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                                                                   Exhibit 10.28

                                                               EXECUTION VERSION

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                            TRUST AGREEMENT [N296SK]

                          Dated as of December 20, 2001

                                     between

                       SILVERMINE RIVER FINANCE TWO, INC.,
                              as Owner Participant

                                       and

                WELLS FARGO BANK NORTHWEST, NATIONAL ASSOCIATION,
                                as Owner Trustee

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

                  Covering One Embraer Model EMB-145LR Aircraft
                      Bearing U.S. Registration No. N296SK
                     and Manufacturer's Serial Number 145514

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                                                TABLE OF CONTENTS
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                                                                                                       PAGE
                                                                                                      
ARTICLE I      DEFINITIONS AND TERMS......................................................................1
     Section 1.1.   Definitions...........................................................................1

ARTICLE II     AUTHORITY TO EXECUTE CERTAIN OPERATIVE AGREEMENTS; DECLARATION OF TRUST....................1
     Section 2.1.   Authority to Execute Documents........................................................1
     Section 2.2.   Declaration...........................................................................1

ARTICLE III    ACCEPTANCE AND DELIVERY OF AIRCRAFT; LEASE OF AIRCRAFT; REPLACEMENT........................2
     Section 3.1.   Authorization.........................................................................2
     Section 3.2.   Conditions Precedent..................................................................3
     Section 3.3.   Postponement of Delivery Date.........................................................3
     Section 3.4.   Authorization in Respect of a Replacement Airframe or Replacement Engines.............3
     Section 3.5.   Trust Agreement Remaining in Full Force and Effect....................................4
     Section 3.6.   Authorization in Respect of Return of an Engine.......................................4

ARTICLE IV     RECEIPT, DISTRIBUTION AND APPLICATION OF INCOME FROM THE TRUST ESTATE......................4
     Section 4.1.   Distribution of Payments..............................................................4
     Section 4.2.   Method of Payments....................................................................4

ARTICLE V      DUTIES OF THE OWNER TRUSTEE................................................................5
     Section 5.1.   Notice of Event of Default............................................................5
     Section 5.2.   Action Upon Instructions..............................................................5
     Section 5.3.   Indemnification.......................................................................6
     Section 5.4.   No Duties Except as Specified in Trust Agreement or Instructions......................6
     Section 5.5.   No Action Except Under Specified Documents or Instructions............................7

ARTICLE VI     THE OWNER TRUSTEE..........................................................................7
     Section 6.1.   Acceptance of Trusts and Duties.......................................................7
     Section 6.2.   Absence of Certain Duties.............................................................7
     Section 6.3.   No Representations or Warranties as to Certain Matters................................8
     Section 6.4.   No Segregation of Monies Required; Investment Thereof.................................9
     Section 6.5.   Reliance Upon Certificates, Counsel and Agents........................................9
     Section 6.6.   Not Acting in Individual Capacity.....................................................9
     Section 6.7.   Fees; Compensation....................................................................9
     Section 6.8.   Tax Returns..........................................................................10
     Section 6.9.   Fixed Investment Trust...............................................................10

ARTICLE VII    INDEMNIFICATION OF THE OWNER TRUSTEE BY THE OWNER PARTICIPANT.............................10
     Section 7.1.   The Owner Participant to Indemnify the Owner Trustee.................................10
</Table>

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<Caption>
                                                                                                       PAGE
                                                                                                      
ARTICLE VIII   SUCCESSOR OWNER TRUSTEES; CO-TRUSTEES.....................................................11
     Section 8.1.   Resignation of the Owner Trustee; Appointment of Successor...........................11
     Section 8.2.   Co-Trustees and Separate Trustees....................................................12

ARTICLE IX     SUPPLEMENTS AND AMENDMENTS TO TRUST AGREEMENT  AND OTHER DOCUMENTS........................14
     Section 9.1.   Supplements and Amendments...........................................................14
     Section 9.2.   Discretion as to Execution of Documents..............................................14
     Section 9.3.   Absence of Requirements as to Form...................................................14
     Section 9.4.   Distribution of Documents............................................................14

ARTICLE X      MISCELLANEOUS.............................................................................14
     Section 10.1.  Termination of Trust Agreement.......................................................14
     Section 10.2.  The Owner Participant Has No Legal Title in Trust Estate.............................15
     Section 10.3.  Assignment, Sale, etc., of Aircraft..................................................15
     Section 10.4.  Trust Agreement for Benefit of Certain Parties Only..................................15
     Section 10.5.  Notices..............................................................................15
     Section 10.6.  Severability.........................................................................16
     Section 10.7.  Waivers, etc...................................................................... ..16
     Section 10.8.  Counterparts.........................................................................16
     Section 10.9.  Binding Effect, etc................................................................ .16
     Section 10.10. Headings; References.................................................................16
     Section 10.11. GOVERNING LAW........................................................................16
     Section 10.12. Administration of Trust..............................................................17
</Table>

