<PAGE>   1
                                                                   EXHIBIT 10.11



                           SOFTWARE LICENSE AGREEMENT

                       AETHER INTELLIGENT MESSAGING (AIM)

       This Software License Agreement ("Agreement") is made effective as of the
date last executed below ("Effective Date") by and between Aether Technologies
International, L.L.C. (hereinafter, "Aether" or "Aether Technologies"), located
at 11460 Cronridge Drive, Owings Mills, MD 21117, and AirWeb Corporation (d/b/a
OpenSky Corporation) ("Licensee"), located at 471 Emerson Street, Suite 200,
Palo Alto, CA 94301.

       The parties agree as follows:

       1. Licensed Software. The software to be licensed to Licensee (which
excludes all of Licensee's affiliates, subsidiaries, partnerships, associations
or other entities or legal relationships in whatever form (collectively referred
to as "Licensee's Subsidiaries")), is Aether's AIM software and documentation
(the "Licensed Software"), as described on Exhibit A. The portion of the
Licensed Software described on Exhibit B hereto is referred to herein as the
"Client Code." All references herein to Licensed Software shall include the
Client Code.

       2. License Grant. Subject to the terms of this Agreement, Aether grants
to Licensee a personal, perpetual, worldwide, irrevocable, royalty-free,
non-exclusive and, except as provided in Section 7, non-transferable license to
(a) reproduce, display and use the Licensed Software at any of Licensee's data
centers and (b) reproduce, sublicense and distribute, directly or indirectly
through value added resellers, original equipment manufacturers, system
integrators or other intermediaries, the Client Code solely for use by
Licensee's customers on wireless hardware devices. Before copying the Licensed
Software, Licensee shall provide Aether with 90 days' written notice and Aether
will have the opportunity to make copies of the Licensed Software and install
such copies in additional data centers identified by Licensee. Licensee shall
also have the right to make two copies of the Licensed Software as archival or
backup copies for its own internal use. No rights are granted under this
Agreement to modify the Licensed Software. Except as otherwise provided in this
Section 2, Licensee is expressly prohibited from licensing or distributing the
Licensed Software to any third party, which includes Licensee's Subsidiaries,
without the prior written permission of Aether, and any such attempted license
or distribution is a material breach of this Agreement.

       Licensee acknowledges that the Licensed Software contains intellectual
property belonging exclusively to Aether Technologies. Except as provided
herein, Licensee acknowledges and agrees that this Agreement does not grant any
right, title or interest in and to any patents, copyrights, trade secrets,
trademarks or other property rights or rights of ownership in the Licensed
Software in whatever form. All rights not expressly granted by Aether hereunder
are reserved by Aether Technologies.

       3. License Fee. No fees are due and payable by Licensee to Aether or from
Aether to Licensee for the license granted or services provided pursuant to this
Agreement. Aether has agreed to enter into this Agreement as consideration for
the shares of Series A Preferred Stock of Licensee issued and sold to Aether by
Licensee as set forth in that certain Series A Preferred Stock Purchase
Agreement, dated as of August 9, 1999.

       4. Copyright Notice. OpenSky shall reproduce all copyright notices
contained in the Licensed Software on each copy made by Licensee of the Licensed
Software in whatever form.

<PAGE>   2

       5. Term. This Agreement shall be effective as of the Effective Date and
shall remain in effect until terminated pursuant to this Section 5. Either party
may terminate this Agreement by providing written notice to the other party if
the other party is in material breach of this Agreement and has not remedied
such breach within thirty (30) days of notice thereof. The parties agree that
their respective obligations and applicable limitations under Sections 2
(License Grant), 7 (No Assignment; No Reverse Engineering), 8 (Confidentiality),
9 (Representations and Warranties), 10 (Indemnification), and 11 (Limitation of
Liability) shall survive any expiration or termination of this Agreement and
that any other obligations and duties which by their nature extend beyond the
expiration or termination of this Agreement shall survive any expiration or
termination and shall remain in effect for a period of ten (10) years
thereafter.

       6. Support.

              (a) Aether shall, at Aether's sole expense, provide Licensee with
       all Updates as they become commercially available to Aether's licensees.
       In this Agreement, "Updates" means all new versions of the Licensed
       Software, including all error corrections, patches, work-arounds, fixes,
       enhancements, new versions defined by changes to the version number
       (e.g., 2.0 to 3.0).

              (b) Should Licensee need any custom modifications to the Licensed
       Software, Aether agrees to negotiate in good faith an agreement for the
       provision of such modifications on a time and materials basis.

              (c) If at any time during the term of this Agreement, the Licensed
       Software fails to substantially conform to the Documentation, Aether
       shall, at its option, either modify or replace the Licensed Software to
       conform to the Documentation in a prompt manner after receiving notice of
       any substantial nonconformity from Licensee.

