of the Company set forth in Section 6 will survive until terminated
in accordance with Section 6.5.

                  8.2      TRANSFER; SUCCESSORS AND ASSIGNS. The terms and
conditions of this Agreement shall inure to the benefit of and be binding upon
the respective successors and assigns of the parties; provided, however, that
the Company may not assign its rights or obligations under this Agreement
without the approval of a majority of the outstanding shares of Series A
Preferred Stock. Nothing in this Agreement, express or implied, is intended to
confer upon any party other than the parties hereto or their respective
successors and assigns any rights, remedies, obligations, or liabilities under
or by reason of this Agreement, except as expressly provided in this Agreement.

                  8.3      GOVERNING LAW. This Agreement and all acts and
transactions pursuant hereto and the rights and obligations of the parties
hereto shall be governed, construed and interpreted in accordance with the laws
of the State of Delaware, without giving effect to principles of conflicts of
law.

                  8.4      COUNTERPARTS. This Agreement may be executed in two
or more counterparts, each of which shall be deemed an original and all of
which together shall constitute one instrument.

                  8.5      TITLES AND SUBTITLES. The titles and subtitles used
in this Agreement are used for convenience only and are not to be considered in
construing or interpreting this Agreement.

                  8.6      NOTICES. Any notice required or permitted by this
Agreement shall be in writing and shall be deemed sufficient upon delivery,
when delivered personally or by overnight courier or sent by telegram or fax,
or forty-eight (48) hours after being deposited in the U.S. mail, as certified
or registered mail, with postage prepaid, addressed to the party to be notified
at such party's address as set forth on Exhibit A hereto, or as subsequently
modified by written notice.

                  8.7      FINDER'S FEE. Each party represents that it neither
is nor will be obligated for any finder's fee or commission in connection with
this transaction. Each Purchaser agrees to indemnify and to hold harmless the
Company and each other Purchaser from any liability for any commission or
compensation in the nature of a finder's fee (and the costs and expenses of
defending against such liability or asserted liability) for which such
Purchaser or any of its officers, employees, or representatives is responsible.
The Company agrees to indemnify and hold harmless each Purchaser from any
liability for any commission or compensation in the nature of a finder's fee
(and the costs and expenses of defending against such liability or asserted
liability) for which the Company or any of its officers, employees or
representatives is responsible.

                  8.8      FEES AND EXPENSES. Each party shall bear its own
fees and expenses incurred with respect to this Agreement, the documents
referred to herein and the transactions contemplated hereby and thereby.

                                       18

<PAGE>   19

                  8.9      ATTORNEY'S FEES. If any action at law or in equity
(including arbitration) is necessary to enforce or interpret the terms of any
of the Agreements, the prevailing party shall be entitled to reasonable
attorney's fees, costs and necessary disbursements in addition to any other
relief to which such party may be entitled.

                  8.10     AMENDMENTS AND WAIVERS. Any term of this Agreement
may be amended or waived only with the written consent of the Company and the
holders of at least a majority of the outstanding shares of Series A Preferred
Stock; provided, however, that any such amendment or waiver cannot be effected
in accordance with this Section 8.10 if it adversely affects the rights of any
Purchaser (or their respective successors or assigns) hereunder or increases
the obligations of any Purchaser (or their respective successors or assigns)
hereunder unless the affected party expressly consents, in writing, to such
amendment or waiver. Any amendment or waiver effected in accordance with this
Section 8.10 shall be binding upon each of the Purchasers and each transferee
of Securities, each future holder of all such Securities, and the Company.

                  8.11     SEVERABILITY. Any provision of this Agreement which
is invalid or unenforceable shall be ineffective to the extent of such
invalidity or unenforceability, provided that such invalidity or
unenforceability does not deny any party the material benefits of the
transactions for which it has bargained and such invalidity or unenforceability
shall not affect in any way the remaining provisions hereof.

                  8.12     DELAYS OR OMISSIONS. No delay or omission to
exercise any right, power or remedy accruing to any party under this Agreement,
upon any breach or default of any other party under this Agreement, shall
impair any such right, power or remedy of such non-breaching or non-defaulting
party nor shall it be construed to be a waiver of any such breach or default,
or an acquiescence therein, or of or in any similar breach or default
thereafter occurring; nor shall any waiver of any single breach or default be
deemed a waiver of any other breach or default theretofore or thereafter
occurring. Any waiver, permit, consent or approval of any kind or character on
the part of any party of any breach or default under this Agreement, or any
waiver on the part of any party of any provisions or conditions of this
Agreement, must be in writing and shall be effective only to the extent
specifically set forth in such writing. All remedies, either under this
Agreement or by law or otherwise afforded to any party, shall be cumulative and
not alternative.

                  8.13     ENTIRE AGREEMENT. This Agreement and the documents
referred to herein constitute the entire agreement among the parties hereto
pertaining to the subject matter hereof, and any and all other written or oral
agreements relating to the subject matter hereof existing among the parties
hereto are expressly canceled.

                  8.14     CONFIDENTIALITY. Each party hereto agrees that,
except with the prior written permission of the other party, it shall at all
times keep confidential and not divulge, furnish or make accessible to anyone
any confidential information, knowledge or data concerning or relating to the
business or financial affairs of the other parties to which such party has been
or shall become privy by reason of this Agreement, discussions or negotiations
relating to this Agreement, the performance of its obligations hereunder or the
ownership of Securities purchased hereunder; provided however, that this
Section 8.14 shall not apply to (a) any

                                       19

<PAGE>   20


information that becomes generally available to the public without breach on
the part of such party and (b) any information that a party hereto has been
advised by counsel that it is required to disclose pursuant to a subpoena or
the requirements of any applicable law or the rules of any securities exchange.
The provisions of this Section 8.14 shall be in addition to, and not in
substitution for, the provisions of any separate nondisclosure agreement
executed by the parties hereto with respect to the transactions contemplated
hereby.

                  8.15     NO PURCHASER AFFILIATE LIABILITY. Each of the
following is herein referred to as a "Purchaser Affiliate:" (a) any direct or
indirect holder of any equity interests or securities of any Purchaser (whether
such holder is a limited or general partner, member, stockholder or otherwise),
(b) any affiliate of any Purchaser, or (c) any director, officer, employee,
representative or agent of (i) any Purchaser, (ii) any affiliate of any
Purchaser or (iii) any such holder of equity interests or securities referred
to in clause (a) above. No Purchaser Affiliate shall have any liability or
obligation of any nature whatsoever in connection with or under this Agreement
or any of the other documents contemplated hereby or referred to herein or the
transactions contemplated hereby or thereby (whether or not such Purchaser
Affiliate has called or received capital for contribution to such Purchaser),
and the Company hereby waives and releases all claims related to any such
liability or obligation.

                  8.16     WAIVER OF CONFLICTS. Each party to this Agreement
acknowledges that Wilmer, Cutler & Pickering, counsel for the Company and
Metrocall, has in the past performed and may continue to perform legal services
for certain of the Purchasers in matters unrelated to the transactions
described in this Agreement. Accordingly, each party to this Agreement hereby
(a) acknowledges that they have had an opportunity to ask for information
relevant to this disclosure; and (b) gives its informed consent to Wilmer,
Cutler & Pickering's representation of certain of the Purchasers in such
unrelated matters and to Wilmer, Cutler & Pickering's representation of the
Company and Metrocall in connection with this Agreement and the transactions
contemplated hereby.

                  8.17     ANTITRUST LAWS. The parties hereto (to the extent
required of such party under the HSR Act) will file as soon as practicable all
filings that are required under the HSR Act, if any, respond as soon as
practicable to all inquiries received from the Federal Trade Commission or the
Antitrust Division of the Department of Justice for additional information or
documentation and respond as soon as practicable to all inquiries received from
any other government agency.

                  8.18     TERMINATION AND DEFAULT.

                           (a)      General. This Agreement may be terminated
and the transactions contemplated hereby may be abandoned at any time prior to
the Closing Date, as set forth below:

                                    (i)      Mutual Consent. This Agreement may
be terminated by the mutual consent of all parties.

                                    (ii)     Order or Decree. This Agreement
may be terminated by any Purchaser or the Company if any court of competent
jurisdiction in the United States or other U.S. governmental body shall have
issued an order, decree, ruling or taken any other action

                                       20

<PAGE>   21

restraining, enjoining or otherwise prohibiting in any material respects the
transactions contemplated hereby and such order, decree, ruling or other action
shall have become final and nonappealable.

                                    (iii)    Outside Date. This Agreement may
be terminated by either party, (a) if the Closing shall not have occurred by
July 1, 2000 (the "Outside Date") or (b) if one or more condition to such
party's obligation to consummate the transactions contemplated hereby cannot be
satisfied by the Outside Date; provided, however, that no party may exercise
its rights under this Section 8.18(a)(iii) if such party is in material breach
or default under this Agreement.

                                    (iv)     Material Adverse Effect. This
Agreement may be terminated by any Purchaser as to itself if any event has
occurred that, individually or in the aggregate, has had, or could reasonably
be expected to have, a material adverse effect on its business, assets,
conditions or prospects (financial or otherwise), or operations of the Company
(as such are currently conducted and as such are proposed to be conducted) or
the ability of the Company to perform its obligations under any of the
Agreements.

                           (b)      Procedure Upon Termination.  In the event
of the termination of this Agreement, written notice thereof shall promptly be
given to the other parties hereto and this Agreement shall terminate, all
further obligations of the parties hereunder to satisfy the conditions
precedent to the Closing shall terminate, and the transactions contemplated
hereby shall be abandoned without further action by any of the parties hereto.

                  8.19     METROCALL EMPLOYEES. The parties hereto acknowledge
that certain employees of the Company may also having ongoing obligations to
perform services for Metrocall. Such employees will devote to the Company such
portion of their business time as may be necessary to conduct the business of
the Company as proposed to be conducted. In addition, the Company further
agrees that it shall not directly or indirectly solicit for employment, attempt
to employ or employ, or assist any entity in employing or soliciting for
employment any employee or executive who is, at such time, employed by
Metrocall, any other Purchaser or any of their respective affiliates (excluding
the Company).

                  8.20     FURTHER ASSURANCES.

                           (a)      Each of the parties hereto agrees to use
all its reasonable efforts (subject to Section 8.20(b)) to take, or cause to be
taken, all action and to do, or cause to be done, all things necessary, proper
or reasonably advisable to (i) fulfill all conditions referred to in Sections 4
and 5, and (ii) consummate and make effective the transactions contemplated by
this Agreement as soon as practicable.

                           (b)      No party hereto shall intentionally perform
any act that, if performed, or omit to perform any act that, if omitted to be
performed, would prevent or excuse the performance of this Agreement by any
party hereto or that would result in any representation or warranty herein
contained of such party being untrue.

                                       21

<PAGE>   22

                  8.21     PUBLIC ANNOUNCEMENTS. None of the parties hereto or
their respective affiliates shall make publicly available any press release,
publicity materials or other public statement naming or otherwise identifying
any of the other parties hereto or any of their respective affiliates without
such other parties' prior consent, unless (and only to the extent that) the
disclosing party or its affiliate is required to do so under law, or as may be
necessary in connection with licensing and regulatory requirements, obtaining
consents, fulfilling notice requirements, and advising appropriate regulatory
authorities, and then, in any event, such party or its affiliate will use
reasonable efforts to consult with each other applicable party before issuing
such press release or other public disclosure; provided, however, that nothing
in this Section 8.21 shall require any party to obtain the consent of any
Purchaser to disclose the identity of the shareholders of the Company. Each of
the parties hereto shall provide the other parties, as early as reasonably
practicable, drafts of all press releases, publicity materials or other public
statements that include references to any of such other parties or any of their
respective affiliates.

                            [Signature Pages Follow]

                                       22

<PAGE>   23


         The parties have executed this Series A Preferred Stock Purchase
Agreement as of the date first written above.

INCISCENT, INC.

By:
   ----------------------------------------
Name:
     --------------------------------------
         (print)
Title:
      -------------------------------------

PURCHASERS:


METROCALL, INC.                                      AETHER SYSTEMS, INC.

By:                                                  By:
   ---------------------------                          ------------------------
Name:                                                Name:
     -------------------------                            ----------------------
Title:                                               Title:
      ------------------------                             ---------------------


PSINET INC.                                          HMTF BRIDGE MC II, LLC

By:                                                  By:
   ---------------------------                           -----------------------
Name:                                                Name:
      ------------------------                             ---------------------
Title:                                               Title:
      ------------------------                             ---------------------

DB CAPITAL INVESTORS, L.P.                           ROBERT H. LESSIN
BY: DB CAPITAL PARTNERS, L.P.,                       VENTURE CAPITAL LLC
   ITS GENERAL PARTNER

BY: DB CAPITAL PARTNERS, INC.

By:                                                  By:
   ---------------------------                           -----------------------
Name:                                                Name:
      ------------------------                             ---------------------
Title:                                               Title:
      ------------------------                             ---------------------

        [SIGNATURE PAGE FOR SERIES A PREFERRED STOCK PURCHASE AGREEMENT]




<PAGE>   24


                                                                      EXHIBIT F

                                 INCISCENT, INC.

                           INVESTORS' RIGHTS AGREEMENT

     This Investors' Rights Agreement (the "Agreement") is made as of the ___
day of _____________, 2000, by and among Inciscent, Inc. a Delaware corporation
(the "Company"), the investors listed on Exhibit A hereto, each of which is
herein referred to as an "Investor" and collectively the "Investors."

                                    RECITALS

     The Company and the Investors have entered into a Series A Preferred Stock
Purchase Agreement (the "Purchase Agreement") dated as of February 8, 2000
pursuant to which the Company has agreed to sell to the Investors and the
Investors have agreed to purchase from the Company shares of the Company's
Series A Preferred Stock. A condition to the Investors' obligations under the
Purchase Agreement is that the Company and the Investors enter into this
Agreement in order to provide the Investors with (i) certain rights to register
shares of the Company's Common Stock issuable upon conversion of the Series A
Preferred Stock held by the Investors, (ii) certain rights to receive or inspect
information pertaining to the Company, and (iii) a right of first offer with
respect to certain issuances by the Company of its securities. The Company
desires to induce the Investors to purchase shares of Series A Preferred Stock
pursuant to the Purchase Agreement by agreeing to the terms and conditions set
forth herein.

                                    AGREEMENT

     The parties hereby agree as follows:

     1.   REGISTRATION RIGHTS. The Company and the Investors covenant and agree
as follows:

          1.1  DEFINITIONS. For purposes of this Section 1:

               (a)  The terms "register," "registered," and "registration" refer
to a registration effected by preparing and filing a registration statement or
similar document in compliance with the Securities Act of 1933, as amended (the
"Securities Act"), and the declaration or ordering of effectiveness of such
registration statement or document;

               (b)  The term "Registrable Securities" means (i) the shares of
the Company's common stock, par value $0.0001 per share (the "Common Stock"),
issuable or issued upon conversion of the Series A Preferred Stock , (ii) any
other shares of Common Stock of the Company issued as (or issuable upon the
conversion or exercise of any warrant, right or other security which is issued
as) a dividend or other distribution with respect to, or in exchange for or in
replacement of, the shares described in clause, (iii) shares of Common Stock or
Series A Preferred Stock purchased by an Investor pursuant to any exercise of
the right of first offer pursuant to Section 2.2 or (iv) shares of Common Stock
or Series A Preferred Stock purchased



                                       1
<PAGE>   25

by an Investor pursuant to any exercise of the right of first refusal pursuant
to Section 1 of that certain Co-Sale Agreement of even date herewith by and
among the Company, the Investors and certain other parties named therein; (i);
provided, however, that the foregoing definition shall exclude in all cases any
Registrable Securities sold by a person in a transaction in which his or her
rights under this Agreement are not assigned in respect of the Registrable
Securities so sold. Notwithstanding the foregoing, Common Stock or other
securities shall only be treated as Registrable Securities if and so long as
they have not been (A) sold to or through a broker or dealer or underwriter in a
public distribution or a public securities transaction, or (B) sold in a
transaction exempt from the registration and prospectus delivery requirements of
the Securities Act under Section 4(1) thereof so that all transfer restrictions,
and restrictive legends with respect thereto, if any, are removed upon the
consummation of such sale;

               (c)  The number of shares of "Registrable Securities then
outstanding" shall be determined by the number of shares of Common Stock
outstanding which are, and the number of shares of Common Stock issuable
pursuant to then exercisable or convertible securities which are, Registrable
Securities;

               (d)  The term "Holder" means any person owning or having the
right to acquire Registrable Securities or any assignee thereof in accordance
with Section 1.12 of this Agreement;

               (e)  The term "Form S-3" means such form under the Securities Act
as in effect on the date hereof or any successor form under the Securities Act
that permits significant incorporation by reference of the Company's subsequent
public filings under the Securities Exchange Act of 1934, as amended (the
"Exchange Act");

               (f)  The term "SEC" means the Securities and Exchange Commission;
and

               (g)  The term "Qualified IPO" means a firm commitment
underwritten public offering by the Company of shares of its Common Stock
pursuant to a registration statement under the Securities Act that results in
aggregate gross proceeds to the Company of at least $20,000,000.

               (h)  The term "Qualifying Request" means, as of any date, a
written request from the Holders of at least thirty percent (30%) of the
Registrable Securities then outstanding that the Company file a registration
statement under the Securities Act covering the registration of Registrable
Securities whose aggregate offering price is projected to be at least
$20,000,000.

               (i)  The term "Qualifying Small Holder Request" means, as of any
date, a written request from Small Holders that hold, individually or in the
aggregate, at least eight percent (8%) of the Registrable Securities then
outstanding that the Company file a registration statement under the Securities
Act covering the registration of Registrable Securities whose aggregate offering
price is projected to be at least $20,000,000.



                                       2
<PAGE>   26

               (j)  The term "Small Holder" means a Holder that is PSINet Inc.,
HMTF Bridge MC II, LLC, DB Capital Investors, L.P., Robert H. Lessin Venture
Capital LLC, or the direct or indirect transferee of any of them.

               (k)  The term "Small Holder Registration" means a registration of
Registrable Securities pursuant to Section 1.2 in response to a Qualifying Small
Holder Request.

          1.2  REQUEST FOR REGISTRATION.

               (a)  If the Company shall receive at any time after the earlier
of (i) the third anniversary of this Agreement, or (ii) six (6) months after the
effective date of the first registration statement for a public offering of
securities of the Company (other than a registration statement relating either
to the sale of securities to employees of the Company pursuant to a stock
option, stock purchase or similar plan or an SEC Rule 145 transaction), either a
Qualifying Request or a Qualifying Small Holder Request, the Company shall,
within ten days of the receipt thereof, give written notice of such request to
all Holders and shall, subject to the limitations of Section 1.2(b) and of the
next sentence of this Section 1.2(a), use its best efforts to effect as soon as
practicable, and in any event within 60 days of the receipt of such request, the
registration under the Securities Act of all Registrable Securities which the
Holders request to be registered within 20 days of the mailing of such notice by
the Company in accordance with Section 3.4. Notwithstanding the foregoing, only
Registrable Securities held by Small Holders shall be included in a Small Holder
Registration.