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                            TRUST AGREEMENT [N296SK]

          This TRUST AGREEMENT [N296SK], dated as of December 20, 2001 between
SILVERMINE RIVER FINANCE TWO, INC., a Delaware corporation (together with its
successors and permitted assigns, the "Owner Participant"), and WELLS FARGO BANK
NORTHWEST, NATIONAL ASSOCIATION, a national banking association (in its
individual capacity, "WFB") and otherwise not in its individual capacity but
solely as trustee hereunder (herein in such capacity with its permitted
successors and assigns called the "Owner Trustee") (as hereafter from time to
time supplemented or amended, this or the "Trust Agreement").

                              W I T N E S S E T H :

                                    ARTICLE I

                              DEFINITIONS AND TERMS

          Section 1.1. DEFINITIONS. Capitalized terms used herein and defined in
Appendix A shall, except as such definitions may be specifically modified in the
body of this Trust Agreement for the purposes of a particular section, paragraph
or clause, have the meanings given such terms in Appendix A and, unless
otherwise specified, such meanings shall be equally applicable to both the
singular and the plural forms of such terms.

                                   ARTICLE II

               AUTHORITY TO EXECUTE CERTAIN OPERATIVE AGREEMENTS;
                              DECLARATION OF TRUST

          Section 2.1. AUTHORITY TO EXECUTE DOCUMENTS. The Owner Participant
hereby authorizes and directs the Owner Trustee to do the following, and the
Owner Trustee agrees for the benefit of the Owner Participant that it will do
the following (i) to execute and deliver the Participation Agreement, the Lease,
the Lease Supplement covering the Aircraft, the Airframe Warranty Assignment and
Consent, the Engine Warranty Assignment and Consent and any other agreements,
instruments or documents, to which the Owner Trustee is a party in the
respective forms thereof in which delivered from time to time by the Owner
Participant to the Owner Trustee for execution and delivery and (ii) subject to
the terms hereof, to exercise its rights (upon instructions received from the
Owner Participant) and perform its duties under the documents referred to in
this Section in accordance with the terms thereof.

          Section 2.2. DECLARATION OF TRUST. The Owner Trustee hereby declares
that it will hold the Trust Estate upon the trusts hereinafter set forth for the
use and benefit of the Owner Participant, subject, however, to the provisions of
the Lease. This Trust Agreement is not intended by the Owner Participant to
create, and the trust created hereby is not intended by the Owner Participant
and the other parties interested herein to constitute a business trust for the
purposes of the Bankruptcy Code.

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                                   ARTICLE III

                      ACCEPTANCE AND DELIVERY OF AIRCRAFT;
                         LEASE OF AIRCRAFT; REPLACEMENT

          Section 3.1. AUTHORIZATION. (a) The Owner Participant hereby
authorizes and directs the Owner Trustee to, and the Owner Trustee agrees for
the benefit of the Owner Participant that, on the Delivery Date it will, subject
to due compliance with the terms of Section 3.02 hereof:

               (i) authorize a representative or representatives of the Owner
          Trustee to accept delivery of the Aircraft and the Bills of Sale
          pursuant to the Participation Agreement;

               (ii) execute and deliver each of the Operative Agreements to
          which the Owner Trustee is to be a party;

               (iii) purchase the Aircraft pursuant to the Participation
          Agreement;

               (iv) pay an amount equal to Lessor's Cost to, or at the direction
          of, Solitair and the Seller pursuant to the Participation Agreement in
          consideration of the sale of the Aircraft to the Owner Trustee
          thereunder;

               (v) make application to the FAA for registration of the Aircraft
          in the name of the Owner Trustee by filing or causing to be filed with
          the FAA (i) the FAA Bill of Sale, (ii) the FAA Aircraft Registration
          Application in the name of the Owner Trustee (including, without
          limitation, an affidavit from the Owner Trustee stating that it is a
          "citizen of the United States" within the meaning of Section
          40102(a)(15) of the Transportation Code), and (iii) this Trust
          Agreement;

               (vi) take such other action as may reasonably be required of the
          Owner Trustee hereunder or under the Participation Agreement or the
          Lease to effectuate the transactions contemplated thereby; and

               (vii) execute and deliver all such other instruments, documents
          or certificates and take all such other actions in accordance with the
          directions of the Owner Participant, as the Owner Participant may
          reasonably deem necessary or advisable in connection with the
          transactions contemplated hereby and by the other Operative
          Agreements.