       7. No Assignment; No Reverse Engineering. Neither this Agreement nor the
rights or obligations hereunder, either in whole or in part, may be assigned or
otherwise transferred, whether voluntarily or by operation of law, by Licensee
without the prior written consent of Aether, which consent may be withheld in
Aether's sole discretion, and any attempted transfer or assignment is null and
void and shall be deemed a material breach of this Agreement. Notwithstanding
the foregoing, Licensee may assign this Agreement to an acquirer of all of the
stock or substantially all of the assets of Licensee. Licensee shall not reverse
engineer, reverse compile or disassemble the Licensed Software.

       8. Confidentiality. Licensee hereby acknowledges that the Licensed
Software, embodied in whatever form or media, constitutes a valuable trade
secret belonging to Aether, and Licensee agrees to hold such trade secret in
strict confidence, and not to use or disclose such trade secret, except as
permitted hereunder. Licensee further acknowledges that Aether is the owner of
and retains all title to the Licensed Software recorded on the original media
and all subsequent copies regardless of the form or media.

       9. Representations and Warranties.

              (a) Each party represents and warrants to the other that (i) it
       has the legal right and corporate power and authority to execute,
       deliver, and perform this Agreement, provided that the sole and exclusive
       remedy for a breach of this Subsection 9 as it relates to intellectual
       property rights will be the indemnification obligations (including the
       limits thereto) set forth in Section 10; (ii) its execution, delivery,
       and performance of this Agreement has been duly authorized in accordance
       with all appropriate corporate power and authority; (iii) the individual
       signing this Agreement on its behalf has

<PAGE>   3

       been authorized to execute this Agreement in the capacity set forth under
       such individual's name on the signature page hereof; and (iv) the
       execution, delivery, and performance of this Agreement constitutes its
       legal, valid, and binding obligation enforceable against it in accordance
       with its terms, except as enforcement may be limited by applicable
       bankruptcy, insolvency, reorganization, or other similar laws affecting
       the enforcement of creditors' rights generally and that the remedy of
       specific performance may be subject to judicial discretion.

              (b) Aether represents and warrants to Licensee that the Licensed
       Software will perform substantially in accordance with its Documentation.

       10. Indemnification.

              (a) General. Aether, at its own expense, will indemnify and defend
       Licensee, its employees, representatives, agents and affiliates against
       any claim, suit, action or proceeding based on or arising from a claim
       brought by a third party that the use, copying, display, or distribution
       of the Licensed Software by Licensee as permitted in Section 2 infringes
       in any manner Intellectual Property Right of any third party. In this
       Agreement, "Intellectual Property Rights" means all rights in, to, or
       arising out of: (i) any U.S., international or foreign patent or any
       application therefor and any and all reissues, divisions, continuations,
       renewals, extensions and continuations-in-part thereof; ii) inventions
       (whether patentable or not in any country), invention disclosures,
       improvements, trade secrets, proprietary information, know-how,
       technology and technical data; (iii) copyrights, copyright registrations,
       mask works, mask work registrations, and applications therefor in the
       U.S. or any foreign country, and all other rights corresponding thereto
       throughout the world; (iv) moral rights; and (v) any other proprietary
       rights anywhere in the world similar to those described in this
       definition. Aether's obligations set forth in this Section 10 are
       conditioned on (i) Aether's prompt notice of any indemnified claim, and
       (ii) Licensee permits Aether to assume and control the defense of the
       action, with counsel chosen by Aether. Aether will pay any and all costs,
       damages, and attorneys fees awarded against Licensee in connection with
       or arising from any such claim, suit or proceeding.

              (b) Election of Remedy. In the event that Licensee's ability to
       use the Licensed Software is enjoined due to a claim covered by the
       indemnity obligations set forth in Section 10(a) above, Aether will, at
       its option and expense, either: (i) procure for Licensee the right to use
       the Licensed Software; (ii) replace the infringing material so that it is
       non-infringing; (iii) modify the infringing material so that it is
       non-infringing or, (iv) if none of the above options are reasonably
       available after commercially reasonable attempts by Aether, Aether may,
       at its option, terminate this Agreement.

              (c) Sole and Exclusive Remedy. The foregoing states Aether's
       entire liability and Licensee's sole and exclusive remedy with respect to
       the infringement of intellectual property rights of any third party.

               (d) LIMIT ON INDEMNITY LIABILITY. IN NO EVENT SHALL AETHER'S
       AGGREGATE, CUMULATIVE LIABILITY TO LICENSEE ARISING OUT OF OR RELATING TO
       THE INDEMNITY OBLIGATIONS DESCRIBED IN THIS SECTION 10 EXCEED ONE MILLION
       DOLLARS ($1,000,000). THIS LIMITATION ON LIABILITY IS CUMULATIVE WITH ALL
       PAYMENTS BEING AGGREGATED TO DETERMINE SATISFACTION OF THE LIMIT. THE
       EXISTENCE OF ONE OR MORE CLAIMS OR SUITS UNDER THIS SECTION WILL NOT
       ENLARGE THE LIMIT.