               (b)  Notwithstanding the foregoing, if the Company shall furnish
to Holders requesting a registration statement pursuant to this Section 1.2, a
certificate signed by the President of the Company stating that in the good
faith judgment of the Board of Directors of the Company (the "Board"), it would
be seriously detrimental to the Company and its stockholders for such
registration statement to be filed and it is therefore essential to defer the
filing of such registration statement, the Company shall have the right to defer
such filing for a period of not more than 90 days after receipt of the request
of the Holders initiating the registration request (the "Initiating Holders");
provided, however, that the Company may not utilize this right more than once in
any twelve-month period.

               (c)  In addition, the Company shall not be obligated to effect,
or to take any action to effect, any registration pursuant to this Section 1.2:

                    (i)  In response to a Qualifying Small Holder Request, after
the Company has effected one Small Holder Registration pursuant to this Section
1.2 and such Small Holder Registration has been declared or ordered effective
and remained effective long enough for all Registrable Securities registered
thereunder to be sold or until the period set forth in Section 1.5(a) expires;

                    (ii) In response to a Qualifying Request, after the Company
has effected two registrations that are not Small Holder Registrations pursuant
to this Section 1.2 and such registrations have been declared or ordered
effective and remained effective long enough



                                       3
<PAGE>   27

for all Registrable Securities registered thereunder to be sold or until the
period set forth in Section 1.5(a) expires;

                    (iii) If the Company delivers written notice to the
Initiating Holders within 30 days following such Holders' request for
registration that it intends to file a registration statement for the initial
public offering of securities of the Company, provided that such securities are
being issued for the Company's own account (other than a registration statement
relating either to the sale of securities to employees of the Company pursuant
to a stock option, stock purchase or similar plan or an SEC Rule 145
transaction), within 90 days following the Company's notice;

                    (iv)  During the period starting with the date 30 days prior
to the Company's good faith estimate of the date of filing of, and ending on a
date 180 days after the effective date of, a registration subject to Section 1.3
hereof; which relates solely to shares to be offered by the Company; provided
that the Company is actively employing in good faith all reasonable efforts to
cause such registration statement to become effective; or

                    (v)   If the Initiating Holders propose to dispose of shares
of Registrable Securities that may be immediately registered on Form S-3
pursuant to a request made pursuant to Section 1.4 below; provided that such
registration shall not be counted as one of the requested registrations under
Section 1.2.

          1.3  COMPANY REGISTRATION. If (but without any obligation to do so)
the Company proposes to register (including without limitation for this purpose
a registration effected by the Company for stockholders other than the Holders)
any of its stock under the Securities Act in connection with the public offering
of such securities solely for cash (other than a registration relating solely to
the sale of securities to participants in a Company stock plan or a transaction
covered by Rule 145 under the Securities Act, a registration in which the only
stock being registered is Common Stock issuable upon conversion of debt
securities which are also being registered, or any registration on any form
which does not include substantially the same information as would be required
to be included in a registration statement covering the sale of the Registrable
Securities), the Company shall, at such time, promptly give each Holder written
notice of such registration. Upon the written request of each Holder given
within 20 days after mailing of such notice by the Company in accordance with
Section 3.4, the Company shall, subject to the provisions of Section 1.8, cause
to be registered under the Securities Act all of the Registrable Securities that
each such Holder has requested to be registered. The number of times a Holder
may register Registrable Securities under this Section 1.3 shall be unlimited.

          1.4  FORM S-3 REGISTRATION. After consummation of its initial public
offering of its Common Stock, the Company shall use its best efforts to qualify
for registration on Form S-3. In case the Company shall receive from any Holder
or Holders of Registrable Securities then outstanding a written request or
requests that the Company effect a registration on Form S-3 and any related
qualification or compliance with respect to all or a part of the Registrable
Securities owned by such Holder or Holders, the Company will:

               (a)  promptly give written notice of the proposed registration,
and any related qualification or compliance, to all other Holders; and



                                       4
<PAGE>   28

               (b)  as soon as practicable, effect such registration and all
such qualifications and compliance as may be so requested and as would permit or
facilitate the sale and distribution of all or such portion of such Holder's or
Holders' Registrable Securities as are specified in such request, together with
all or such portion of the Registrable Securities of any other Holder or Holders
joining in such request as are specified in a written request given within 15
days after receipt of such written notice from the Company; provided, however,
that the Company shall not be obligated to effect any such registration,
qualification or compliance, pursuant to this Section 1.4: (i) if Form S-3 is
not available for such offering by the Holders; (ii) if the Holders, together
with the holders of any other securities of the Company entitled to inclusion in
such registration, propose to sell Registrable Securities and such other
securities (if any) at an aggregate offering price to the public of less than
$5,000,000; (iii) if the Company shall furnish to the Holders a certificate
signed by the President of the Company stating that in the good faith judgment
of the Board of Directors of the Company, it would be seriously detrimental to
the Company and its stockholders for such Form S-3 Registration to be effected
at such time, in which event the Company shall have the right to defer the
filing of the Form S-3 registration statement for a period of not more than 90
days after receipt of the request of the Holder or Holders under this Section
1.4; provided, however, that the Company shall not utilize this right more than
once in any twelve-month period; (iv) if the Company has, within the
twelve-month period preceding the date of such request, already effected two
registrations on Form S-3 for the Holders pursuant to this Section 1.4; (v) in
any particular jurisdiction in which the Company would be required to qualify to
do business or to execute a general consent to service of process in effecting
such registration, qualification or compliance; or (vi) during the period ending
180 days after the effective date of a registration statement subject to Section
1.3.

               (c)  Subject to the foregoing, the Company shall file a
registration statement covering the Registrable Securities and other securities
so requested to be registered as soon as practicable, and in any event within 20
days, after receipt of the request or requests of the Holders. Registrations
effected pursuant to this Section 1.4 shall not be counted as demands for
registration or registrations effected pursuant to Sections 1.2 or 1.3,
respectively. The number of registrations that may be requested pursuant to this
Section 1.4 is unlimited.

          1.5  OBLIGATIONS OF THE COMPANY. Whenever required under this Section
1 to effect the registration of any Registrable Securities, the Company shall,
as expeditiously as reasonably possible:

               (a)  Prepare and file with the SEC a registration statement with
respect to such Registrable Securities and use its best efforts to cause such
registration statement to become and remain effective, and, upon the request of
the Holders of a majority of the Registrable Securities registered thereunder,
keep such registration statement effective for up to 120 days.

               (b)  Prepare and file with the SEC such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration statement as may be necessary to comply with the
provisions of the Securities Act with respect to the disposition of all
securities covered by such registration statement for up to 120 days.



                                       5
<PAGE>   29

               (c)  Furnish to the Holders such numbers of copies of a
prospectus, including a preliminary prospectus, in conformity with the
requirements of the Securities Act, and such other documents as they may
reasonably request in order to facilitate the disposition of Registrable
Securities owned by them.

               (d)  Use its best efforts to register and qualify the securities
covered by such registration statement under such other securities or Blue Sky
laws of such jurisdictions as shall be reasonably requested by the Holders,
provided that the Company shall not be required in connection therewith or as a
condition thereto to qualify to do business or to file a general consent to
service of process in any such states or jurisdictions unless the Company is
required to do so under the Securities Act.

               (e)  In the event of any underwritten public offering, enter into
and perform its obligations under an underwriting agreement, in usual and
customary form, with the managing underwriter of such offering. Each Holder
participating in such underwriting shall also enter into and perform its
obligations under such an agreement.

               (f)  Notify each Holder of Registrable Securities covered by such
registration statement at any time when a prospectus relating thereto is
required to be delivered under the Securities Act of the happening of any event
as a result of which the prospectus included in such registration statement, as
then in effect, includes an untrue statement of a material fact or omits to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading in the light of the circumstances then
existing.

               (g)  Cause all such Registrable Securities registered pursuant
hereunder to be listed on each securities exchange or the Nasdaq Stock Market on
which similar securities issued by the Company are then listed.

               (h)  Provide a transfer agent and registrar for all Registrable
Securities registered pursuant hereunder and a CUSIP number for all such
Registrable Securities, in each case not later than the effective date of such
registration.

               (i)  Use its best efforts to furnish, at the request of any
Holder requesting registration of Registrable Securities pursuant to this
Section 1, on the date that such Registrable Securities are delivered to the
underwriters for sale in connection with a registration pursuant to this Section
1, if such securities are being sold through underwriters, or, if such
securities are not being sold through underwriters, on the date that the
registration statement with respect to such securities becomes effective, (i) an
opinion, dated such date, of the counsel representing the Company for the
purposes of such registration, in form and substance as is customarily given to
underwriters in an underwritten public offering, addressed to the underwriters,
if any, and to the Holders requesting registration of Registrable Securities and
(ii) a letter dated such date, from the independent certified public accountants
of the Company, in form and substance as is customarily given by independent
certified public accountants to underwriters in an underwritten public offering,
addressed to the underwriters, if any, and to the Holders requesting
registration of Registrable Securities.



                                       6
<PAGE>   30

          1.6  FURNISH INFORMATION. It shall be a condition precedent to the
obligations of the Company to file a registration statement pursuant to this
Section 1 with respect to the Registrable Securities of any selling Holder that
such Holder shall furnish to the Company such information regarding itself, the
Registrable Securities held by it, and the intended method of disposition of
such securities as shall be reasonably requested by the Company in writing to
effect the registration of such Holder's Registrable Securities. The Company
shall have no obligation with respect to any registration requested pursuant to
Section 1.2 or Section 1.4 of this Agreement if, as a result of the application
of the preceding sentence, the number of shares or the anticipated aggregate
offering price of the Registrable Securities to be included in the registration
does not equal or exceed the number of shares or the anticipated aggregate
offering price required to originally trigger the Company's obligation to
initiate such registration as specified in Section 1.2(a) or Section 1.4(b)(ii),
whichever is applicable.

          1.7  EXPENSES OF REGISTRATION.

               (a)  DEMAND REGISTRATION. All expenses (other than underwriting
discounts and commissions) incurred in connection with registrations, filings or
qualifications pursuant to Section 1.2, including (without limitation) all
registration, filing and qualification fees, printers' and accounting fees, fees
and disbursements of counsel for the Company, and the reasonable fees and
disbursements of one counsel for the selling Holders selected by them with the
approval of the Company, which approval shall not be unreasonably withheld,
shall be borne by the Company; provided, however, that the Company shall not be
required to pay for any expenses of any registration proceeding begun pursuant
to Section 1.2 if the registration request is subsequently withdrawn prior to
effectiveness at the request of the Holders of a majority of the Registrable
Securities to be registered (in which case all participating Holders shall bear
such expenses with each Holder paying its pro rata portion of such expenses
based on the number of Registrable Securities with respect to which each such
Holder has requested registration), unless the Holders of a majority of the
Registrable Securities agree to forfeit their right to one demand registration
pursuant to Section 1.2.

               (b)  COMPANY REGISTRATION. All expenses (other than underwriting
discounts and commissions) incurred in connection with registrations, filings or
qualifications of Registrable Securities pursuant to Section 1.3 for each Holder
(which right may be assigned as provided in Section 1.12), including (without
limitation) all registration, filing, and qualification fees, printers' and
accounting fees, fees and disbursements of counsel for the Company and the
reasonable fees and disbursements of one counsel for the selling Holder or
Holders selected by them with the approval of the Company, which approval shall
not be unreasonably withheld, shall be borne by the Company.

               (c)  REGISTRATION ON FORM S-3. All expenses (other than
underwriters' discounts or commissions) incurred in connection with a
registration requested pursuant to Section 1.4, including (without limitation)
all registration, filing, qualification, printers' and accounting fees and the
reasonable fees and disbursements of one counsel for the selling Holder or
Holders selected by them with the approval of the Company, which approval shall
not be unreasonably withheld, and counsel for the Company, shall be borne by the
Company.



                                       7
<PAGE>   31

          1.8  UNDERWRITING REQUIREMENTS. In connection with any offering
involving an underwriting of shares of the Company's capital stock, the Company
shall not be required under Section 1.3 to include any of the Holders'
securities in such underwriting unless they accept the terms of the underwriting
as agreed upon between the Company and the underwriters selected by it (or by
other persons entitled to select the underwriters), and then only in such
quantity as the underwriters determine in their sole discretion will not
jeopardize the success of the offering by the Company. If the total amount of
securities, including Registrable Securities, requested by stockholders to be
included in such offering exceeds the amount of securities to be included by
persons other than the Company that the underwriters determine in their sole
discretion is compatible with the success of the offering, then the Company
shall be required to include in the offering only that number of such
securities, including Registrable Securities, which the underwriters determine
in their sole discretion will not jeopardize the success of the offering (the
securities so included to be apportioned pro rata among the selling stockholders
according to the total amount of securities entitled to be included therein
owned by each selling stockholder or in such other proportions as shall mutually
be agreed to by such selling stockholders) but in no event shall the amount of
securities of the selling Holders included in the offering be reduced below 20%
of the total amount of securities included in such offering, unless such
offering is the initial public offering of the Company's securities, in which
case, the selling stockholders may be excluded entirely if the underwriters make
the determination described above and no other stockholder's securities are
included.

          1.9  DELAY OF REGISTRATION. No Holder shall have any right to obtain
or seek an injunction restraining or otherwise delaying any such registration as
the result of any controversy that might arise with respect to the
interpretation or implementation of this Section 1.

          1.10 INDEMNIFICATION. In the event any Registrable Securities are
included in a registration statement under this Section 1:

               (a)  To the extent permitted by law, the Company will indemnify
and hold harmless each Holder, each of its officers, directors, partners,
members, any underwriter (as defined in the Securities Act) for such Holder and
each person, if any, who controls such Holder or underwriter within the meaning
of the Securities Act or the Exchange Act, against any losses, claims, damages
or liabilities (or actions, proceedings or settlements in respect thereof),
whether joint or several, to which they may become subject under the Securities
Act, the Exchange Act or other federal or state law, insofar as such losses,
claims, damages or liabilities (or actions, proceedings or settlements in
respect thereof) arise out of or are based upon any of the following statements,
omissions or violations (collectively a "Violation"): (i) any untrue statement
or alleged untrue statement of a material fact contained in such registration
statement, including any preliminary prospectus or final prospectus contained
therein or any amendments or supplements thereto, (ii) the omission or alleged
omission to state therein a material fact required to be stated therein, or
necessary to make the statements therein not misleading, or (iii) any violation
or alleged violation by the Company of the Securities Act, the Exchange Act, any
state securities law or any rule or regulation promulgated under the Securities
Act, the Exchange Act or any state securities law; and the Company will pay to
each such Holder, each of its officers, directors, partners, members,
underwriter or controlling person, as incurred, any legal or other expenses
reasonably incurred by them in connection with investigating or defending any
such



                                       8
<PAGE>   32

loss, claim, damage, expenses or liability (or actions, proceedings or
settlements in respect thereof); provided, however, that the indemnity agreement
contained in this Section 1.10(a) shall not apply to amounts paid in settlement
of any such loss, claim, damage or liability (or actions, proceedings or
settlements in respect thereof) if such settlement is effected without the
consent of the Company (which consent shall not be unreasonably withheld), nor
shall the Company be liable to any Holder, each of its officers, directors,
partners, members, underwriter or controlling person for any such loss, claim,
damage or liability (or actions, proceedings or settlements in respect thereof)
to the extent that it arises out of or is based upon a Violation which occurs in
reliance upon and in conformity with written information furnished expressly for
use in connection with such registration by any such Holder, officer, director,
partner, member, underwriter or controlling person.

               (b)  To the extent permitted by law, each selling Holder,
severally and not jointly, will indemnify and hold harmless the Company, each of
its directors, each of its officers who has signed the registration statement,
each person, if any, who controls the Company within the meaning of the
Securities Act, any underwriter, any other Holder selling securities in such
registration statement and any controlling person of any such underwriter or
other Holder, against any losses, claims, damages or liabilities (or actions,
proceedings or settlements in respect thereof), whether joint or several, to
which any of the foregoing persons may become subject, under the Securities Act,
the Exchange Act or other federal or state law, insofar as such losses, claims,
damages or liabilities (or actions, proceedings or settlements in respect
thereof) arise out of or are based upon any Violation, in each case to the
extent (and only to the extent) that such Violation occurs in reliance upon and
in conformity with written information furnished by such Holder expressly for
use in connection with such registration; and each such Holder will pay, as
incurred, any legal or other expenses reasonably incurred by any person intended
to be indemnified pursuant to this Section 1.10(b), in connection with
investigating or defending any such loss, claim, damage, expenses or liability
(or actions, proceedings or settlements in respect thereof); provided, however,
that the indemnity agreement contained in this Section 1.10(b) shall not apply
to amounts paid in settlement of any such loss, claim, damage or liability (or
actions, proceedings or settlements in respect thereof), if such settlement is
effected without the consent of the Holder, which consent shall not be
unreasonably withheld; provided, that in no event shall any indemnity under this
Section 1.10(b) exceed the net proceeds from the offering received by such
Holder, except in the case of willful fraud by such Holder.

               (c)  Promptly after receipt by an indemnified party under this
Section 1.10 of notice of the commencement of any action (including any
governmental action), such indemnified party will, if a claim in respect thereof
is to be made against any indemnifying party under this Section 1.10, deliver to
the indemnifying party a written notice of the commencement thereof and the
indemnifying party shall have the right to participate in, and, to the extent
the indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an indemnified party
(together with all other indemnified parties which may be represented without
conflict by one counsel) shall have the right to retain one separate counsel,
with the reasonable fees and expenses to be paid by the indemnifying party, if
representation of such indemnified party by the counsel retained by the
indemnifying party would be inappropriate due to actual or potential differing
interests between such indemnified



                                       9
<PAGE>   33

party and any other party represented by such counsel in such proceeding. The
failure to deliver written notice to the indemnifying party within a reasonable
time of the commencement of any such action, if prejudicial to its ability to
defend such action, shall relieve such indemnifying party of any liability to
the indemnified party under this Section 1.10, but the omission so to deliver
written notice to the indemnifying party will not relieve it of any liability
that it may have to any indemnified party otherwise than under this Section
1.10.

               (d)  If the indemnification provided for in this Section 1.10 is
held by a court of competent jurisdiction to be unavailable to an indemnified
party with respect to any loss, liability, claim, damage or expense referred to
therein, then the indemnifying party, in lieu of indemnifying such indemnified
party hereunder, shall contribute to the amount paid or payable by such
indemnified party as a result of such loss, liability, claim, damage, or expense
in such proportion as is appropriate to reflect the relative fault of the
indemnifying party on the one hand and of the indemnified party on the other in
connection with the statements or omissions that resulted in such loss,
liability, claim, damage or expense as well as any other relevant equitable
considerations; provided, that in no event shall any contribution by a Holder
under this Section 1.10(d) exceed the net proceeds from the offering received by
such Holder, except in the case of willful fraud by such Holder. The relative
fault of the indemnifying party and of the indemnified party shall be determined
by reference to, among other things, whether the untrue or alleged untrue
statement of a material fact or the omission to state a material fact relates to
information supplied by the indemnifying party or by the indemnified party and
the parties' relative intent, knowledge, access to information, and opportunity
to correct or prevent such statement or omission.

               (e)  Notwithstanding the foregoing, to the extent that the
provisions on indemnification and contribution contained in the underwriting
agreement entered into in connection with the underwritten public offering are
in conflict with the foregoing provisions, the provisions in the underwriting
agreement shall control.

               (f)  The obligations of the Company and Holders under this
Section 1.10 shall survive the completion of any offering of Registrable
Securities in a registration statement under this Section 1, and otherwise.