          (b)  The Owner Participant hereby authorizes and directs the Owner
       Trustee to, and the Owner Trustee agrees for the benefit of the Owner
       Participant that it will:

               (i) immediately after the delivery of the Aircraft to the Owner
          Trustee, cause the Aircraft to be leased to Lessee under the Lease;
          and

               (ii) execute and deliver a Lease Supplement covering the
          Aircraft.

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          Section 3.2. CONDITIONS PRECEDENT. The right and obligation of the
Owner Trustee to take the action required by Section 3.01 hereof shall be
subject to the following conditions precedent:

          (a) the Owner Participant shall have made the full amount of the
     Commitment with respect to the Aircraft available to the Owner Trustee, in
     immediately available funds, in accordance with Section 2.01(c) of the
     Participation Agreement; and

          (b) the terms and conditions of Section 3.01 of the Participation
     Agreement shall have been waived by the Owner Participant or complied with
     in a manner satisfactory to the Owner Participant. The Owner Participant
     shall, by instructing Owner Trustee to release the full amount of the
     Commitment then held by Owner Trustee as provided in Section 2.01 of the
     Participation Agreement, be deemed to have found satisfactory to it, or
     waived, all such conditions precedent.

          Section 3.3. POSTPONEMENT OF DELIVERY DATE. The Owner Trustee, upon
instructions from the Owner Participant, shall take all action specified in
Section 2.01 of the Participation Agreement as action to be taken by the Owner
Trustee.

          Section 3.4. AUTHORIZATION IN RESPECT OF A REPLACEMENT AIRFRAME OR
REPLACEMENT ENGINES. The Owner Trustee agrees for the benefit of the Owner
Participant that, upon the receipt by a Responsible Officer of Owner Trustee of
an authorization and direction from the Owner Participant, it will, in the event
of a Replacement Airframe or Replacement Engines, if any, being substituted
pursuant to Section 8(a)(i) of the Lease, or a Replacement Engine being
substituted pursuant to Section 7(e) of the Lease, subject to due compliance
with the terms of Sections 8(d) and 7(e) of the Lease, as the case may be:

          (a) to the extent not previously accomplished by a prior
     authorization, authorize a representative or representatives of the Owner
     Trustee to accept delivery of the Replacement Airframe or Replacement
     Engines, if any, or the Replacement Engine;

          (b) accept from Lessee or other vendor of the Replacement Airframe or
     Replacement Engines, if any, or the Replacement Engine, a bill of sale or
     bills of sale (if tendered) and the invoice, if any, with respect to the
     Replacement Airframe and Replacement Engines, if any, or the Replacement
     Engine being furnished pursuant to Section 8(a)(i) or 7(e) of the Lease;

          (c) in the case of a Replacement Airframe, make application to the FAA
     (or the Aeronautical Authority of any jurisdiction other than the United
     States of America in which the Replacement Airframe is then registered in
     accordance with the terms of the Lease) for registration in the name of the
     Owner Trustee of the Aircraft of which such Replacement Airframe is a part;

          (d) execute and deliver a Lease Supplement covering (i) the Aircraft
     of which such Replacement Airframe is part of and, (ii) such Replacement
     Engine, as the case may be;

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          (e) transfer its interest in (without recourse except as to
     obligations in respect of Lessor's Liens) and to the Airframe and Engines
     (if any) or the Engine being replaced to or at the direction of Lessee; and

          (f) take such further action as may be contemplated by Sections 8(d)
     or 7(e) of the Lease, as the case may be.

          Section 3.5. TRUST AGREEMENT REMAINING IN FULL FORCE AND EFFECT. In
the event of the substitution of a Replacement Airframe for the Airframe or the
substitution of a Replacement Engine for any Engine or engine all provisions of
this Trust Agreement relating to such replaced Airframe or Engine or engine
shall be applicable to such Replacement Airframe or Replacement Engine, with the
same force and effect as if such Replacement Airframe or Replacement Engine were
the same airframe or engine as the Airframe or Engine being replaced but for the
Event of Loss with respect to such Airframe or Engine.

          Section 3.6. AUTHORIZATION IN RESPECT OF RETURN OF AN ENGINE. The
Owner Trustee agrees for the benefit of the Owner Participant that, upon the
receipt by a Responsible Officer of the Owner Trustee of an authorization and
direction from the Owner Participant, it will, in the event of an engine being
transferred to the Owner Trustee pursuant to Section 12(b) of the Lease, subject
to due compliance with the terms of such Section 12(b):

          (a) accept from Lessee or other vendor the bill of sale contemplated
     by such Section 12(b) with respect to such engine being transferred to the
     Owner Trustee; and

          (b) transfer its right, title and interest in (without recourse or
     warranty except a warranty against Lessor's Liens) and to an Engine to or
     at the direction of Lessee as contemplated by such Section 12(b).