<PAGE>   4

               (e) Warranty Disclaimer. SUBJECT TO AETHER'S OBLIGATIONS UNDER
       SECTION 9(b), AETHER TECHNOLOGIES MAKES NO REPRESENTATIONS OR WARRANTIES
       THAT THE LICENSED SOFTWARE IS FREE OF ERRORS. THE LICENSED SOFTWARE IS
       PROVIDED ON AN "AS IS" BASIS AND ALL RISK IS WITH LICENSEE. SUBJECT TO
       AETHER'S OBLIGATIONS UNDER SECTION 9(b), AETHER TECHNOLOGIES MAKES NO
       WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO ANY MATTER WHATSOEVER.
       IN PARTICULAR, ANY AND ALL WARRANTIES OF MERCHANTABILITY, OR FITNESS FOR
       A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

       11. Limitation of Liability. NEITHER PARTY SHALL BE LIABLE TO THE OTHER
PARTY OR ANY THIRD PARTY FOR ANY INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES,
LOSS OF PROFITS OR REVENUE, OR INTERRUPTION OF BUSINESS IN ANY WAY ARISING OUT
OF OR RELATED TO THIS AGREEMENT, REGARDLESS OF THE FORM OF ACTION, WHETHER IN
CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT PRODUCT LIABILITY OR OTHERWISE,
EVEN IF ANY REPRESENTATIVE OF THE PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

       12. Entire Agreement. This Agreement and any attachments hereto represent
the entire agreement and understanding of the parties with respect to the
subject matter hereof and supersede all prior representations, understandings
and agreements, whether oral or written, with respect to such subject matter.
This Agreement may be modified only by a writing executed by both parties
hereto.

       13. Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Maryland as such laws are applied to
agreements entered into and to be performed entirely within Maryland between
Maryland residents and by the laws of the United States. The parties hereby
submit to the jurisdiction of the State of Maryland, and the United States
District Court of Maryland, and agree that such tribunals shall have
jurisdiction and venue over all controversies in connection herewith. The
parties exclude in its entirety the application to this Agreement of the United
Nations Convention on Contracts for the International Sale of Goods.

       14. Export Regulations. Licensee shall not export, directly or
indirectly, any information acquired under this Agreement or any products
utilizing any such information to any country for which the U.S. Government or
any agency thereof at the time of export requires an export license or other
government approval without first obtaining such license or approval.

       15. Relationship of the Parties. Each of the parties shall at all times
during the term of this Agreement act as, and shall represent itself to be, an
independent contractor, and not an agent or employee of the other.

        16. Waiver. A waiver of any default hereunder or of any of the terms and
conditions of this Agreement shall not be deemed to be a continuing waiver or a
waiver of any other default or of any other term or condition, but shall apply
solely to the instance to which such waiver is directed. The exercise of any
right or remedy provided in this Agreement shall be without prejudice to the
right to exercise any other right or remedy provided by law or equity, except as
expressly limited by this Agreement.

       17. Injunctive Relief. The copying or use of the Licensed Software in a
manner inconsistent with any provision of this Agreement will cause irreparable
injury to Aether for which Aether will not have an adequate remedy at law.
Aether shall be entitled to equitable relief in court, including but not limited
to temporary restraining orders, preliminary injunctions and permanent
injunctions.

       18. Severability. In the event any provision of this Agreement is found
to be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or

<PAGE>   5

impaired.

       19. Notices. Any notice provided for or permitted under this Agreement
will be treated as having been given when (a) delivered personally, (b) sent by
confirmed telex or telecopy, (c) sent by commercial overnight courier with
written verification of receipt, or (d) mailed postage prepaid by certified or
registered mail, return receipt requested, to the signatory of the party to be
notified, at the address set forth above, or at such other place of which the
other party has been notified in accordance with the provisions of this Section
19 (Notices). Copies of all notices to Aether shall also be sent to the
following address: Aether Technologies, Attention, Chief Financial Officer,
11460 Cronridge Drive, Owings Mills, MD 21117, telecopy (410) 654-6554. Copies
of all notices to Licensee shall also be sent to the following address: Wilson,
Sonsini, Goodrich & Rosati, Attention: Aaron J. Alter, Esq., 650 Page Mill Road,
Palo Alto, CA 94304, facsimile (650) 493-6811. Notices will be treated as having
been received upon the earlier of actual receipt or five (5) days after posting.

<PAGE>   6

        IN WITNESS WHEREOF, the parties have caused this Agreement to be
executed by their duly authorized representatives effective as of the Effective
Date.

Licensee:                                    Aether Technologies International,
AirWeb Corporation                           L.L.C.:
(d/b/a OpenSky Corporation)


By:  /s/ Michael D. Dolbec                   By: /s/ David S. Oros
   --------------------------------              -------------------------------
Printed: Michael D. Dolbec                   Printed: David S. Oros
        ---------------------------                  ---------------------------
Title:  CFO and Secretary                    Title: Manager
      -----------------------------                -----------------------------
Date:   August 9, 1999                       Date: 8/9/99
     ------------------------------               ------------------------------

<PAGE>   7

                                   SCHEDULE A

                             DETAILED SOFTWARE LIST
    The object code for the software described in the attached documentation
                         and the attached documentation

<PAGE>   8

                                   SCHEDULE B

                           DESCRIPTION OF CLIENT CODE
The object code for the Client Software described in the attached documentation
         and the attached documentation relating to the Client Software