          1.11 REPORTS UNDER EXCHANGE ACT. With a view to making available to
the Holders the benefits of Rule 144 promulgated under the Securities Act and
any other rule or regulation of the SEC that may at any time permit a Holder to
sell securities of the Company to the public without registration or pursuant to
a registration on Form S-3, the Company agrees to:

               (a)  make and keep public information available, as those terms
are understood and defined in SEC Rule 144, at all times after 90 days after the
effective date of the first registration statement filed by the Company for the
offering of its securities to the general public so long as the Company remains
subject to the periodic reporting requirements under Sections 13 or 15(d) of the
Exchange Act;

               (b)  take such action, including the voluntary registration of
its Common Stock under Section 12 of the Exchange Act, as is necessary to enable
the Holders to utilize Form S-3 for the sale of their Registrable Securities,
such action to be taken as soon as




                                       10
<PAGE>   34

practicable after the end of the fiscal year in which the first registration
statement filed by the Company for the offering of its securities to the general
public is declared effective;

               (c)  file with the SEC in a timely manner all reports and other
documents required of the Company under the Securities Act and the Exchange Act;
and

               (d)  furnish to any Holder, so long as the Holder owns any
Registrable Securities, forthwith upon request (i) a written statement by the
Company that it has complied with the reporting requirements of SEC Rule 144 (at
any time after 90 days after the effective date of the first registration
statement filed by the Company), the Securities Act and the Exchange Act (at any
time after it has become subject to such reporting requirements), or that it
qualifies as a registrant whose securities may be resold pursuant to Form S-3
(at any time after it so qualifies), (ii) a copy of the most recent annual or
quarterly report of the Company and such other reports and documents so filed by
the Company, and (iii) such other information as may be reasonably requested in
availing any Holder of any rule or regulation of the SEC which permits the
selling of any such securities without registration or pursuant to such form.

          1.12 ASSIGNMENT OF REGISTRATION RIGHTS.  The rights to cause the
Company to register Registrable Securities pursuant to this Section 1 may be
assigned (but only with all related obligations) by a Holder to (i) any of its
affiliates, (ii) the holders of the equity securities of any Holder that is an
entity, (iii) any family member or trust for the benefit of any individual
Holder, or (iv) a transferee or assignee of at least 400,000 shares of
Registrable Securities (appropriately adjusted for any stock split, dividend,
combination, change in the conversion price of the Series A Preferred Stock or
other recapitalization) of such securities (or all of such Holder's shares, if
less than 400,000 shares) (collectively, a "Permitted Transferee"), provided
the Company is, within a reasonable time after such transfer, furnished with
written notice of the name and address of such transferee or assignee and the
securities with respect to which such registration rights are being assigned;
and provided, further, that such assignment shall be effective only if
immediately following such transfer the further disposition of such securities
by the transferee or assignee is restricted under the Securities Act. Any
permitted assignee under this Section 1.12 shall become a Holder hereunder.

          1.13 LIMITATIONS ON SUBSEQUENT REGISTRATION RIGHTS. From and after the
date of this Agreement, the Company shall not, without the prior written consent
of the Holders of a majority of the outstanding Registrable Securities, enter
into any agreement with any holder or prospective holder of any securities of
the Company which would allow such holder or prospective holder (a) to include
such securities in any registration filed under Section 1.2 hereof, unless under
the terms of such agreement, such holder or prospective holder may include such
securities in any such registration only to the extent that the inclusion of his
securities will not reduce the amount of the Registrable Securities of the
Holders which is included or (b) to make a demand registration which could
result in such registration statement being declared effective prior to the
earlier of either of the dates set forth in Section 1.2(a) or within 120 days of
the effective date of any registration effected pursuant to Section 1.2.



                                       11
<PAGE>   35

          1.14 "MARKET STAND-OFF" AGREEMENT.

               (a)  MARKET-STANDOFF PERIOD; AGREEMENT. In connection with the
initial public offering of the Company's securities and upon request of the
Company and the underwriters managing such offering of the Company's securities,
each Holder agrees not to sell, make any short sale of, loan, grant any option
for the purchase of, or otherwise dispose of any securities of the Company
(other than those included in the registration) without the prior written
consent of the Company or such underwriters, as the case may be, for such period
of time (not to exceed 180 days) from the effective date of such registration as
may be requested by the Company or such managing underwriters and to execute an
agreement reflecting the foregoing as may be requested by the underwriters at
the time of the Company's initial public offering.

               (b)  LIMITATIONS. The obligations described in Section 1.14(a)
shall apply only if all officers, directors and stockholders holding at least 2%
of the outstanding Registrable Securities enter into similar agreements, and
shall not apply to a registration relating solely to employee benefit plans, or
to a registration relating solely to a transaction pursuant to Rule 145 under
the Securities Act.

               (c)  STOP-TRANSFER INSTRUCTIONS. In order to enforce the
foregoing covenants, the Company may impose stop-transfer instructions with
respect to the securities of each Holder (and the securities of every other
person subject to the restrictions in Section 1.14(a)).

               (d)  TRANSFEREES BOUND. Each Holder agrees that it will not
transfer securities of the Company unless each transferee agrees in writing to
be bound by all of the provisions of this Section 1.14, provided that this
Section 1.14(d) shall not apply to transfers pursuant to a registration
statement.

          1.15 TERMINATION OF REGISTRATION RIGHTS. No Holder shall be
entitled to exercise any right provided for in this Section 1 after the earlier
of (i) five years following the consummation of a Qualified IPO, or (ii) such
time as Rule 144 or another similar exemption under the Securities Act is
available for the sale of all of such Holder's shares during a three-month
period without registration.

     2.   COVENANTS OF THE COMPANY.

          2.1  DELIVERY OF FINANCIAL STATEMENTS. The Company shall deliver to
each Holder of at least 250,000 shares (appropriately adjusted for any stock
split, dividend, combination or other recapitalization) of the Series A
Preferred Stock (or the Common Stock issued upon conversion thereof) (other than
a Holder reasonably deemed by the Company to be a competitor of the Company,
which shall not include any of the Investors that are original signatories to
the Purchase Agreement):

               (a)  as soon as practicable, but in any event within 90 days
after the end of each fiscal year of the Company, an income statement for such
fiscal year, a balance sheet of the Company and statement of stockholder's
equity as of the end of such year, and a statement of cash flows for such year,
such year-end financial reports to be in reasonable detail, prepared in
accordance with generally accepted accounting principles ("GAAP"), and audited
and certified



                                       12
<PAGE>   36

by an independent public accounting firm of nationally recognized
standing selected by the Company;

               (b)  as soon as practicable, but in any event within 30 days
after the end of each month, an unaudited income statement and a statement of
cash flows and balance sheet for and as of the end of such month, in reasonable
detail; and

               (c)  an annual budget and operating plan each fiscal year,
promptly after management has presented such budget and operating plan to the
Board.

          2.2  RIGHT OF FIRST OFFER. Subject to the terms and conditions
specified in this Section 2.2, the Company hereby grants to each Major Investor
(as hereinafter defined) a right of first offer with respect to future issuances
and sales by the Company of its Shares (as hereinafter defined). For purposes of
this Section 2.2, a "Major Investor" shall mean any person who holds, along with
its affiliates, directly or indirectly, at least 400,000 shares (appropriately
adjusted for any stock split, dividend, combination or other recapitalization)
of the Series A Preferred Stock (or the Common Stock issued upon conversion
thereof) issued pursuant to the Purchase Agreement. For purposes of this Section
2.2, Major Investor includes any general partners and affiliates of a Major
Investor. A Major Investor who chooses to exercise the right of first offer may
designate as purchasers under such right itself or its partners or affiliates in
such proportions as it deems appropriate.

          Each time the Company proposes to offer any shares of, or securities
convertible into or exercisable for any shares of, any class of its capital
stock ("Shares"), the Company shall first make an offering of such Shares to
each Major Investor in accordance with the following provisions:

               (a)  The Company shall deliver a notice by certified mail
("Notice") to the Major Investors stating (i) its bona fide intention to offer
such Shares, (ii) the number of such Shares to be offered, and (iii) the price
and terms, if any, upon which it proposes to offer such Shares.

               (b)  Within 15 calendar days after delivery of the Notice, the
Major Investor may elect to purchase or obtain, at the price and on the terms
specified in the Notice, up to that portion of such Shares which equals the
proportion that the number of shares of Common Stock issued and held, or
issuable upon conversion and exercise of all convertible or exercisable
securities then held, by such Major Investor bears to the total number of shares
of Common Stock then outstanding (assuming full conversion and exercise of all
convertible or exercisable securities). Such purchase shall be completed at the
same closing as that of any third party purchasers or at an additional closing
thereunder. The Company shall promptly, in writing, inform each Major Investor
that purchases all the shares available to it (each, a "Fully-Exercising
Investor") of any other Major Investor's failure to do likewise. During the
ten-day period commencing after receipt of such information, each
Fully-Exercising Investor shall be entitled to obtain that portion of the Shares
for which Major Investors were entitled to subscribe but which were not
subscribed for by the Major Investors that is equal to the proportion that the
number of shares of Common Stock issued and held, or issuable upon conversion
and exercise of all convertible or exercisable securities then held, by such
Fully-Exercising Investor bears to the



                                       13
<PAGE>   37

total number of shares of Common Stock then outstanding (assuming full
conversion and exercise of all convertible or exercisable securities).

               (c)  The Company may, during the 60-day period following the
expiration of the period provided in Section 2.2(b) hereof, offer the remaining
unsubscribed portion of the Shares to any person or persons at a price not less
than, and upon terms no more favorable to the offeree than those specified in
the Notice. If the Company does not enter into an agreement for the sale of the
Shares within such period, or if such agreement is not consummated within 90
days of the execution thereof, the right provided hereunder shall be deemed to
be revived and such Shares shall not be offered unless first reoffered to the
Major Investors in accordance herewith.

               (d)  The right of first offer in this Section 2.2 shall not be
applicable to:

                    (i)    Common Stock issued pursuant to a transaction
pursuant to which the Company sells, conveys, or otherwise disposes of all or
substantially all of its property or business or merges into or consolidates
with any other corporation (other than a wholly-owned subsidiary corporation) or
effect any other transaction or series of related transactions in which more
than fifty percent (50%) of the voting power of the Corporation is disposed of,

                    (ii)   Shares of Common Stock issuable or issued to
employees or directors of the Company directly or pursuant to a stock option
plan, restricted stock plan or other agreement approved by the Board,

                    (iii)  Capital stock, or options or warrants to purchase
capital stock, issued to financial institutions or lessors in connection with
commercial credit arrangements, equipment financings or similar transactions for
which the principal purpose is not to raise equity funding, each of which has
been approved by the Board,

                    (iv)   Capital stock or warrants or options to purchase
capital stock issued in connection with bona fide acquisitions, mergers or
similar transactions, each of which has been approved by the Board,

                    (v)    Capital stock or warrants or options to purchase
capital stock issued in connection with bona fide strategic partnerships or
licenses or acquisition of third party technology, each of which has been
approved by the Board,

                    (vi)   Shares of Common Stock issued or issuable upon
conversion of the Series A Preferred Stock,

                    (vii)  Shares of Common Stock issued or issuable in a public
offering approved by the Board prior to or in connection with which all
outstanding shares of Preferred Stock will be converted to Common Stock,

                    (viii) Shares of Common Stock issued or issuable with the
affirmative vote or written consent of at least a majority of the then
outstanding shares of Series A Preferred Stock, voting together as a class, or



                                       14
<PAGE>   38

                     (ix)  Shares of Common Stock issued pursuant to a Qualified
IPO.

In addition to the foregoing, the right of first offer in this Section 2.2 shall
not be applicable with respect to any Major Investor and any subsequent
securities issuance, if (i) at the time of such subsequent securities issuance,
the Major Investor is not an "accredited investor," as that term is defined in
Rule 501(a) under the Securities Act, or is not otherwise qualified to
participate in an offering exempt from registration under the Securities Act;
and (ii) such subsequent securities issuance is otherwise being offered only to
accredited investors.

                (e)  The right of a Major Investor under this Section 2.2 may
be assigned in whole or in part only to a transferee who will otherwise meet the
definition of a "Major Investor" after the assignment. In addition, in
connection with an exercise of the right under this Section 2.2, a Major
Investor may assign such right to an affiliate of such Major Investor.

          2.3   TERMINATION OF COVENANTS.

                (a)  The covenants set forth in Section 2.1 and Section 2.2
shall terminate as to each Holder and be of no further force or effect
immediately upon the consummation of a Qualified IPO

                (b)  The covenants set forth in Section 2.1 shall terminate as
to each Holder and be of no further force or effect when the Company first
becomes subject to the periodic reporting requirements of Sections 13 or 15(d)
of the Exchange Act, if this occurs earlier than the events described in Section
2.3(a) above.

     3.   MISCELLANEOUS.

          3.1  SUCCESSORS AND ASSIGNS. Except as otherwise provided in this
Agreement, the terms and conditions of this Agreement shall inure to the benefit
of and be binding upon the respective permitted successors and assigns of the
parties (including transferees of any of the Series A Preferred Stock or any
Common Stock issued upon conversion thereof). Nothing in this Agreement, express
or implied, is intended to confer upon any party other than the parties hereto
or their respective successors and assigns any rights, remedies, obligations, or
liabilities under or by reason of this Agreement, except as expressly provided
in this Agreement.

          3.2  AMENDMENTS AND WAIVERS. Any term of this Agreement may be amended
or waived only with the written consent of the Company and the holders of a
majority of the Registrable Securities then outstanding; ; provided, however,
that any such amendment or waiver cannot be effected in accordance with this
Section 3.2 if it adversely affects the rights of any Holder hereunder or
increases the obligations of any Holder hereunder unless the affected party,
expressly consents, in writing, to such amendment or waiver.. Any amendment or
waiver effected in accordance with this paragraph shall be binding upon each
party to the Agreement, whether or not such party has signed such amendment or
waiver, each future holder of all such Registrable Securities, and the Company.



                                       15
<PAGE>   39

          3.4  NOTICES. Unless otherwise provided, any notice required or
permitted by this Agreement shall be in writing and shall be deemed sufficient
upon delivery, when delivered personally or by overnight courier or sent by
telegram or fax, or forty-eight (48) hours after being deposited in the U.S.
mail, as certified or registered mail, with postage prepaid, and addressed to
the party to be notified at such party's address or fax number as set forth on
Exhibit A to the Purchase Agreement or as subsequently modified by written
notice.

          3.5  SEVERABILITY. Any provision of this Agreement which is invalid or
unenforceable shall be ineffective to the extent of such invalidity or
unenforceability, provided that such invalidity or unenforceability does not
deny any party the material benefits of the transactions for which it has
bargained, such invalidity or unenforceability shall not affect in any way the
remaining provisions hereof.

          3.6  GOVERNING LAW. This Agreement and all acts and transactions
pursuant hereto shall be governed, construed and interpreted in accordance with
the laws of the State of Delaware, without giving effect to principles of
conflicts of law.

          3.7  COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

          3.8  TITLES AND SUBTITLES. The titles and subtitles used in this
Agreement are used for convenience only and are not to be considered in
construing or interpreting this Agreement.

          3.9  AGGREGATION OF STOCK. All shares of the Preferred Stock and
Registrable Securities held or acquired by affiliated entities or persons shall
be aggregated together for the purpose of determining the availability of any
rights under this Agreement; provided, that no Investor shall be deemed an
affiliated entity of another Investor for purposes of this Agreement solely by
reason of any equity investment by such Investor in such other Investor.

                            [Signature Pages Follow]



                                       16
<PAGE>   40



     The parties have executed this Investors' Rights Agreement as of the date
first above written.

COMPANY:

INCICSENT, INC.

By:
   ------------------------------
Name:
     ----------------------------
Title:
     ----------------------------

INVESTORS:

METROCALL, INC.                                AETHER SYSTEMS, INC.

By:                                     By:
   ------------------------------          ------------------------------
Name:                                   Name:
     ----------------------------            ----------------------------
Title:                                  Title:
     ----------------------------            ----------------------------

PSINET INC.                             HMTF BRIDGE MC II, LLC

By:                                     By:
  ------------------------------            ------------------------------
Name:                                   Name:
     ----------------------------             ----------------------------
Title:                                  Title:
     ----------------------------             ----------------------------
DB CAPITAL INVESTORS, L.P.              ROBERT H. LESSIN

BY: DB CAPITAL PARTNERS, L.P.,          VENTURE CAPITAL LLC
 ITS GENERAL PARTNER
BY: DB CAPITAL PARTNERS, INC.

By:                                     By:
   ------------------------------          ------------------------------
Name:                                   Name:
     ----------------------------             ----------------------------
Title:                                  Title:
     ----------------------------             ----------------------------

                 [Signature Page To Investors' Rights Agreement]




                                       17
<PAGE>   41




                                    EXHIBIT A

                              SCHEDULE OF INVESTORS

<TABLE>
<CAPTION>
                INVESTOR                                     NUMBER OF SHARES
  -----------------------------------------------------------------------------
  <S>                                                            <C>
  METROCALL, INC.                                                    7,500,000
  -----------------------------------------------------------------------------
  AETHER SYSTEMS, INC.                                               4,950,000
  -----------------------------------------------------------------------------
  PSINET INC.                                                          950,000
  -----------------------------------------------------------------------------
  HMTF BRIDGE MC II, LLC                                               950,000
  -----------------------------------------------------------------------------
  DB CAPITAL INVESTORS, L.P.                                           400,000
  -----------------------------------------------------------------------------
  ROBERT H. LESSIN VENTURE CAPITAL LLC                                 250,000
  -----------------------------------------------------------------------------

  TOTAL                                                             15,000,000
  -----------------------------------------------------------------------------

</TABLE>




                                       18

<PAGE>   42
                                                                       EXHIBIT G

                                 INCISCENT, INC.

                                CO-SALE AGREEMENT

     This Co-Sale Agreement (the "Agreement") is made and entered into as of
_________ ___, 2000 by and among the individuals listed on Exhibit A to this
Agreement (each a "Founder" and collectively the "Founders"), Inciscent, Inc., a
Delaware corporation (the "Company"), and the holders of Series A Preferred
Stock of the Company listed on Exhibit B to this Agreement (each an "Investor"
and collectively the "Investors"). Collectively, the Founders and the Investors
are referred to herein as the "Owners."

                                    RECITALS

     The Company and the Investors have entered into a Series A Preferred Stock
Purchase Agreement (the "Purchase Agreement") dated as of February 8, 2000,
pursuant to which the Company has agreed to sell to the Investors and the
Investors have agreed to purchase from the Company shares of the Company's
Series A Preferred Stock (the "Series A Preferred Stock"). A condition to the
Investors' obligations under the Purchase Agreement is that the Company, the
Founders and the Investors enter into this Agreement in order to provide the
Investors and Founders the opportunity to purchase and/or participate, upon the
terms and conditions set forth in this Agreement, in subsequent sales by the
Investors and Founders of shares of the Company's capital stock. The Company and
the Founders desire to induce the Investors to purchase shares of Series A
Preferred Stock pursuant to the Purchase Agreement by agreeing to the terms and
conditions set forth below.

                                    AGREEMENT

     The parties agree as follows:

     1.   Rights of First Refusal.

          1.1. No Owner shall, whether voluntarily or by operation of law, sell,
transfer, pledge, hypothecate, gift, bequest, devise, assign or otherwise
dispose of (collectively, "transfer") any shares of the Company's common stock,
par value $0.0001 per share (the "Common Stock"), or Series A Preferred Stock,
whether now owned or hereafter acquired by such Founder or Investor (the
"Shares"), except for "Permitted Transfers" (as defined in Subsection 1.5 below)
or pursuant to this Section 1 or Section 2 below.

          1.2. In the event that an Owner wishes to transfer Shares (a "Selling
Stockholder"), other than as a Permitted Transfer, such Selling Stockholder
shall deliver a written notice (the "Sale Notice") to the Company and to each of
the Founders and Investors who owns, alone or together with its affiliates, at
least 250,000 Shares (appropriately adjusted for any stock split, dividend,
combination, change in the conversion price of the Series A Preferred



                                        1

<PAGE>   43

Stock or other recapitalization) (each a "Holder"), disclosing in reasonable
detail the identity of the proposed transferees, the number of Shares to be
transferred (the "Offered Shares"), and the terms and conditions of the proposed
transfer. To the extent that the Selling Stockholder is a Founder and the
Offered Shares are subject to the Company's right of first refusal pursuant to a
stock purchase agreement or stock restriction agreement ("Founders Shares"), the
Company shall have a period of 30 days from the date of delivery of the Sale
Notice to give written notice (the "Company Notice") to the Selling Stockholder
of its decision whether or not to purchase some or all of the Offered Shares.
The Company shall simultaneously deliver a copy of the Company Notice to each of
the Holders.

          1.3. (a) In the case of Founders Shares, if the Company elects not to
purchase all of the Offered Shares, or if the Offered Shares are not Founders
Shares, the Holders shall have the option, for seven (7) days following their
receipt of (i) the Company Notice, in the case of Founders Shares, or (ii) the
Sale Notice in the case of Shares other than Founders Shares, to purchase some
or all of the remaining Offered Shares at the price and upon the terms set forth
in the Sale Notice. Each Holder shall have the right to purchase its pro rata
share of the Offered Shares, or remaining Offered Shares in the case of Founders
Shares, which pro rata share represents the ratio of the total number of shares
of Common Stock and Series A Preferred Stock (on an as-converted basis) then
held by the Holder to the total number of shares of Common Stock and Series A
Preferred Stock then outstanding (on an as-converted basis), calculated on a
fully-diluted basis (including shares issuable upon conversion, exchange or
exercise of all outstanding warrants, options and other convertible and
exchangeable securities and shares reserved for future issuance under any equity
incentive plans adopted by the Board of Directors). In the event a Holder elects
to purchase some or all of the remaining Offered Shares, it shall give written
notice of its election to the Selling Stockholder within such seven-day period,
and the settlement of the sale of such Offered Shares shall be made as provided
below in Subsection 1.4 of this Section 1.

               (b) Each Holder will have the right of reallotment such that, if
any other Holder fails to fully exercise the right to purchase its full pro rata
share of the Offered Shares pursuant to Section 1.3(a), the other participating
Holders may exercise an additional right to purchase, on a pro rata basis, the
Offered Shares not previously purchased.

          1.4  The closing of the purchase and sale of the Offered Shares shall
take place on a date agreed upon by the Selling Stockholder and purchaser or
purchasers of the Offered Shares, but in any event:

               (a) in the event the Company is the purchaser, no later than the
first business day following the 30th day from the date of (a) the Company
Notice, in the case of Founders Shares or (b) Sales Notice in the case of Shares
other than Founders Shares, at the principal office of the Company on the terms
and conditions set forth in the Sale Notice; or

               (b) in the event the Company is not the purchaser, no later than
the first business day following the 60th day from the date of (a) the Company
Notice, in the case of Founders Shares or (b) Sales Notice in the case of Shares
other than Founders Shares, at the principal office of the Company on the terms
and conditions set forth in the Sale Notice.



                                        2

<PAGE>   44

          1.5  For purposes of this Section 1, a "Permitted Transfer" shall mean

               (a) Any repurchase of Common Stock by the Company pursuant to a
right of repurchase upon the termination of the transferring Owner's employment
or consulting relationship with the Company;

               (b) Any bona fide gift to a charitable organization;

               (c) Any transfer to the transferring Owner's Affiliate, ancestor,
descendant, sibling or spouse or to a trust for their benefit or a partnership
that is owned entirely by the transferring Owner's ancestors, descendants,
siblings or spouse; or

               (d) Any distribution of securities without consideration to
holders of equity interests in the distributing Owner;

provided, in each case, that the pledgee, transferee or donee (each a "Permitted
Transferee") shall furnish the Company and the Owners with a written agreement
to be bound by and comply with all provisions of this Agreement and the Voting
Agreement dated as of ____________ ____, 2000 by and among the Company, the
Founders and the Investors (the "Voting Agreement"); and provided, further, that
if the transferor is an Investor, the Permitted Transferee shall in addition
furnish the Company and the other Investors with a written agreement to be bound
by and comply with all provisions of the Investors' Rights Agreement dated as of
______________ ____, 2000 by and among the Company and the Investors (the
"Investors' Rights Agreement"); and provided, further, that the right of first
refusal in Section 1 and the right of co-sale in Section 2, in either case, may
be waived in writing by the holders of a majority in interest (on an
as-converted basis) of the Shares. A Permitted Transferee shall be deemed to be
an Owner.

          1.6  For purposes of Section 1.5 an "Affiliate" of a Person shall mean
any Person that directly or indirectly, through one or more intermediaries,
controls, is controlled by, or is under common control with, the Person
specified. The term "control" (including the correlative terms "controlled by"
and "under common control with") as used with respect to any Person means the
possession, directly or indirectly, of the power to direct or to cause the
direction of the management and policies of such Person, whether through the
ownership of voting securities, by contract, or otherwise. "Person" shall mean
any individual, corporation (including non-profit corporation), general or
limited partnership, limited liability company, joint venture, estate, trust,
association, organization or other entity.

     2.   Co-Sale Right. To the extent that the right of first refusal set forth
in Section 1 is not fully exercised by the Holders, each Holder shall have the
right (the "Co-Sale Right"), exercisable upon written notice to the Company
within seven (7) days after the expiration of the right of first refusal set
forth in Section 1 to participate in the Selling Stockholder's sale of the
Offered Shares pursuant to the specified terms and conditions of the Sale
Notice. To the extent a Holder exercises such Co-Sale Right in accordance with
the terms and conditions set forth below, the number of Shares which the Selling
Stockholder may sell shall be correspondingly reduced. The Co-Sale Right shall
be subject to the following terms and conditions:



                                        3

<PAGE>   45

               (a) Calculation of Shares. Each Holder may sell all or any part
of that number of shares of stock (including Series A Preferred Stock, Common
Stock and Common Stock issuable upon conversion of Series A Preferred Stock or
any stock received in connection with any stock dividend, stock split or other
reclassification of any such stock) (the "Conversion Shares") equal to the
product obtained by multiplying (i) the aggregate number of Shares subject to
the Co-Sale Right by (ii) a fraction, the numerator of which is the number of
Conversion Shares at the time owned by such Holder and the denominator of which
is the sum of (A) the total number of Conversion Shares at the time owned by all
Holders participating in such sale plus (B) the total number of Shares at the
time owned by the Selling Stockholder.

               (b) Delivery of Certificates. Each Holder may effect its
participation in the sale by delivering to the Selling Stockholder for transfer
to the prospective purchaser one or more certificates, properly endorsed for
transfer, which represent the Conversion Shares which such Holder elects to
sell.

     3.   Put Option. In the event any Selling Stockholder transfers any Shares
in contravention of the Co-Sale Right in Section 2 (a "Prohibited Transfer"), to
the extent that such transfer is valid and recorded on the books of and
recognized by the Company, each Holder, in addition to such other remedies as
may be available at law, in equity or hereunder, will have the right to sell to
the Selling Stockholder, and in the event such Holder exercises such right the
Selling Stockholder shall be obligated to purchase from such Holder, the type
and number of Shares that such Holder would have been entitled to transfer to
the third-party transferee pursuant to Section 2 above had the Prohibited
Transfer been effected pursuant to and in compliance with the terms of this
Agreement. Such sale is to be made on the following terms and conditions:

               (a) the price per Share at which the Shares are to be sold to the
Selling Stockholder shall be the price per Share paid by the third-party
transferee in the Prohibited Transfer;

               (b) each Holder must exercise the right to sell pursuant to this
Section 3 within sixty (60) days after the later of the dates on which the
Holder (i) received notice of the Prohibited Transfer, or (ii) otherwise became
aware of the Prohibited Transfer, and each Holder shall, in order to exercise
the right created hereby, deliver to the Selling Stockholder the certificate or
certificates representing the Shares to be sold, each certificate to be properly
endorsed for transfer; and

               (c) the Selling Stockholder shall, upon receipt of the
certificate or certificates for the Shares to be sold by a Holder pursuant to
this Section 3, pay the aggregate purchase price therefor, as specified in
clause (a) above, in cash or by other means acceptable to the Holder.

     4.   Assignment of Rights. The rights of a Holder set forth in Sections 1,
2 and 3 may be assigned (but only with all related obligations) only to a
Permitted Transferee or to a transferee or assignee of at least 400,000
Conversion Shares (appropriately adjusted for any stock split, dividend,
combination, change in the conversion price of the Series A Preferred Stock or
other recapitalization) (or all of such Holder's Conversion Shares, if less),
provided that



                                        4

<PAGE>   46

(i) the Company is, within a reasonable time after such transfer, furnished with
written notice of the name and address of such transferee or assignee and the
securities with respect to which such rights are being assigned, (ii) such
transferee agrees in writing to be bound by the provisions of this Agreement and
the Voting Agreement and (iii) if the transferor is an Investor, such transferee
in addition agrees in writing to be bound by the provisions of the Investors'
Rights Agreement.

     5.   Drag-Along Rights. In the event that one or more Owners propose to
sell shares of stock (including Series A Preferred Stock, Common Stock and
Common Stock issuable upon conversion of Series A Preferred Stock or any stock
received in connection with any stock dividend, stock split or other
reclassification of any such stock) (the "Drag-Along Shares") to a
non-affiliated third party on an arm's-length basis, other than pursuant to a
transaction that is contemplated in Section 1.5(a), (b), (c) or (d), if the
aggregate number of Drag-Along Shares proposed to be sold by such selling Owners
constitutes at least 66.67 % of the total number of shares of Common Stock
(including shares of Common Stock issuable upon conversion of Series A Preferred
Stock) then outstanding, the selling Owners shall have the right to require all
(but not less than all) other Owners to sell all of the Drag-Along Shares held
by such other Owners to such third party, provided that the terms of such sale
are equivalent for all Owners (including the consideration received by each
Owner for each Drag-Along Share, taking into account the type of stock
transferred).

     In the event that one or more Owners wish to exercise their rights pursuant
to this Section 5, such selling Owner(s) shall deliver a written notice to the
Company and to each of the other Owners, disclosing in reasonable detail the
identity of the proposed transferees, the number of shares proposed to be sold
by the selling Owner(s) and the terms and conditions of the proposed sale. Such
notice shall include the closing date and instructions in reasonable detail for
the proposed sale, which closing shall take place no earlier than 30 days
following the date of the notice.

     6.   Termination of Agreement. This Agreement shall terminate in its
entirety on the earlier of (a) consummation of the sale of the Company's Common
Stock in a firm commitment underwritten public offering pursuant to a
registration statement under the Securities Act of 1933, as amended, that
results in aggregate cash proceeds to the Company of at least $20,000,000 (net
of underwriting discounts and commissions), or (b) consummation of a transaction
in which the Company shall sell, convey, or otherwise dispose of all or
substantially all of its property or business or merge into or consolidate with
any other corporation (other than a wholly-owned subsidiary corporation) or
effect any other transaction or series of related transactions in which at least
50% of the voting power of the Company is disposed of; provided that this
Agreement shall not be terminated following a merger effected solely for the
purpose of changing the domicile of the Company.

     7.   Legends. In addition to any other legend required by law or agreements
among the parties, each certificate representing Founders' or Investors' shares
of Common Stock or Series A Preferred Stock of the Company must be endorsed by
the Company with a legend reading as follows:



                                        5

<PAGE>   47

          "THE SHARES EVIDENCED HEREBY ARE SUBJECT TO A CO-SALE AGREEMENT BY AND
     AMONG THE COMPANY, THE FOUNDERS AND THE INVESTORS (A COPY OF WHICH MAY BE
     OBTAINED FROM THE COMPANY), AND BY ACCEPTING ANY INTEREST IN SUCH SHARES
     THE PERSON ACCEPTING SUCH INTEREST SHALL BE DEEMED TO AGREE AND SHALL
     BECOME BOUND BY ALL THE PROVISIONS OF SAID CO-SALE AGREEMENT."

     6.   Amendment; Waiver. Any term hereof may be amended or waived with the
written consent of the Company, holders of a majority of the Series A Preferred
Stock (or the equivalent amount of Common Stock issued or issuable upon
conversion of the Series A Preferred Stock), or their respective successors and
assigns, and holders of a majority of the Common Stock held by the Founders, or
their respective successors and assigns; provided, however, that any such
amendment or waiver cannot be effected in accordance with this Section 6 if it
adversely the rights of any Owner hereunder or increases the obligations of any
Owner hereunder unless the affected Owner expressly consents, in writing, to
such amendment or waiver. Any amendment or waiver effected in accordance with
this Section 6 shall be binding upon the Company, the holders of Series A
Preferred Stock and any holder of the Common Stock held by the Founders, and
each of their respective successors and assigns.

     7.   Notices. Any notice required or permitted by this Agreement shall be
in writing and shall be deemed sufficient on the date of delivery, when
delivered personally or by overnight courier or sent by telegram or fax, or
forty-eight (48) hours after being deposited in the U.S. mail, as certified or
registered mail, with postage prepaid, and addressed to the party to be notified
at such party's address as set forth on Exhibit C hereto, or as subsequently
modified by written notice.

     8.   Severability. Any provision of this Agreement which is invalid or
unenforceable shall be ineffective to the extent of such invalidity or
unenforceability, provided that such invalidity or unenforceability does not
deny any party the material benefits of the transactions for which it has
bargained and such invalidity or unenforceability shall not affect in any way
the remaining provisions hereof.

     9.   Governing Law. This Agreement and all acts and transactions pursuant
hereto and the rights and obligations of the parties hereto shall be governed,
construed and interpreted in accordance with the laws of the State of Delaware,
without giving effect to principles of conflicts of law.

     10.  Counterparts. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original and all of which
together shall constitute one instrument.

     11.  Successors and Assigns. The terms and conditions of this Agreement
shall inure to the benefit of and be binding upon the respective successors and
assigns of the parties. Nothing in this Agreement, express or implied, is
intended to confer upon any party other than the parties hereto or their
respective successors and assigns any rights, remedies, obligations,



                                        6

<PAGE>   48

or liabilities under or by reason of this Agreement, except as expressly
provided in this Agreement.

     12.  Entire Agreement. This Agreement constitutes the entire agreement
between the parties hereto pertaining to the subject matter hereof, and any and
all other written or oral agreements relating to the subject matter hereof
existing between the parties hereto are expressly canceled.

                            [Signature Pages Follow]



                                        7

<PAGE>   49

     The parties have executed this Agreement as of the date first written
above.

INCISCENT, INC.


By:
   -------------------------

Name:
     ------------------------------
          (print)

Title:
      -----------------------------

                   [Founders' Signatures Appear on Next Page]



                                        8

<PAGE>   50

FOUNDERS:


- -----------------------------
William L. Collins, III


- -----------------------------
Steven D. Jacoby


- -----------------------------
Vincent D. Kelly


- -----------------------------
Thomas Matthews


- -----------------------------
Dick Johnston


- -----------------------------
Francis Martin


- -----------------------------
Ron Aprahamian


- -----------------------------
Royce Yudcoff


- -----------------------------
Harry Brock


- -----------------------------
Jackie Kimzee


- -----------------------------
Max Hopper


- -----------------------------
Ed Jungerman


- -----------------------------
Michael Greene


- -----------------------------
Bonnie K. Culp



                                        9

<PAGE>   51


- -----------------------------
Randy Forster


- -----------------------------
Albert Gencarella


- -----------------------------
Kenneth Goldstein


- -----------------------------
Steve Marinaro


- -----------------------------
Stan Sech


- -----------------------------
Jeffrey A. Owens


- -----------------------------
Bob Pawa


- -----------------------------
Michael Scanlon


- -----------------------------
Jim Boso


- -----------------------------
Mark S. Dipple


- -----------------------------
Dean Finkenburg


- -----------------------------
Tony Hairston


- -----------------------------
Roman Kozak


- -----------------------------
Pam Mann


- -----------------------------
James McWhirter



                                       10

<PAGE>   52


- -----------------------------
Robert W. Carpenter


- -----------------------------
B. William Caton II


- -----------------------------
Robert M Chiatello


- -----------------------------
Ellen Crawford


- -----------------------------
Richard D Dewey, Jr.


- -----------------------------
Peter Dubois


- -----------------------------
Bill Harrell


- -----------------------------
Kevin Hayes


- -----------------------------
Mack Henderson


- -----------------------------
Bill Jones


- -----------------------------
Rob Griffen


- -----------------------------
Paul J. Liberty


- -----------------------------
Dave Maxfield


- -----------------------------
Tim Moore


- -----------------------------
George Moratis



                                       11

<PAGE>   53


- -----------------------------
Gary Nemirovsky


- -----------------------------
Robert C. Oplinger


- -----------------------------
Steve Pennington


- -----------------------------
Pete Popeck


- -----------------------------
Nancy Green


- -----------------------------
Teresa O'Neill


- -----------------------------
Shirley White


- -----------------------------
Andrea Staertow

                   [Investors' Signatures Appear on Next Page]



                                       12

<PAGE>   54

INVESTORS:

METROCALL, INC.                    AETHER SYSTEMS, INC.

By:                                By:
   ----------------------------      ----------------------------

Name:                              Name:
     --------------------------         -------------------------
Title:                             Title:
      -------------------------          ------------------------


PSINET INC.                        HMTF BRIDGE MC II, LLC


By:                                By:
   ----------------------------      ----------------------------

Name:                              Name:
     --------------------------         -------------------------
Title:                             Title:
      -------------------------          ------------------------


DB CAPITAL INVESTORS, L.P.         ROBERT H. LESSIN
BY: DB CAPITAL PARTNERS, L.P.,     VENTURE CAPITAL LLC
   ITS GENERAL PARTNER
BY: DB CAPITAL PARTNERS, INC.


By:                                By:
   ----------------------------      ----------------------------

Name:                              Name:
     --------------------------         -------------------------
Title:                             Title:
      -------------------------          ------------------------

Exhibits:

Exhibit A - Schedule of Founders
Exhibit B - Schedule of Investors
Exhibit C - Addresses for Notices



                                       13

<PAGE>   55

                                    EXHIBIT A

                              SCHEDULE OF FOUNDERS

<TABLE>
<CAPTION>
- --------------------------------------------------------------
           FOUNDER                           NUMBER OF SHARES
- --------------------------------------------------------------
<S>                                                 <C>
     William L. Collins, III                          615,386
- --------------------------------------------------------------
     Steven D. Jacoby                                 461,538
- --------------------------------------------------------------
     Vincent D. Kelly                                 461,538
- --------------------------------------------------------------
     Thomas Matthews                                  461,538
- --------------------------------------------------------------
     Dick Johnston                                     35,000
- --------------------------------------------------------------
     Francis Martin                                    35,000
- --------------------------------------------------------------
     Ron Aprahamian                                    35,000
- --------------------------------------------------------------
     Royce Yudcoff                                     35,000
- --------------------------------------------------------------
     Harry Brock                                       35,000
- --------------------------------------------------------------
     Jackie Kimzee                                     35,000
- --------------------------------------------------------------
     Max Hopper                                        35,000
- --------------------------------------------------------------
     Ed Jungerman                                      35,000
- --------------------------------------------------------------
     Michael Greene                                    35,000
- --------------------------------------------------------------
     Bonnie K. Culp                                    25,000
- --------------------------------------------------------------
     Randy Forster                                     25,000
- --------------------------------------------------------------
     Albert Gencarella                                 25,000
- --------------------------------------------------------------
     Kenneth Goldstein                                 25,000
- --------------------------------------------------------------
     Steve Marinaro                                    25,000
- --------------------------------------------------------------
     Stan Sech                                         25,000
- --------------------------------------------------------------
     Jeffrey A. Owens                                  25,000
- --------------------------------------------------------------
     Bob Pawa                                          25,000
- --------------------------------------------------------------
     Michael Scanlon                                   25,000
- --------------------------------------------------------------
     Jim Boso                                          25,000
- --------------------------------------------------------------
     Mark S. Dipple                                    25,000
- --------------------------------------------------------------
     Dean Finkenburg                                   25,000
- --------------------------------------------------------------
     Tony Hairston                                     25,000
- --------------------------------------------------------------
     Roman Kozak                                       25,000
- --------------------------------------------------------------
     Pam Mann                                          25,000
- --------------------------------------------------------------
     James McWhirter                                   25,000
- --------------------------------------------------------------
     Robert W. Carpenter                               20,000
- --------------------------------------------------------------
     B. William Caton II                               10,000
- --------------------------------------------------------------
     Robert M Chiatello                                15,000
- --------------------------------------------------------------
     Ellen Crawford                                    10,000
- --------------------------------------------------------------
     Richard D Dewey, Jr.                              10,000
- --------------------------------------------------------------
     Peter Dubois                                      10,000
- --------------------------------------------------------------
     Bill Harrell                                      10,000
- --------------------------------------------------------------
     Kevin Hayes                                       25,000
- --------------------------------------------------------------
     Mack Henderson                                    10,000
- --------------------------------------------------------------
</TABLE>



                                       14
<PAGE>   56

<TABLE>
<CAPTION>
- --------------------------------------------------------------
         FOUNDER                            NUMBER OF SHARES
- --------------------------------------------------------------
<S>                                         <C>
     Bill Jones                                         5,000
- --------------------------------------------------------------
     Rob Griffen                                       10,000
- --------------------------------------------------------------
     Paul J. Liberty                                   10,000
- --------------------------------------------------------------
     Dave Maxfield                                     20,000
- --------------------------------------------------------------
     Tim Moore                                         15,000
- --------------------------------------------------------------
     George Moratis                                    20,000
- --------------------------------------------------------------
     Gary Nemirovsky                                   20,000
- --------------------------------------------------------------
     Robert C. Oplinger                                 5,000
- --------------------------------------------------------------
     Steve Pennington                                  15,000
- --------------------------------------------------------------
     Pete Popeck                                        5,000
- --------------------------------------------------------------
     Nancy Green                                        5,000
- --------------------------------------------------------------
     Teresa O'Neill                                    10,000
- --------------------------------------------------------------
     Shirley White                                      5,000
- --------------------------------------------------------------
     Andrea Staertow                                   20,000
- --------------------------------------------------------------

     TOTAL                                          3,000,000
- --------------------------------------------------------------
</TABLE>



                                       15

<PAGE>   57

                                    EXHIBIT B

                              SCHEDULE OF INVESTORS

<TABLE>
<CAPTION>
- --------------------------------------------------------------
                    INVESTOR                 NUMBER OF SHARES
- --------------------------------------------------------------
<S>                                              <C>
     METROCALL, INC.                                7,500,000
- --------------------------------------------------------------
     AETHER SYSTEMS, INC.                           4,950,000
- --------------------------------------------------------------
     PSINET INC.                                      950,000
- --------------------------------------------------------------
     HMTF BRIDGE MC II, LLC                           950,000
- --------------------------------------------------------------
     DB CAPITAL INVESTORS, L.P.                       400,000
- --------------------------------------------------------------
     ROBERT H. LESSIN VENTURE CAPITAL LLC             250,000
- --------------------------------------------------------------

     TOTAL                                         15,000,000
- --------------------------------------------------------------
</TABLE>



                                       16

<PAGE>   58

                                    EXHIBIT C

                              ADDRESSES FOR NOTICES

INCISCENT, INC.                           ROBERT H. LESSIN VENTURE CAPITAL LLC
6677 Richmond Highway                     c/o Wit Capital
Alexandria, Virginia  2230                6826 Broadway
Attn.: Thomas Matthews                    New York, New York  10003
Fax No.: 703-768-5047                     Fax No.: 212-253-4650

METROCALL, INC.
6677 Richmond Highway
Alexandria, Virginia  22306
Attn.: Vincent D. Kelly
Fax No.: 703-768-5047

AETHER SYSTEMS, INC.
11460 Cronridge Drive
Owings Mills, Maryland  21117
Attn.: Bryan W. Keane
Fax No.: 410-654-6554

PSINET INC.
510 Huntmar Park Drive
Herndon, Virginia  20170
Attn: John Walpuck, Vice President, Corporate Development
Fax No.: 703-476-2983
with a copy to:
Kathleen B. Horne, Senior Vice President and General Counsel
Fax No.: 703- 904-9527

HMTF BRIDGE MC II, LLC
c/o Hicks, Muse, Tate & Furst Incorporated
1325 Avenue of the Americas, 25th Floor
New York, New York  10019
Attn:  Michael Levitt
Fax No.: 212-424-1450

DB CAPITAL INVESTORS, L.P.
c/o DB Capital Partners, Inc.
130 Liberty Street
New York, New York 10006
Attn: Frank Schiff
Fax No.: 212-250-7651



                                       17
<PAGE>   59
                                                                       EXHIBIT H

                                 INCISCENT, INC.

                                VOTING AGREEMENT

     This Voting Agreement (the "Agreement") is made as of the ___ day of
_____________ 2000, by and among Inciscent, Inc., a Delaware corporation (the
"Company"), the individuals listed on Exhibit A to this Agreement (each a
"Founder" and collectively the "Founders"), and the holders of shares of Series
A Preferred Stock listed on Exhibit B to this Agreement (each an "Investor" and
collectively the "Investors").

                                    RECITALS

     The Company and the Investors have entered into a Series A Preferred Stock
Purchase Agreement (the "Purchase Agreement") dated as of February 8, 2000
pursuant to which the Company has agreed to sell to the Investors and the
Investors have agreed to purchase from the Company shares of the Company's
Series A Preferred Stock (the "Series A Preferred Stock"). A condition to the
Investors' obligations under the Purchase Agreement is that the Company, the
Founders and the Investors enter into this Agreement for the purpose of setting
forth the terms and conditions pursuant to which the Investors and the Founders
shall vote their shares of the Company's voting stock in favor of certain
designees to the Company's Board of Directors.

     The Company, the Investors and the Founders each desire to facilitate the
voting arrangements set forth in this Agreement, and the sale and purchase of
shares of Series A Preferred Stock pursuant to the Purchase Agreement, by
agreeing to the terms and conditions set forth herein.

                                    AGREEMENT

     The parties hereby agree as follows:

     1.   BOARD REPRESENTATION.

          (a)  The Company hereby agrees to take such actions as are necessary,
and each of the Founders and Investors agrees to vote his, her or its shares of
the Company's common stock, par value $0.0001 per share (the "Common Stock"),
and Series A Preferred Stock (and any other shares of the capital stock of the
Company over which he, she or it exercises voting control) and take such other
actions as are necessary, so as to elect and thereafter continue in office as
directors of the Company such individuals who may be nominated by each of the
following Investors (with each of the following Investors having the exclusive
right to make nominations as to the number of directorships indicated):

       Metrocall, Inc.            - three, one of whom shall be the Chairman of
                                    the Board
       Aether Systems, Inc.       - two
       HMTF Bridge MC II, LLC     - one
       PSINet Inc.                - one.



                                        1

<PAGE>   60

          (b)  Removal and Substitution of Board Members. The Company hereby
agrees to take such actions as are necessary, and each of the Founders and
Investors agrees to vote his, her or its shares of Common Stock and Series A
Preferred Stock (and any other shares of the capital stock of the Company over
which he, she or it exercises voting control) and take such other actions as are
necessary, for the removal of any director upon the request of the party or
parties designating such director and for the election to the Board of Directors
of a substitute designated by such party.

          (c)  Vacancies on Board of Directors. The Company hereby agrees to
take such actions as are necessary, and each of the Founders and Investors
agrees to vote his, her or its shares of Common Stock and Series A Preferred
Stock (and any other shares of the capital stock of the Company over which he,
she or it exercises voting control) and take such other actions as are
necessary, in such manner as shall be necessary or appropriate to ensure that
any vacancy on the Board of Directors of the Company (occurring for any reason)
shall be filled by the election to the Board of Directors of a replacement
designated by the party or parties who designated the director whose failure to
continue to serve causes the applicable vacancy.

          (d)  Covenants of the Company. The Company agrees to use its best
efforts to ensure that the rights granted hereunder are effective and that the
parties hereto enjoy the benefits thereof. Such actions include, without
limitation, the use of the Company's best efforts to cause the nomination and
election of the directors as provided above. The Company will not, by any
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms to be performed hereunder by the Company, but will at all times in
good faith assist in the carrying out of all of the provisions of this Agreement
and in the taking of all such actions as may be necessary or in order to protect
the rights of the parties hereunder against impairment.

          (e)  Grant of Proxy. Should the provisions of this Agreement be
construed to constitute the granting of proxies, such proxies shall be deemed
coupled with an interest and are irrevocable for the term of this Agreement.

          (f)  Indemnification. The Certificate of Incorporation or Bylaws of
the Company shall at all times provide for the exculpation and indemnification
of the Board of Directors to the fullest extent permitted by the law of the
jurisdiction in which the Company is organized.

     2.   LEGENDS. In addition to any other legends required by law or
agreements between or among the parties, each certificate representing Founders'
or Investor's shares of Common Stock or Series A Preferred Stock shall be
endorsed by the Company with a legend reading as follows:

     "THE SHARES EVIDENCED HEREBY ARE SUBJECT TO A VOTING AGREEMENT BY AND AMONG
     THE COMPANY, THE FOUNDERS AND THE INVESTORS (A COPY OF WHICH MAY BE
     OBTAINED FROM THE COMPANY), AND BY ACCEPTING ANY INTEREST IN SUCH SHARES
     THE PERSON ACCEPTING SUCH INTEREST SHALL BE DEEMED TO AGREE TO AND SHALL
     BECOME BOUND BY ALL THE PROVISIONS OF SAID VOTING AGREEMENT."



                                        2

<PAGE>   61

     3.   NO HEIGHTENED DUTY. Each party hereby acknowledges and agrees that no
fiduciary duty, duty of care, duty of loyalty or other heightened duty will be
created or imposed upon any party to any other party, the Company or any other
stockholder of the Company, by reason of this Agreement and/or any right or
obligation hereunder.

     4.   SPECIFIC PERFORMANCE. The parties hereby acknowledge that it is
impossible to measure in money the damages that will accrue to a party hereto or
to its heirs, personal representatives, or assignees, by reason of a party's
failure to perform its obligations under this Agreement and therefore agree
that, in addition to and without limiting any remedies available at law, each of
the parties hereto will have full equitable remedies available to such party.

     5.   TERMINATION. This Agreement shall terminate in its entirety on the
earlier of (a) consummation of the sale of the Company's Common Stock in a firm
commitment underwritten public offering pursuant to a registration statement
under the Securities Act of 1933, as amended, that results in aggregate cash
proceeds to the Company of at least $20,000,000 (net of underwriting discounts
and commissions), (b) consummation of a transaction in which the Company shall
sell, convey, or otherwise dispose of all or substantially all of its property
or business, or merge into or consolidate with any other corporation (other than
a wholly-owned subsidiary corporation), or effect any other transaction or
series of related transactions in which at least 50% of the voting power of the
Company is disposed of, or (c) mutual agreement in writing by all of the parties
hereto; provided that this Agreement shall not be terminated following a merger
effected solely for the purpose of changing the domicile of the Company.

     6.   AMENDMENTS; WAIVERS. Any term hereof may be amended or waived with the
written consent of the Company, holders of a majority in interest of the Series
A Preferred Stock (calculated on an as converted basis), and holders of a
majority in interest of the Common Stock held by the Founders (or their
respective successors and assigns); provided, however, that any such amendment
or waiver cannot be effected in accordance with this Section 6 if it adversely
affects the rights of any Founder or Investor hereunder or increases the
obligations of any Founder or Investor hereunder unless the affected party
expressly consents, in writing, to such amendment or waiver. Any amendment or
waiver effected in accordance with this Section 6 shall be binding upon the
Company, the holders of Series A Preferred Stock and any holder of the Common
Stock held by the Founders, and each of their respective successors and assigns.

     7.   NOTICES. Any notice required or permitted by this Agreement shall be
in writing and shall be deemed sufficient on the date of delivery, when
delivered personally or by overnight courier or sent by telegram or fax, or
forty-eight (48) hours after being deposited in the U.S. mail, as certified or
registered mail, with postage prepaid, and addressed to the party to be notified
at such party's address as set forth below or on Exhibit C hereto, or as
subsequently modified by written notice.

     8.   SEVERABILITY. Any provision of this Agreement which is invalid or
unenforceable shall be ineffective to the extent of such invalidity or
unenforceability, provided that such invalidity or unenforceability does not
deny any party the material benefits of the transactions for which it has
bargained and such invalidity or unenforceability shall not affect in any way
the remaining provisions hereof.



                                        3

<PAGE>   62

     9.   GOVERNING LAW. This Agreement and all acts and transactions pursuant
hereto and the rights and obligations of the parties hereto shall be governed,
construed and interpreted in accordance with the laws of the State of Delaware,
without giving effect to principles of conflicts of law.

     10.  COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original and all of which
together shall constitute one instrument.

     11.  SUCCESSORS AND ASSIGNS. The terms and conditions of this Agreement
shall inure to the benefit of and be binding upon the respective successors and
assigns of the parties. Nothing in this Agreement, express or implied, is
intended to confer upon any party other than the parties hereto or their
respective successors and assigns any rights, remedies, obligations, or
liabilities under or by reason of this Agreement, except as expressly provided
in this Agreement.

     12.  ENTIRE AGREEMENT. This Agreement constitutes the entire agreement
between the parties hereto pertaining to the subject matter hereof, and any and
all other written or oral agreements relating to the subject matter hereof
existing between the parties hereto are expressly canceled.

                            [Signature Pages Follow]



                                        4

<PAGE>   63

     The parties have executed this Agreement as of the date first written
above.

INCISCENT, INC.

By:
   ------------------------
Name:
     ----------------------------
        (print)
Title:
      ---------------------------

                   [Founders' Signatures Appear on Next Page]



                                        5

<PAGE>   64

FOUNDERS:


- --------------------------
William L. Collins, III


- --------------------------
Steven D. Jacoby


- --------------------------
Vincent D. Kelly


- --------------------------
Thomas Matthews


- --------------------------
Dick Johnston


- --------------------------
Francis Martin


- --------------------------
Ron Aprahamian


- --------------------------
Royce Yudcoff


- --------------------------
Harry Brock


- --------------------------
Jackie Kimzee


- --------------------------
Max Hopper


- --------------------------
Ed Jungerman


- --------------------------
Michael Greene


- --------------------------
Bonnie K. Culp


- --------------------------
Randy Forster



                                        6

<PAGE>   65


- --------------------------
Albert Gencarella


- --------------------------
Kenneth Goldstein


- --------------------------
Steve Marinaro


- --------------------------
Stan Sech


- --------------------------
Jeffrey A. Owens


- --------------------------
Bob Pawa


- --------------------------
Michael Scanlon


- --------------------------
Jim Boso


- --------------------------
Mark S. Dipple


- --------------------------
Dean Finkenburg


- --------------------------
Tony Hairston


- --------------------------
Roman Kozak


- --------------------------
Pam Mann


- --------------------------
James McWhirter


- --------------------------
Robert W. Carpenter



                                        7

<PAGE>   66


- --------------------------
B. William Caton II


- --------------------------
Robert M Chiatello


- --------------------------
Ellen Crawford


- --------------------------
Richard D Dewey, Jr.


- --------------------------
Peter Dubois


- --------------------------
Bill Harrell


- --------------------------
Kevin Hayes


- --------------------------
Mack Henderson


- --------------------------
Bill Jones


- --------------------------
Rob Griffen


- --------------------------
Paul J. Liberty


- --------------------------
Dave Maxfield


- --------------------------
Tim Moore


- --------------------------
George Moratis


- --------------------------
Gary Nemirovsky



                                        8

<PAGE>   67


- --------------------------
Robert C. Oplinger


- --------------------------
Steve Pennington


- --------------------------
Pete Popeck


- --------------------------
Nancy Green


- --------------------------
Teresa O'Neill


- --------------------------
Shirley White


- --------------------------
Andrea Staertow

                   [Investors' Signatures Appear on Next Page]



                                        9

<PAGE>   68

INVESTORS:

METROCALL, INC.                    AETHER SYSTEMS, INC.

By:                                By:
   ----------------------------      ----------------------------

Name:                              Name:
     --------------------------         -------------------------
Title:                             Title:
      -------------------------          ------------------------


PSINET INC.                        HMTF BRIDGE MC II, LLC


By:                                By:
   ----------------------------      ----------------------------

Name:                              Name:
     --------------------------         -------------------------
Title:                             Title:
      -------------------------          ------------------------


DB CAPITAL INVESTORS, L.P.         ROBERT H. LESSIN
BY: DB CAPITAL PARTNERS, L.P.,     VENTURE CAPITAL LLC
   ITS GENERAL PARTNER
BY: DB CAPITAL PARTNERS, INC.


By:                                By:
   ----------------------------      ----------------------------

Name:                              Name:
     --------------------------         -------------------------
Title:                             Title:
      -------------------------          ------------------------

Exhibits:

Exhibit A - Schedule of Founders
Exhibit B - Schedule of Investors
Exhibit C - Addresses



                                       10

<PAGE>   69

                                    EXHIBIT A

                              SCHEDULE OF FOUNDERS

<TABLE>
<CAPTION>
- --------------------------------------------------------------
           FOUNDER                           NUMBER OF SHARES
- --------------------------------------------------------------
<S>                                                 <C>
     William L. Collins, III                          615,386
- --------------------------------------------------------------
     Steven D. Jacoby                                 461,538
- --------------------------------------------------------------
     Vincent D. Kelly                                 461,538
- --------------------------------------------------------------
     Thomas Matthews                                  461,538
- --------------------------------------------------------------
     Dick Johnston                                     35,000
- --------------------------------------------------------------
     Francis Martin                                    35,000
- --------------------------------------------------------------
     Ron Aprahamian                                    35,000
- --------------------------------------------------------------
     Royce Yudcoff                                     35,000
- --------------------------------------------------------------
     Harry Brock                                       35,000
- --------------------------------------------------------------
     Jackie Kimzee                                     35,000
- --------------------------------------------------------------
     Max Hopper                                        35,000
- --------------------------------------------------------------
     Ed Jungerman                                      35,000
- --------------------------------------------------------------
     Michael Greene                                    35,000
- --------------------------------------------------------------
     Bonnie K. Culp                                    25,000
- --------------------------------------------------------------
     Randy Forster                                     25,000
- --------------------------------------------------------------
     Albert Gencarella                                 25,000
- --------------------------------------------------------------
     Kenneth Goldstein                                 25,000
- --------------------------------------------------------------
     Steve Marinaro                                    25,000
- --------------------------------------------------------------
     Stan Sech                                         25,000
- --------------------------------------------------------------
     Jeffrey A. Owens                                  25,000
- --------------------------------------------------------------
     Bob Pawa                                          25,000
- --------------------------------------------------------------
     Michael Scanlon                                   25,000
- --------------------------------------------------------------
     Jim Boso                                          25,000
- --------------------------------------------------------------
     Mark S. Dipple                                    25,000
- --------------------------------------------------------------
     Dean Finkenburg                                   25,000
- --------------------------------------------------------------
     Tony Hairston                                     25,000
- --------------------------------------------------------------
     Roman Kozak                                       25,000
- --------------------------------------------------------------
     Pam Mann                                          25,000
- --------------------------------------------------------------
     James McWhirter                                   25,000
- --------------------------------------------------------------
     Robert W. Carpenter                               20,000
- --------------------------------------------------------------
     B. William Caton II                               10,000
- --------------------------------------------------------------
     Robert M Chiatello                                15,000
- --------------------------------------------------------------
     Ellen Crawford                                    10,000
- --------------------------------------------------------------
     Richard D Dewey, Jr.                              10,000
- --------------------------------------------------------------
     Peter Dubois                                      10,000
- --------------------------------------------------------------
     Bill Harrell                                      10,000
- --------------------------------------------------------------
     Kevin Hayes                                       25,000
- --------------------------------------------------------------
     Mack Henderson                                    10,000
- --------------------------------------------------------------
     Bill Jones                                         5,000
- --------------------------------------------------------------
</TABLE>



                                       11

<PAGE>   70

<TABLE>
<CAPTION>
- --------------------------------------------------------------
         FOUNDER                            NUMBER OF SHARES
- --------------------------------------------------------------
<S>                                         <C>
     Rob Griffen                                       10,000
- --------------------------------------------------------------
     Paul J. Liberty                                   10,000
- --------------------------------------------------------------
     Dave Maxfield                                     20,000
- --------------------------------------------------------------
     Tim Moore                                         15,000
- --------------------------------------------------------------
     George Moratis                                    20,000
- --------------------------------------------------------------
     Gary Nemirovsky                                   20,000
- --------------------------------------------------------------
     Robert C. Oplinger                                 5,000
- --------------------------------------------------------------
     Steve Pennington                                  15,000
- --------------------------------------------------------------
     Pete Popeck                                        5,000
- --------------------------------------------------------------
     Nancy Green                                        5,000
- --------------------------------------------------------------
     Teresa O'Neill                                    10,000
- --------------------------------------------------------------
     Shirley White                                      5,000
- --------------------------------------------------------------
     Andrea Staertow                                   20,000
- --------------------------------------------------------------

     TOTAL                                          3,000,000
- --------------------------------------------------------------
</TABLE>



                                       12

<PAGE>   71

                                   EXHIBIT B
                             SCHEDULE OF INVESTORS
<TABLE>
<CAPTION>
- --------------------------------------------------------------
                    INVESTOR                 NUMBER OF SHARES
- --------------------------------------------------------------
<S>                                              <C>
     METROCALL, INC.                                7,500,000
- --------------------------------------------------------------
     AETHER SYSTEMS, INC.                           4,950,000
- --------------------------------------------------------------
     PSINET INC.                                      950,000
- --------------------------------------------------------------
     HMTF BRIDGE MC II, LLC                           950,000
- --------------------------------------------------------------
     DB CAPITAL INVESTORS, L.P.                       400,000
- --------------------------------------------------------------
     ROBERT H. LESSIN VENTURE CAPITAL LLC             250,000
- --------------------------------------------------------------

     TOTAL                                         15,000,000
- --------------------------------------------------------------
</TABLE>



                                       13


<PAGE>   72

                                    EXHIBIT C

                              ADDRESSES FOR NOTICES

INCISCENT, INC.                          ROBERT H. LESSIN VENTURE CAPITAL LLC
6677 Richmond Highway                    c/o Wit Capital
Alexandria, Virginia  2230               6826 Broadway
Attn.: Thomas Matthews                   New York, New York  10003
Fax No.: 703-768-5047                    Fax No.: 212-253-4650

METROCALL, INC.
6677 Richmond Highway
Alexandria, Virginia  22306
Attn.: Vincent D. Kelly
Fax No.: 703-768-5047

AETHER SYSTEMS, INC.
11460 Cronridge Drive
Owings Mills, Maryland  21117
Attn.: Bryan W. Keane
Fax No.: 410-654-6554

PSINET INC.
510 Huntmar Park Drive
Herndon, Virginia  20170
Attn: John Walpuck, Vice President, Corporate Development
Fax No.: 703-476-2983
with a copy to:
Kathleen B. Horne, Senior Vice President and General Counsel
Fax No.: 703- 904-9527

HMTF BRIDGE MC II, LLC
c/o Hicks, Muse, Tate & Furst Incorporated
1325 Avenue of the Americas, 25th Floor
New York, New York  10019
Attn:  Michael Levitt
Fax No.: 212-424-1450

DB CAPITAL INVESTORS, L.P.
c/o DB Capital Partners, Inc.
130 Liberty Street
New York, New York 10006
Attn: Frank Schiff
Fax No.: 212-250-7651



                                       14

<PAGE>   1
                                                                   EXHIBIT 10.26

                                                         STRICTLY CONFIDENTIAL

                                    Agreement

                                     BETWEEN

                      NATIONAL DISCOUNT BROKERS CORPORATION
                                       AND

                         AETHER SYSTEMS INC. ("AETHER")

This Agreement (the "Agreement") is effective as of November 4th, 1999 (the
"Effective Date"), by and between National Discount Brokers Corporation, a New
York corporation ("National Discount Brokers"), having its principal place of
business at, New York, New York and Aether Systems, Inc., a Delaware corporation
("Aether"), having its principal place of business at 11460 Cronridge Drive,
Suite 160, Owings Mills, Maryland 21117.

National Discount Brokers Corporation and Aether hereby enter into a definitive
and binding contractual agreement for purposes of the development,
implementation, sale and support of a wireless financial data access and trading
product for sale to persons who have brokerage accounts with National Discount
Brokers (the "Subscribers") and who reside within the United States of America
hereto (the "Territory"). The product which is described in Schedule A hereto
shall for the purposes of the Agreement be known as "National Discount Brokers
Wireless Product" (the "Product") and would provide the Subscribers with mobile
device access to real-time National Discount Brokers' account, trading and
financial market information. The Product would initially source data from
National Discount Brokers host computer systems along with market data and news
from Reuters SelectFeed Plus platform, or such additional or replacement feeds
product(s) as mutually agreed to by National Discount Brokers and Aether (the
"National Discount Brokers Service").

1 Term.

The Agreement shall take effect on the Effective Date, continue for two years,
and shall automatically renew thereafter for additional one year terms, unless,
prior to any additional one year term, either party provides the other party
sixty (60) days' prior written notice of termination. Ninety(90) days prior to
the termination or expiration of the Agreement, the parties agree to negotiate
in good faith the terms and conditions of a licensing agreement for National
Discount Brokers to use Aether's intellectual property relating to the National
Discount Brokers Service and the Product.

2 RESPONSIBILITIES OF AETHER.

System Development
a)     Aether shall be responsible for all development activity associated with
the wireless data system (the "System") necessary for operation and delivery of
the Product including, but not limited to application software development,
network development and integration.

Software Development
b)     Aether shall be responsible for all custom software development required
to support the Product including, but not limited to host system interface,
application development and network interface.

Network Operations
c)     Aether shall manage, operate and maintain the System in accordance with
specifications and service levels to be agreed to by the parties hereto, which
shall include, but not be limited to, network management, operational
management, and the day-to-day operating environment.


<PAGE>   2



Hardware
d)     Aether shall initiate and maintain relationships with all hardware
vendors on favorable terms. Hardware selected shall meet the specifications to
be agreed upon by the parties hereto. Aether shall arrange for maintenance and
repair of the same, and will provide the National Discount Brokers Service in
accordance with standards to be agreed upon by the parties hereto.

Billing/Order Entry
e)     Aether shall develop, implement and maintain order-entry and billing
systems for the Product. These systems shall provide administration,
permissioning and depermissioning.

Customer Support Vendor Relations
f)     Aether shall develop, implement and manage customer support including but
not limited to, 8:30 AM -- 8:00 PM EST Monday through Friday, and shall manage
and coordinate relationships with third party suppliers such as airtime
providers and hardware vendors. Aether agrees to implement 24/7 customer service
within 6 months from execution of the Agreement.

Third Party Agreements
g)     Aether shall obtain any and all licenses and consents, and enter into and
comply with any applicable third party agreements, as may be necessary to
fulfill its obligations under the Agreement, including but not limited to
Exchange Agreements with the New York Stock Exchange, American Stock Exchange
and the Nasdaq

Subscriber Exchange Fees
h)     Aether shall be responsible for obtaining any exchange fees associated
with the receipt of real time market data on a Subscriber basis from the
individual Subscribers.

Marketing Campaign
i)     Aether Systems shall commit to investing a minimum of $500,000 in
       an advertising campaign to support the launch of the Product by
       National Discount Brokers. The $500,000 may include the value of
       advertising provided by various Aether associates. Aether will also
       use its best efforts to obtain additional advertising dollars for
       this launch through is strong association with carriers and
       hardware manufacturers.

3  RESPONSIBILITIES OF NATIONAL DISCOUNT BROKERS.

Exclusivity
a)     National Discount Brokers agrees that Aether shall be its exclusive
       provider of the Product to National Discount Brokers for the term of the
       Agreement.
Should hardware devices and or transport protocols emerge during the
term of the Agreement that may prove attractive to National Discount Brokers or
its customers, National Discount Brokers will so notify Aether in writing (the
"Competition Notice"). Aether shall have the right of first refusal to provide
said device or services (a "Competitive Service"), on terms which are the same
or better than those available to National Discount Brokers or its competitors
for the Competitive Service. National Discount Brokers shall obtain an estimate
if possible from any provider of the Competitive Service. Aether would then
provide National Discount Brokers an estimate to provide the service or device
which is the same as the Competitive Service within thirty days of Aether's
receipt of the Competitive Notice. If Aether's price and terms for the
Competitive Service are the same or better than that of the provider of the
Competitive Service to National Discount Brokers, then National Discount Brokers
shall select Aether to provide the Competitive Service. If Aether fails to
deliver to National Discount Brokers the Competitive Service at the price and
terms which are the same as or better than those made available to National
Discount Brokers or its competitors within the thirty day period after the
Competitive Notice, the provisions of this paragraph 3(a) shall be terminated
and Aether's right of first refusal shall be terminated.


<PAGE>   3



Tools and Documentation

a)     National Discount Brokers shall provide to Aether , at no charge, all
required software, tools, and documentation required to permit the Product
through the communications structure of Aether to communicate with the computer
system of National Discount Brokers.

DataFeeds
b)     National Discount Brokers shall grant to Aether a non-exclusive,
non-transferable license to receive and distribute the National Discount Brokers
Service information through the Product only within the Territory. Aether shall
receive the National Discount Brokers Service during the term of the Agreement
without payment of subscription fees and installation costs.

Telecommunication Equipment
c)     National Discount Brokers shall provide all communication lines and
equipment required to provide for communication from the National Discount
Brokers computer to the Aether computer and visa versa. National Discount
Brokers shall transmit the National Discount Brokers Service to Aether free of
any telecommunication charges. National Discount Brokers shall maintain a
development, environment to permit the testing of new features on the Product
without interruption of the National Discount Brokers Service.

Sales and Marketing
g)   In consideration of Aether having developed the System at its own
     expense and its undertaking not to seek compensation for said development
     costs from National Discount Brokers, National Discount Brokers commits
     itself to a marketing and advertising campaign for the product that is
     representative of its normal business practices for similar products.
     National Discount Brokers shall commit itself to soliciting news, and print
     media attention to the impending Product release and subsequent to that
     release date. National Discount Brokers shall define and document a
     marketing and sales plan illustrating a commitment of no less than $500,000
     over the course of the first year to the Product launch. This plan shall be
     developed within the first month after activation of the Agreement. It is
     agreed that National Discount Brokers will have the final approval on the
     creative copy and ad placement. National Discount Brokers will display at a
     minimum the Aether Logo and the phrase powered and engineered by Aether
     Systems Inc. National Discount Brokers' commitment under this paragraph (d)
     during the term of the Agreement shall not exceed $500,000.

Product Launch Plan
e)     National Discount Brokers shall budget, develop and implement marketing
and sales plans which shall include, but not be limited to, product launch
schedules, beta test program Subscriber identification, beta testing, marketing
materials, sales projections, sales force training, and public relations
releases. The plan shall be developed as part of an agreed to Product
development plan and schedules.

Future Requirements
f)     National Discount Brokers shall cooperate in the identification and the
development of mutually agreed to Product enhancements.

Trading Fees
g)     National Discount Brokers shall be responsible for any trading fees
associated with the Product.

h)     National Discount Brokers shall as part of its normal course of
       promotion for products and services, add the information regarding
       the Product to its internet site in the manner it determines in its
       sole discretion.. Aether shall provide a companion web site for
       Product information, Product ordering, and customer support.


<PAGE>   4
4            COOPERATION.

Roles and Responsibilities
a)     National Discount Brokers and Aether agree to reasonably cooperate with
one another to facilitate the achievement of their respective responsibilities,
and to document, as necessary, all relevant plans, schedules, models and
procedures mentioned above. Aether and National Discount Brokers shall assign a
project manager for the term of the Agreement.

Future Development
b)     All upgrades, modifications, enhancements to the Product, the System, the
Software, National Discount Brokers Service and the use of other devices shall
be mutually agreed upon in writing by the parties hereto before any work
commences. The parties hereto shall decide, on a case by case basis, the source
of funds for such upgrades, modifications and enhancements. Aether agrees to
provide upgrades of the Product and the System to National Discount Brokers and
its Subscribers on the same terms and conditions as such enhancements are made
available to other third parties.

Hardware Purchase
c)     National Discount Brokers shall retain the right upon (90) day written
notice to contract for and purchase all hardware for the Product for sale to
Subscribers. National Discount Brokers shall assign any applicable warranties
from hardware vendors to the Subscribers.

Insurance
d)     Should National Discount Brokers execute its right to purchase hardware
during the term, National Discount Brokers will maintain sufficient insurance
coverage for the inventory of hardware stored at Aether to recover the value of
the hardware in the event of damage, loss or theft. Aether shall take reasonable
commercial precautions to safeguard the hardware inventory stored by it.

Training
e)     National Discount Brokers and Aether will jointly work towards a plan
whereby both parties hereto may participate where appropriate in an onsite
training session with the National Discount Brokers customer service
organization. National Discount Brokers shall undertake to establish an ongoing
training cycle in accordance with National Discount Brokers normal practices.
Aether shall also provide phone support to National Discount Brokers for
training purposes.

Devices
f)     National Discount Brokers and Aether agree to develop this application on
Palm and Windows CE devices. Aether and National Discount Brokers shall decide,
on a case by case basis, the source of funds for such new devices, product
upgrades, system modifications and application enhancements.

Subscriber/ User Manual
g)     Aether will where practical supply National Discount Brokers with a user
guide for Subscribers in sufficient quantities so as to meet demand.



5             OWNERSHIP.

      Software
a)     National Discount Brokers and Aether agree that the System along with all
source code required to provide financial information to Subcribers hardware
device ("the Software") shall be the property of Aether ; provided however any
software that resides on computer or othe hardware owned, leased or used by
National Discount Brokers shall not be deemed to be Software.

Trademark
b)     National Discount Brokers and Aether agree to "brand" the Product which
trademark shall be the property of National Discount Brokers. National Discount
Brokers has the responsibility for any and all legal costs associated with
trademarking the name.


<PAGE>   5
6             FINANCIALS.

Monthly Fees
a)     In consideration of Aether being responsible for managing the Subscriber
provisioning, permissioning, activation, customer service, network and systems
management, technical support, software development, billing, collections,
managing carrier relationships, and managing airtime, Aether will charge a
monthly fee to Subscribers inclusive of the above mentioned items for $69.00 per
month. Aether will also bundle much of its current financial news service
("MarketClip(TM)") functionality along with email and internet access per its
ownership in AirWeb Corporation doing business as Opensky into the National
Discount Brokers application free of any additional fees.

Hardware Costs
b)     In consideration of Aether having developed the Product in accordance
with National Discount Brokers requirements and choice of platform delivery
mechanisms, Aether shall charge the Subscribers according to the current market
price of the device(s).

Aether shall undertake (within 30 days of written notification) to reduce the
price of Subscriber hardware to a price not greater than the vendor's published
price schedule that reflects a deduction in price for the aforementioned
hardware models.

New Hardware Models
Aether shall advise National Discount Brokers from time to time as to the
upcoming release of new hardware models and advise National Discount Brokers as
to the efficacy of adopting the new model as the defacto hardware for
Subscribers.

Subscriber Term
Each Subscriber shall enter into a one year agreement for the National Discount
Brokers Service. Should the Subscriber at any time after an initial 15 day trial
decide to cancel the National Discount Brokers Service the Subscriber shall be
held accountable for payment of 75% of the remaining contract fees.

Subscriber Exchange Fees
c.)     It is understood that exchange fees associated with the receiving of
real time market data shall be paid by the Subscriber and are in addition to the
monthly fees.

Trading Fees
d)     National Discount Brokers shall be responsible for any trading fees other
than payments for real time quotes associated with subscribers using the System.
Activation
h)     Aether shall be entitled to receive a one time activation and
       handling fee of $69.00 per new Subscriber to be paid by the Subscriber.
i)     Aether agrees that Subscribers will be entitled to receive and will
       receive the Product on the best terms and conditions, including the
       monthly service charge, that Aether makes the Product (or similar
       device and service) available to other persons from time to time.
       The foregoing most favored nation clause shall not apply to short
       term introductory programs of Aether or where the functionality or
       level of service offered is materially different
j)     Aether and National Discount Broker agree to jointly work on
       developing a lower price point wireless product offering for NDB
       customers. During the first month of performance of this Agreement,
       the parties shall establish a plan encompassing various hardware
       and software solutions that will incorporate a lower price point
       product being made available to National Discount Broker customers.
       (It is understood that a lower price point product offering will
       likely necessitate having reduced functionality, usage and response
       limitations for the user.

<PAGE>   6
k)     The parties shall mutually agree to the plan to develop the low cost
       solution referred to in the above paragraph (j). After the plan is
       developed, the parties shall pursue sufficient funding to implement the
       plan.

7           CONFIDENTIALITY.

a)     Each party hereto acknowledges that it has received, and will during the
       term of the Agreement, receive confidential or proprietary information
       regarding the business or products of the other party hereto. Each party
       hereto will maintain the confidentiality of such information, provided
       that it is designated in writing as confidential, proprietary, or marked
       with words of similar import, or if orally conveyed, is reduced to
       writing and delivered to the receiving party by the disclosing party
       within 10 days of oral conveyance. Each party hereto agrees that if the
       proposed transaction is not consummated for any reason, it will return to
       the other party hereto all confidential material or information without
       retaining any copies thereof.

b)           Confidential information shall not include information which:

             i)          at or prior to the time of disclosure by the disclosing
party was known to the receiving party;
             ii) at or after the time of disclosure by the disclosing party
becomes generally available to the public other than through any act or omission
on the receiving party's part;
             iii) is developed by the receiving party independent of any
confidential information it receives from the disclosing party;
             iv) the receiving party receives from a third party free to make
such disclosure without breach of any legal obligation; or
              v) is required to be disclosed pursuant to any order, subpoena or
document discovery request.

8           EXCLUSIVITY.

             Aether from the effective date of the Agreement shall not license
any rights to the executable software and source code that constitutes the
National Discount Brokers specific back office trading and account management
interfaces, to any competitor of National Discount Brokers for the purpose of
the wireless transmission of National Discount Brokers information. This
capability is embodied and implemented within a single software library, titled,
National Discount Brokers.dll. It is understood that Aether having bundled
MarketClip(TM) and Opensky functionality into the Product that functionality
shall not be considered part of this exclusivity clause. Aether has retained
full rights to the MarketClip and Opensky products and shall NOT be bound or
restricted in its ability to market the product to National Discount Brokers
competitors. It is also understood that Aether has utilized Aether's proprietary
Aether Intelligent Messaging executable software components ("AIM(TM)") and
source code(AIM(TM)) in the Product that AIM(TM) shall not be considered part of
this exclusivity clause. Aether has retained full rights to the AIM(TM) product
and shall NOT be bound or restricted in its ability to market the Product to
National Discount Brokers competitors.

9           LIABILITY

Aether shall not be liable for any entered order, trade account or position
inquiry by a Subscriber or user of the device that results in financial loss or
injury to the respective client or holder of said account.

NEITHER PARTY HERETO SHALL BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT
AND/OR, CONSEQUENTIAL DAMAGES OF ANY KIND, RESULTING FROM EITHER PARTY'S
PERFORMANCE OR FAILURE TO PERFORM PURSUANT TO THE TERMS OF THE AGREEMENT OR
RESULTING FROM THE FURNISHING, PERFORMANCE OR USE OR LOSS OF ANY LICENSED
PRODUCTS OR OTHER MATERIALS DELIVERED TO NATIONAL DISCOUNT BROKERS THEREUNDER,
INCLUDING WITHOUT LIMITATION ANY INTERRUPTION OF BUSINESS, WHETHER RESULTING
FROM BREACH OF CONTRACT OR BREACH OF WARRANTY, EVEN IF THE PARTIES HERETO HAVE
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

<PAGE>   7




10     PRESS RELEASES.

Neither Aether nor National Discount Brokers or their respective affiliates
shall issue any press release or make any other public statement relating to the
Agreement unless required by law, regulation, court order or the rules of any
applicable stock exchange or regulatory authority or approved in writing by the
other party.

National Discount Brokers agrees to make press releases and public relations
announcements of its impending release of the National Discount Brokers Wireless
Trading System application upon completion of its internal QA cycle. National
Discount Brokers also acknowledges that Aether may make certain statements as
the relationship at its forthcoming IPO roadshow. National Discount Brokers may
at its discretion choose to have Aether undertake to coordinate that effort on
its behalf subject to any National Discount Brokers internal approval processes.

11     TERMINATION.

a)     Termination for Breach. If a party (the "Defaulting Party") is in
material breach of or default under this Agreement, and the Defaulting Party
does not remedy that breach or default within thirty (30) calendar days after
receipt from the other party of written notice of that default or breach, the
other party shall after the expiration of such thirty (30) calendar day period
have the right to terminate this Agreement unless the Defaulting Party has
commenced steps to remedy such breach or default and effects a cure within
thirty (30) days of receipt of the default notice.

Termination in Event of Bankruptcy. Either party may terminate the Agreement at
any time by written notice in the event that the other: (i) files a voluntary
petition in bankruptcy or under any similar insolvency law; (ii) makes an
assignment for the benefit of creditors; (iii) has filed against it any
involuntary petition in bankruptcy or under any similar insolvency law if any
such petition is not dismissed within sixty (60) days after filing; or (iv) has
a receiver appointed for, or a levy or attachment made against, substantially
all of its assets, if any such petition is not dismissed or such receiver or
levy or attachment is not discharged within sixty (60) days after the filing or
appointment.

12)    Assignment

Notwithstanding any other terms of the Agreement, National Discount Brokers
may, subject to Aether's prior consent which consent will be not unreasonably
withheld, transfer the Agreement to its parent organization National Discount
Brokers Group, Inc. and hereby agrees to provide Aether reasonable notice of
any such transfer. Aether may assign the Agreement to any successor to its
business

13)    Governing Law

The Agreement shall be governed by New York law without regard to conflicts of
law principle

NATIONAL DISCOUNT BROKERS CORPORATION              AETHER SYSTEM INC.

/s/ SAMIR SHAH                             /s/ DAVID S. OROS
- -------------------------------------      -----------------------------------
              Signature                                 Signature

SAMIR SHAH CO-CHIEF OPERATING OFFICER        DAVID S. OROS   PRESIDENT/CEO
- -------------------------------------      -----------------------------------
      Name and Title (printed)                   Name and Title (printed)

               11/4/99                                   11/8/99
- -------------------------------------      -----------------------------------
                Date                                       Date




<PAGE>   8
                                  SCHEDULE "A"

          "The Product" shall be identified as any real-time market and delayed
          data/news information and or pertinent brokerage account information
          that can be delivered wirelessly between NDB and their customers(s)
          and from customer(s) to NDB through use of the following hardware
          device(s):

          Palm Devices
          CE Devices
          RIMM Pagers
          WAP (wireless application protocol) enabled phones
          VISOR Devices

           *DOES NOT INCLUDE NDB IVR

               /s/ Samir Shah 11/4/99
             Co-Chief Operating Officer

<PAGE>   1
                                                                   EXHIBIT 10.27
                         RESPONSE SERVICES CENTER, LLC

                             DEVELOPMENT AGREEMENT

     This Development Agreement ("Agreement") is made and entered into as of the
12th day of January 2000, by and between RESPONSE SERVICES CENTER, LLC a
Delaware limited liability company ("RESPONSE"), with its principal place of
business located at 1099 Winterson Road, Linthicum, Maryland 21090 and AETHER
SYSTEMS INCORPORATED, ("Aether"), whose principal place of business is located
at 11460 Cronridge Drive, Suite 106, Owings Mills, Maryland 21117.

                                  WITNESSETH:

     WHEREAS, Aether has expertise in particular areas relevant to the business
RESPONSE is engaged in, and

     WHEREAS, Aether desires to preform system architecture, design, development
and testing of certain software and computer systems for RESPONSE that draw upon
such expertise; as set forth in the Aether Technologies Statement of Work
(SOW) attached as Exhibit A and the Aether Proposal For Response Center System
Development (the Proposal) attached as Exhibit B.

     WHEREAS, RESPONSE desires to engage Aether to perform the services and
deliver the work product specified in the Proposal.

     NOW THEREFORE, in consideration of the mutual promises and covenants herein
contained, and other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, and intending to be legally bound
hereby, the parties hereto agree as follows:

ARTICLE I - SCOPE

     Pursuant to the terms and conditions of this Agreement, Aether shall
perform system architecture, and software design and development tasks as
specified in the Statement of Work (SOW) which is attached as Exhibit A and is
hereby incorporated as part of this Agreement, by reference.

ARTICLE II - DEFINITIONS

     (a)      RESPONSE Software: Any and all computer files developed by Aether
and/or delivered to RESPONSE as part of this Agreement, including but not
limited to: source, object, and/or executable code, build files, script files,
configuration files, and libraries.
<PAGE>   2
     (b)     Aether Proposal: Refers to the Aether Technologies Proposal for
Response Center System Development submitted to RESPONSE on May 28,1999 and
incorporated as Exhibit B

     (c)     Statement of Work (SOW): Refers to the description of
deliverables due from Aether to RESPONSE under the Proposal and incorporated as
Exhibit A.

     (d)     Aether Software: Software developed and/or owned by Aether,
prior to this Agreement, which may be utilized in support of the SOW but
which has not been developed or acquired by Aether exclusively for the purposes
of this Agreement.

ARTICLE III -  CONSIDERATION

     (a)     In return for compliance with all the requirements of this
Agreement, Aether shall be entitled to receive from RESPONSE $1,082,580 for the
services rendered by Aether hereunder in accordance with the milestone schedule
set forth below.

     (b)     Without limiting the obligation of Aether to comply with all
requirements of this Agreement, Aether shall be entitled to receive milestone
payments as set forth in the Proposal and in Article XIII, Project Phases.

     (c)     The prices set forth herein do not include federal, state or local
sales or use taxes. RESPONSE shall be liable for the payment of any such taxes.
Aether shall list separately on its invoices any such tax lawfully applicable
to the goods sold or licensed or the services rendered hereunder and payable
by RESPONSE. In no event shall RESPONSE be liable for the payment of any United
States or foreign federal, state or local income taxes imposed on Aether in
connection with the performance of the services hereunder.

ARTICLE IV -INVOICING

      Aether shall present an invoice, for milestone events set forth in the
Proposal, certifying on each invoice the completion of the milestone and/or
delivery of the associated deliverable item. Aether will list on the invoice
resource charges by named individual. Payments by RESPONSE for the Services
rendered shall be due upon presentation and acceptance of the deliverables as
specified in the proposal and shall be made within 30 days of receipt of an
invoice submitted by Aether - 2% of Net for payment within 15 days.

ARTICLE V - TITLE TO WORK PRODUCT

     (a)     RESPONSE shall receive and retain all right, title, and
intellectual property rights associated with or pertaining to the RESPONSE
Software produced by Aether or delivered to RESPONSE in accordance with this
Agreement, unless otherwise agreed to.

                                       2
<PAGE>   3

    (b)   Title to the physical product or the media on which the Software is
provided or delivered to RESPONSE under this Agreement shall pass to RESPONSE
on final acceptance of the Software by RESPONSE at RESPONSE's Linthicum,
Maryland location. Aether agrees to execute and deliver to RESPONSE all
instruments required to evidence such title to RESPONSE.

    (c)   Aether hereby irrevocably assigns to RESPONSE all right, title and
interest in and to all inventions and discoveries, whether or not patentable and
whether or not reduced to practice, and all other work product of any nature,
whether or not copyrightable, made, conceived or authored by Aether in the
course of performing the Services or any other work under this Agreement and all
tangible embodiments of the foregoing ("Work Product") and all patents,
copyrights, trademarks, trade secrets, and all other intellectual property
rights therein and any extensions and renewals thereof. Aether shall promptly
furnish RESPONSE with complete information with respect to all Work Product
whenever made, conceived or authored by Aether. All copyrightable Work Product
created by Aether in the course of performing the Services or any other work
under this Agreement shall be deemed to be a "work made for hire" in accordance
with 17 U.S.C. Section 101 belonging exclusively to RESPONSE. RESPONSE shall
have the exclusive right to obtain and hold solely in its own name all patents,
copyrights, registrations, trademark registrations, trade secrets and other such
protection for the Work Product as may be appropriate to the subject matter, and
any extensions or renewals therof. Aether shall provide RESPONSE, and any person
designated by RESPONSE, all reasonably necessary cooperation in connection with
RESPONSE's perfection of its patent, trademark, copyright, trade secret and
other rights in the Work Product and RESPONSE's ownership thereof, including
without limitation signing all documents reasonably requested by RESPONSE both
before and after the termination of this Agreement.

ARTICLE VI-INTELLECTUAL PROPERTY INDEMNIFICATION.


    (a)   Aether hereby represents and warrants that the RESPONSE Software does
          not violate or infringe upon any worldwide copyright or trade secret
          of any third party.

    (b)   RESPONSE shall notify Aether of any claim, action or suit against
          RESPONSE arising out of the sublicensing of the Software or the
          alleged infringement by the Software of any trade secrets, patents, or
          copyright of any third party. Aether will indemnify RESPONSE against
          and hold RESPONSE harmless from any and all loss, damage or liability
          assessed against RESPONSE, or incurred by RESPONSE, arising out of or
          in connection with any claim that the Software (1) infringes a patent
          or copyright owned by a third party, or (2) constitutes
          misappropriation of a trade secret; provided, however (i) that
          RESPONSE notifies Aether in writing, within 30 (thirty) days of
          receipt, that any such claim has been brought, (ii) that Aether has
          the right to assume the defense of such claim, with


                                       3
<PAGE>   4


          counsel selected by Aether, (iii) that Aether receives RESPONSE's full
          and complete cooperation in the defense of such claim, at Aether's
          expense, and (iv) that Aether shall have the right to settle such
          claim and/or procure the right to continue the manufacture and
          sublicensing of the Software as contemplated hereunder, and/or modify
          the Software in such a fashion as to eliminate any infringement and
          misappropriation and thereby discharge its obligations hereunder.

    (c)   Aether shall have no obligation hereunder with respect to any
          proceeding or claim of infringement based on RESPONSE'S modification
          of the materials provided by Aether hereunder or the combination,
          operation or use of such materials with program(s) not furnished by
          Aether, if such infringement claim would have been avoided in the
          absence of such modification, combination or operation or use with
          program(s) not furnished by Aether.


ARTICLE VII-AETHER REPRESENTATIONS AND WARRANTIES

(a) Aether represents and warrants that:

    (i) title to any physical product delivered to RESPONSE under this Agreement
    shall be good, marketable, rightfully conveyed and shall be delivered free
    and clear of all liens, encumbrances, pledges or other interests whatsoever,
    except for the continuing ownership by Aether of its intellectual property
    contained in Aether Software;

    (ii) it has all necessary permission, approval and authorization to render
    the Services or utilize any intellectual property rights of any third party
    which may be included in Aether Software, and Aether has the right to grant
    to RESPONSE the rights to the RESPONSE Software as set forth herein;

    (iii) the Services shall comply in all material respects with the
    requirements of this Agreement and shall be performed in a workmanlike
    manner, and rendered in a professional and competent manner by Aether;

    (iv) the Services and the delivered or provided software, to include Aether
    Software, including third party software (to include operating systems, GIS
    software and database software) and the RESPONSE Software, do not and will
    not infringe upon and patents, trade secret, copyright or other intellectual
    property rights of any third party, and

    (v) it shall comply with all applicable governmental laws, rules, and
    regulations.

ARTICLE VIII-LIMITATION OF LIABILITY

                                       4
<PAGE>   5
     EXCEPT AS TO CLAIMS FOR INDEMNIFICATION ARISING UNDER ARTICLE VI HEREOF,
IN NO EVENT SHALL AETHER'S LIABILITY TO RESPONSE EXCEED THE AMOUNT OF
CONSIDERATION IN ARTICLE III PARAGRAPH A OF THIS AGREEMENT. NOTWITHSTANDING
ANYTHING CONTAINED HEREIN TO THE CONTRARY, IN NO EVENT SHALL EITHER PARTY HAVE
ANY OBLIGATION, LIABILITY, RIGHT, CLAIM OR REMEDY AGAINST THE OTHER UNDER THIS
AGREEMENT FOR LOSS OF USE, REVENUE OR PROFIT OR FOR ANY OTHER INDIRECT,
INCIDENTAL OR CONSEQUENTIAL DAMAGES.


ARTICLE IX - TERMINATION

     (a)  The following events shall constitute an event of default by Aether
under this Agreement (an "Aether Event of Default"):

          (i)    Aether fails to complete a milestone event within 10 days of
     the milestone due date set forth in Section 3(b), as such section may be
     amended by mutual agreement of the parties;

          (ii)   Aether shall fail to observe or perform any of its covenants or
     agreements contained in this Agreement and such failure remains uncured for
     a period of 10 days after receipt by Aether of written notice from RESPONSE
     of such failure;

          (iii)  Aether shall (A) make an assignment for the benefit of
     creditors, (B) file a petition in bankruptcy, (C) be adjudicated insolvent
     or bankrupt, (D) petition or apply to any tribunal for any receiver or for
     any trustee for it under any reorganization, arrangement, readjustment of
     debt, dissolution or liquidation law or statute or (E) have commenced
     against it any such proceeding or an order for relief shall be entered
     that remains undismissed for a period of 60 days Aether by any act
     indicates its consent to, approval of, or acquiescence in, any such
     proceeding, order for relief or the appointment of any receiver of or any
     trustee for it or suffers any such receivership or trusteeship to continue
     undischarged for a period of 60 days; or

          (iv)   Any representation or warranty of Aether contained in this
     Agreement shall prove to be false or misleading in any material respect.

     (b)  The following events shall constitute an event of default by RESPONSE
     under this Agreement (an "RESPONSE" Event of Default"):

          (i)    RESPONSE shall fail to observe or perform any of its covenants
     or agreements contained in this Agreement and such failure remains uncured
     for a period of 10 days after receipt by RESPONSE of written notice from
     Aether of such failure;

          (ii)   RESPONSE shall (A) make an assignment for the benefit of
     creditors, (B) file a petition in bankruptcy, (C) be adjudicated insolvent
     or bankrupt, (D) petition or apply to


                                       5

<PAGE>   6
     any tribunal for any receiver or for any trustee for it under any
     reorganization, arrangement, readjustment of debt, dissolution or
     liquidation law or statute or (E)  have commenced against it any such
     proceeding or if an order for relief shall be entered that remains
     undismissed for a period of 60 days, or RESPONSE by any act indicates its
     consent to, approval of, or acquiescence in, any such proceeding, order
     for relief or the appointment of any receiver of or any trustee for it or
     suffers any such receivership or trusteeship to continue undischarged for
     a period of 60 days; or

          (iii)  RESPONSE fails to pay any amount properly due to Aether when
     due if such failure shall continue unremedied for a period of 10 days after
     receipt by RESPONSE of notice thereof from Aether.

     (c)  On the occurrence of any event of default by either party hereunder,
the other party shall be entitled to terminate this Agreement.  In addition,
termination of this Agreement by the party not in default in accordance with
the terms hereof shall be without prejudice to any other rights or remedies
such party shall have by law.

     (d)  Except as otherwise expressly provided, termination of this Agreement
will not relieve either party from fulfilling its obligations that by their
terms or nature survive termination.


ARTICLE X - DISPUTE RESOLUTION

     Any controversy or claim arising out of or relating to this Agreement, or
the breach thereof, shall be settled by final and binding arbitration
administered by the American Arbitration Association under its Commercial
Arbitration Rules.  Such arbitration shall take place in Washington, D.C.
before a panel of three neutral arbitrators selected pursuant to such Rules.
The arbitrators' award shall include an allocation of arbitration fees,
expenses, and compensation, and may include an award to the prevailing party of
its attorney's fees, costs, and expenses in connection with the arbitration.  A
judgment on the award rendered by the arbitrators may be entered in and
enforced by any court having jurisdiction thereof, each party hereby consenting
to the jurisdiction of such court over it and waiving, to the fullest extent
permitted by law, any defense or objection relating to in personam
jurisdiction, subject matter jurisdiction, venue, or convenience of the forum.
All matters arising in any action to enforce an arbitral award shall be
determined in accordance with the law and practice of the forum court.


ARTICLE XI - ACCEPTANCE TESTING

     RESPONSE will develop a detailed Acceptance Test Plan (ATP) to validate
system functional load/stress requirements of the system. A draft ATP will be
provided to Aether at least 10 days prior to actual performance of the
Acceptance Test. Aether may comment on the draft.


                                       6

<PAGE>   7
RESPONSE will develop the ATP from the requirements and specifications for the
RESPONSE software and will, to the maximum extent feasible, incorporate
Aether's comments in the final ATP.


ARTICLE XII - EXCLUSIVITY

     Aether agrees not to engage in development of Emergency Services Call
Center software for a competitor or potential competitor to RESPONSE's for a
period of three years after execution of this agreement, unless with the
express prior written consent of RESPONSE.  Nor will Aether enter into the
business of providing operator assisted emergency, roadside or vehicle
concierge functions for a period of three years after execution of this
Agreement, without the express prior written consent of RESPONSE.  Aether
further agrees to refrain from hiring RESPONSE personnel for a period of three
years after execution of this Agreement.


ARTICLE XIII - PROJECT PHASES

     RESPONSE reserves the right to approve all tasks set forth in the SOW, on
a phased basis.  The phases will be:

Phase I:  System Design & Engineering, RC Architecture and Software Design
Specs (approximately $200,000).
Phase II:  Software Development (excepting ERS spotting) (approximately
$500,000)
Phase III:  ERS spotting, software integration, test and documentation
(approximately $200,000)
Phase IV:  Call center testing and validation (approximately $100,000)

Upon completion of each Phase within the scheduled time and to the satisfaction
of RESPONSE; RESPONSE will then expressly authorize Aether to commence work on
the subsequent phase.


ARTICLE XIV - MISCELLANEOUS

     (a)  Notices.  All notices and other communications hereunder shall be in
writing and shall be deemed given upon receipt if delivered personally or by
facsimile (answer back received), one (1) business day after being sent by
express or courier mail, or three (3) business days after being sent by
registered or certified mail, return receipt requested, postage prepaid, to the
parties at the following addresses (or such other address for a party as shall
be specified by like notice, provided that such notice shall be effective only
upon receipt thereof):


                                       7


<PAGE>   8
RESPONSE SERVICES CENTER, LLC:


     RESPONSE,
     Suite 130
     1099 Winterson Road
     Linthicum, MD  21090
     Telephone:   (410) 684-3434
     Facsimile:   (410) 684-6262
     Attention:   Robert W. Kelly, Vice President, Business Operations &
                  General Counsel

AETHER:

     Aether Systems Incorporated,
     11460 Cronridge Drive
     Owings Mills, MD  21117
     Telephone:   (410)654-6400
     Facsimile:   (410)654-6554
     Attention:   Cal Cassidy, Program Manager

     (b)    Technical Representatives.  Each party has designated the following
individual within its organization as an authorized representative to act on its
behalf regarding all technical matters hereunder:

     RESPONSE:  William A. Tolhurst, Vice President, Advanced Programs Aether:
     Andy Meister, Vice President Technical Sales

     (c)    Binding Effect; Assignment.  This Agreement shall be binding upon
the parties and their successors and assigns.  Neither this Agreement nor any
interests or obligations hereunder shall be assigned or transferred (by
operation of law or otherwise) to any person, company, or entity without the
prior written consent of the other party; provided that RESPONSE may assign this
Agreement without the prior consent of Aether to any person, company, or entity
acquiring all or substantially all of the assets of RESPONSE whether by
purchase, merger, acquisition of shares, or any other means.

     (d)    Entire Agreement; Amendments.  This Agreement and all exhibits
contain the entire understandings between Aether and RESPONSE and supersede all
prior written and oral understandings relating to the subject hereof.  No
representations, agreements or understandings not contained herein shall be
valid or effective unless agreed to in writing and signed by both parties.  Any
modification or amendment of this Agreement must be in writing and signed by
both parties.

     (e)    Proprietary Information.   The parties acknowledge execution of the
Mutual Non-Disclosure Agreement dated November 14, 1999 and agree to abide by
its terms.

                                       8
<PAGE>   9
     (f)     Governing Law.  The construction, interpretation and performance of
this Agreement, as well as the legal relations of the parties arising hereunder,
shall be governed by and construed in accordance with the laws of the State of
Maryland, without giving effect to the conflict or choice of law provisions
thereof.

     (g)     Waiver.   It is understood and agreed that no failure or delay by
either RESPONSE or Aether in exercising any right, power or privilege hereunder
shall operate as a waiver thereof, nor shall any single or partial exercise
thereof preclude any other or further exercise thereof, or the exercise of any
other right, power or privilege hereunder.  No waiver of any terms or conditions
of this Agreement shall be deemed to be a waiver of any subsequent breach of any
term or condition. All waivers must be in writing and signed by both parties.

     (h)     Severability.   If any part of this Agreement shall be held invalid
or unenforceable, such determination shall not affect the validity or
enforceability of any remaining portion, which shall remain in force and effect
as if this Agreement had been executed with the invalid or unenforceable portion
thereof eliminated.

     (i)     Headings.   Headings in this Agreement are included for convenience
of reference only and shall not constitute a part of this Agreement for any
other purpose.

     (j)     Independent Contractors.   RESPONSE and Aether are independent
contractors to one another, neither party has the authority to bind the other in
anyway or to any third party, and nothing in this Agreement shall be construed
as granting either party the right or authority to act as a representative,
agent, employee or joint venturer of the other.

     (k)     Survival of Terms.   The parties to this Agreement recognize and
agree that their rights and obligations under Sections 2(b), 2(c), 5, 7, 9, 12,
14, and 15 of this Agreement shall survive the termination or expiration of this
Agreement.

     (l)     Aether agrees to provide continuing technical support for their
deliverables at terms to be negotiated in good faith.  If Aether is unwilling or
unable to provide such support, then Aether shall, on a time and materials basis
and at a total cost not to exceed 5% of the total contract value, provide
training to RESPONSE and/or its contractors/assigns sufficient to allow RESPONSE
to conduct ongoing technical support of a level equal to that which could have
been provided by Aether.

     (m)     Prior to commencement of work specified in this Agreement, Aether
shall provide RESPONSE with personnel resources required thereunder, and
identify all personnel which are not currently employed by Aether as well as
estimated time those personnel resources will be required in order to avoid
possible schedule delays.

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the date first above written.

                                       9

<PAGE>   10
RESPONSE                                 AETHER SYSTEMS INCORPORATED

By: /s/ DANIEL L. DICKERSON              By: /s/ DAVID C. REYMANN
   -------------------------------          -------------------------------
   Name    Daniel L. Dickerson                 Name:   David C. Reymann
   Title:  President and CEO                   Title:  Chief Financial Officer
   Telephone: (410) 684-3400                   Telephone: (410) 654-6400
Facsimile:    (410) 684-6262                Facsimile:    (410) 654-6554

                                       10

<PAGE>   1
AETHER SYSTEMS, INC.
COMPUTATION OF EARNINGS PER COMMON SHARE
EXHIBIT 11.1

<TABLE>
<CAPTION>
                                                   Pro Forma Computation of Earnings
                                                            per Common Share
                                                 -------------------------------------
                                                 (in thousands, except per share data)

                                                     Year Ended December 31, 1997
                                                 -------------------------------------
                                                 Net Loss       Shares       Per Share
                                                 --------       ------       ---------
<S>                                              <C>            <C>          <C>
BASIC EPS
Pro forma net loss available to
              common shareholders                (2,747)        12,656         (0.22)

EFFECT OF DILUTIVE SHARES
Stock options                                         -              -             -
                                                 ------         ------         -----

DILUTIVE EPS (1)
Pro forma net loss available to
              common shareholders                (2,747)        12,656         (0.22)
                                                 ------         ------         -----
</TABLE>

<TABLE>
<CAPTION>
                                                      Year Ended December 31, 1998
                                                 -------------------------------------
                                                 Net Loss       Shares       Per Share
                                                 --------       ------       ---------
<S>                                              <C>            <C>          <C>

BASIC EPS
Pro forma net loss available to
              common shareholders
                                                 (4,693)        15,916         (0.29)

EFFECT OF DILUTIVE SHARES
Stock options
                                                       -             -             -
                                                 ------         ------         -----

DILUTIVE EPS (1)
Pro forma net loss available to
              common shareholders
                                                 (4,693)        15,916         (0.29)
                                                 ------         ------         -----
</TABLE>

<TABLE>
<CAPTION>
                                                     Year Ended December 31, 1999
                                                 -------------------------------------
                                                 Net Loss       Shares       Per Share
                                                 --------       ------       ---------
<S>                                              <C>            <C>          <C>

BASIC EPS
Pro forma net loss available to
              common shareholders
                                                (30,691)         21,207        (1.45)

EFFECT OF DILUTIVE SHARES
Stock options
                                                      -               -             -
                                                 ------         ------         -----

DILUTIVE EPS (1)
Pro forma net loss available to
              common shareholders
                                                (30,691)         21,207        (1.45)
                                                 ------         ------         -----

</TABLE>
<PAGE>   2
<TABLE>
<CAPTION>
                                         Year Ended December 31, 1999 (Pro Forma Acquisitions)
                                         ----------------------------------------------------
                                         Net Loss               Shares             Per Share
                                         --------               ------             ---------
<S>                                     <C>                    <C>                <C>
BASIC EPS
Pro forma net loss available
        to common shareholders          (435,021)                25,745                (16.90)

EFFECT OF DILUTIVE SHARES                      -                      -                     -
stock options
                                        --------                -------               -------

DILUTIVE EPS(1)
Pro forma net loss available to
          common shareholders           (435,021)                25,745                (16.90)
                                        --------                -------               -------
</TABLE>

<TABLE>
<CAPTION>
                                                      Year Ended December 31, 1999
                                         (Pro Forma Acquisitions and Common Stock Offering)
                                         --------------------------------------------------
                                         Net Loss               Shares            Per Share
                                         --------               ------            ---------
<S>                                     <C>                    <C>               <C>
BASIC EPS
Pro forma net loss available to
          common shareholders           (435,021)                28,236                (15.41)

EFFECT OF DILUTIVE SHARES
Stock options                                  -                      -                     -
                                         -------                 ------             ---------

DILUTIVE EPS(1)
Pro forma net loss available to
          common shareholders           (435,021)                28,236                (15.41)
                                        --------                 ------             ---------
</TABLE>

<TABLE>
<CAPTION>
                                                               Year Ended December 31, 1999
                                         (Pro Forma Acquisitions, Common Stock and Convertible Notes Offering)
                                         --------------------------------------------------------------------
                                         Net Loss                         Shares                    Per Share
                                         --------                         ------                    ---------
<S>                                     <C>                             <C>                       <C>

BASIC EPS
Pro forma net loss available to
          common shareholders            (449,461)                        28,236                      (15.92)

EFFECT OF DILUTIVE SHARES
Stock options                                   -                              -                           -
                                         --------                        -------                     -------

DILUTIVE EPS(1)
Pro forma net loss available to
          common shareholders           (449,461)                        28,236                       (15.92)
                                         --------                        -------                     -------
</TABLE>

<TABLE>
<CAPTION>
                                                    Year Ended December 31, 1999
                                       (Pro Forma Acquisitions and Convertible Notes Offering)
                                       -------------------------------------------------------
                                         Net Loss               Shares            Per Share
                                         --------               ------            ---------
<S>                                     <C>                    <C>               <C>
BASIC EPS
Pro forma net loss available to
          common shareholders           (449,461)                25,745                (17.45)

EFFECT OF DILUTIVE SHARES
Stock options                                  -                      -                     -
                                         -------                 ------             ---------

DILUTIVE EPS(1)
Pro forma net loss available to
          common shareholders           (449,461)                25,745                (17.45)
                                        --------                 ------             ---------
</TABLE>

1. Options and warrants to purchase approximately 1.000 million, 1.559 million,
4.077 million shares of common stock were outstanding during 1997, 1998, and
1999 and pro formas for 1999, respectively. In the computation of pro forma
diluted earnings per share because the effect would have been antidilutive.


<PAGE>   1

                                                                    EXHIBIT 11.2

                              AETHER SYSTEMS, INC.

                 SCHEDULE OF RATIO OF EARNINGS TO FIXED CHARGES

<TABLE>
<CAPTION>
                                                YEAR ENDED DECEMBER 31,
                        ------------------------------------------------------------------------
                                              HISTORICAL
                        -------------------------------------------------------     PRO FORMA(1)
                          1996          1997           1998            1999            1999
                        ---------    -----------    -----------    ------------    -------------
<S>                     <C>          <C>            <C>            <C>             <C>
Pre-tax loss from
  continuing
  operations..........  $(416,980)   $(2,747,177)   $(4,693,272)   $(30,691,494)   $(449,460,491)
Fixed Charges:
  Interest expense....         --             --         70,171       1,056,718       15,496,718
  Rent expense
     interest
     factor...........     16,333         28,000         30,333          94,000          202,000
                        ---------    -----------    -----------    ------------    -------------
                           16,333         28,000        100,504       1,150,718       15,698,718
                        ---------    -----------    -----------    ------------    -------------
Earnings as
  adjusted............   (400,647)    (2,719,177)    (4,592,768)    (29,540,776)    (443,761,773)
Fixed charges from
  above...............     16,333         28,000        100,504       1,150,718       15,698,718
Fixed charges exceed
  earnings by.........  $ 416,980    $ 2,747,177    $ 4,693,272    $ 30,691,494    $ 449,460,491
                        =========    ===========    ===========    ============    =============
</TABLE>
- --------------
(1)  Gives effect to the Mobeo and LocusOne acquisitions and the pending
     acquisition of Riverbed, the offering of convertible notes and the
     concurrent common stock offering.

<PAGE>   1
                                                                    EXHIBIT 21.1

                                  Subsidiaries


                        LocusOne Communications, Inc.
                        Aether OpenSky Investments LLC
                        Mobeo, Inc.
                        RT Acquisition, Inc.





<PAGE>   1
CONSENT OF KPMG LLP


                                                             Exhibit 23.1

                         INDEPENDENT AUDITORS' CONSENT

The Board of Directors
Aether Systems, Inc.

The audits referred to in our report dated February 9, 2000, included the
related financial statement schedule for each of the years in the three-year
period ended December 31, 1999, included in the registration statement. This
financial statement schedule is the responsibility of the Company's management.
Our responsibility is to express an opinion on this financial statement schedule
based on our audits. In our opinion, such financial statement schedule, when
considered in relation to the basic consolidated financial statements taken as a
whole, presents fairly in all material respects the information set forth
therein.

We consent to the use of our reports included herein and to the references to
our Firm under the headings "Selected Consolidated Financial Data" and
"Experts" in the prospectus.

                                        /s/ KPMG LLP


McLean, Virginia
February 22, 2000

<PAGE>   1
                                                                    Exhibit 23.2

                       CONSENT OF INDEPENDENT ACCOUNTANTS

We hereby consent to the use in this Registration Statement on Form S-1 of our
report dated March 10, 1999 relating to the financial of Mobeo, Inc., which
appear in such Registration Statement. We also consent to the references to us
under the heading "Experts" in such Registration Statement.

/s/ PricewaterhouseCoopers LLP

McLean, Virginia
February 22, 2000


<PAGE>   1
                                                                    Exhibit 23.4

                       Consent to Be Named as a Director

         I hereby consent to be named as a person who will become a director of
Aether Systems, Inc. (the "Company") in the registration statement on Form S-1
to be filed by the Company with the Securities and Exchange Commission relating
to the public offering by the Company of shares of common stock, par value
$.01, and subordinated convertible debentures, of the Company.


                                                 /s/ E. WAYNE JACKSON, III
                                             ----------------------------------
                                                     E. Wayne Jackson, III


<PAGE>   1
                                                                    EXHIBIT 23.5

                       Consent to Be Named as a Director


     I hereby consent to be named as a person who will become a director of
Aether Systems, Inc. (the "Company") in the registration statement on Form S-1
to be filed by the Company with the Securities and Exchange Commission relating
to the public offering by the Company of shares of common stock, par value $.01,
and subordinated convertible debentures, of the Company.


                                        /s/ ROBIN VASAN
                                        -------------------------
                                        Robin Vasan

<PAGE>   1

                                                                    Exhibit 23.6


[FORRESTER LOGO]



February 16, 2000


Carl Gardiner
Merrill Lynch
World Financial Center, North Tower
250 Vesey Street
New York, NY 10281

To Whom It May Concern:

Pursuant to the contract between Merrill Lynch and Forrester Research, Inc.
("Forrester") Forrester consents to the inclusion of our name and to the
references to the language set forth below in a prospectus to be filed on behalf
of Merrill Lynch's client (together with the preliminary prospectus and the
final prospectus to be circulated among prospective investors).

Forrester hereby consent to the following:

"Forrester Research forecasts that business-to-business Internet commerce in the
U.S. will increase from an estimated $406.2 billion in 2000 to $2.7 trillion in
2004."

"Forrester Research forecasts that 7.1 million European business professionals
and trendy young adults will own WAP smartphones by the end of 2000 and that
there will be 40 million Europeans generally using WAP phones by the end of
2001."

Forrester does not consent to be an expert under the Securities Act of 1933 or
as having prepared or certified any part of the Registration Statement.
Further, Forrester specifically does not consent to Merrill Lynch or its client
filing this letter in connection with the filing of the prospectus.

Please feel free to call me at 617/613-6011 if your have any questions.

Very truly yours,

/s/Michael R. Shirer
- ----------------------
Michael R. Shirer
Public Relations Manager

<PAGE>   1
                                                                    Exhibit 23.7

[IDC LOGO]                                        IDC
                                                  5 Speen Street
                                                  Framingham, MA 01701
                                                  (508) 872-8200
                                             Fax: (508) 935-4789
                                         Web Site: http://www.idc.com

                                DISCLOSURE FORM

IDC grants Aether Systems, Inc., permission to disclose select data of IDC's
publication, entitled: The Global Market Forecast for Internet Usage and
Commerce: Based on the Internet Commerce Market Model, Version 5 (#19262, June
1999); The Intranet Opportunity; (#18774, April 1999), Worldwide Cellular/PCS
Forecast (#20113, Sept. 1999); and US Remote and Mobile Worker Market Review and
Forecast (#19262, July 1999.

It is understood by both IDC and Aether Systems, Inc., that the information
will not be sold. It is further understood that IDC will be credited as the
source of publication.


/s/ Alexa McCloughan                                   2-22-00
- -------------------------------------              ---------------
Alexa McCloughan, Vice President                   Date
International Data Corporation
Aether Systems, Inc.


By: /s/ David C. Reymann                               2-22-00
- -------------------------------------              ---------------
Requesting individual, company                     Date
CFO

<PAGE>   1
                              CONSENT OF KPMG LLP

                                                                    Exhibit 23.8

                         INDEPENDENT AUDITORS' CONSENT

The Board of Directors
Riverbed Technologies, Inc.

We consent to the use of our report included herein and to the reference to our
Firm under the heading "Experts" in the prospectus.

                                        /s/ KPMG LLP

McLean, Virginia
February 22, 2000


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