                                   ARTICLE IV

                      RECEIPT, DISTRIBUTION AND APPLICATION
                         OF INCOME FROM THE TRUST ESTATE

          Section 4.1. DISTRIBUTION OF PAYMENTS. All Basic Rent, Supplemental
Rent, insurance proceeds and requisition, indemnity or other payments of any
kind included in the Trust Estate and any other amounts received as part of the
Trust Estate and for the application or distribution of which no provision is
made herein, shall be distributed forthwith upon receipt by the Owner Trustee in
the following order of priority: FIRST, so much of such payment as shall be
required to pay or reimburse the Owner Trustee for any fees or expenses not
otherwise paid or reimbursed as to which the Owner Trustee is entitled to be so
paid or reimbursed pursuant to the provisions hereof shall be retained by the
Owner Trustee; and SECOND, the balance, if any, shall be paid to the Owner
Participant.

          Section 4.2. METHOD OF PAYMENTS. The Owner Trustee shall make
distributions or cause distributions to be made to the Owner Participant
pursuant to this Article IV by transferring by wire transfer in immediately
available funds the amount to be distributed to such account or accounts of the
Owner Participant as it may designate from time to time by written notice to the
Owner Trustee (and the Owner Trustee shall use reasonable efforts to cause such

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funds to be transferred by wire transfer on the same day as received, but in any
case not later than the next succeeding Business Day); provided, however, that
the Owner Trustee shall use its best efforts to invest overnight, for the
benefit of the Owner Participant, in investments that would be permitted by
Section 15 of the Lease (but only to the extent such investments are available
and, if such investments are not available, then in such other investments
available to the Owner Trustee which, after consultation with the Owner
Participant, the Owner Participant shall direct), all funds not transferred by
the Owner Trustee by wire transfer on the same day as they were received.
Notwithstanding the foregoing, the Owner Trustee will, if so requested by the
Owner Participant by written notice, pay any and all amounts payable by the
Owner Trustee hereunder to the Owner Participant either (i) by crediting such
amount or amounts to an account or accounts maintained by the Owner Participant
as it may designate from time to time by written notice to the Owner Trustee, in
immediately available funds, (ii) by payment at the trust office of the Owner
Trustee (the trust office of the Owner Trustee shall be the principal corporate
trust office of the Owner Trustee at 79 South Main Street, Salt Lake City, Utah
84111, Attention: Corporate Trust Department, or the principal corporate trust
office of any successor Owner Trustee), in immediately available funds, or (iii)
by mailing an official bank check or checks in such amount or amounts payable to
the Owner Participant at such address as the Owner Participant shall have
designated in writing to the Owner Trustee.

                                    ARTICLE V

                           DUTIES OF THE OWNER TRUSTEE

          Section 5.1. NOTICE OF EVENT OF DEFAULT. If the Owner Trustee shall
have knowledge of a Default or an Event of Default, the Owner Trustee shall give
to the Owner Participant and the Lessee prompt telephonic or telecopied notice
thereof followed by prompt confirmation thereof by certified mail, postage
prepaid. Subject to the terms of Section 5.03, the Owner Trustee shall take such
action or shall refrain from taking such action, not inconsistent with the
provisions of the Operative Agreements, with respect to such Default or Event of
Default as the Owner Trustee shall be directed in writing by the Owner
Participant. For all purposes of this Trust Agreement and the Lease, the Owner
Trustee shall not be deemed to have knowledge of a Default or an Event of
Default unless notified in writing thereof in the manner and at the address set
forth in Section 10.05 or unless an officer in the Corporate Trust Department
who has responsibility for, or familiarity with, the transactions contemplated
hereunder, under the Participation Agreement or any Vice President in the
Corporate Trust Department of the Owner Trustee has actual knowledge thereof.

          Section 5.2. ACTION UPON INSTRUCTIONS. Subject in all respects to the
terms of Sections 5.01 and 5.03 and to the terms of the other Operative
Agreements, upon the written instructions at any time and from time to time of
the Owner Participant, the Owner Trustee will take such of the following actions
as may be specified in such instructions: (i) give such notice or direction or
exercise such right, remedy or power hereunder or under any of the Operative
Agreements to which the Owner Trustee is a party, or in respect of all or any
part of the Trust Estate, as shall be specified in such instructions; (ii) take
such action to preserve or protect the Trust Estate (including the discharge of
any Liens or encumbrances) as may be specified in such instructions; (iii)
approve as satisfactory to it all matters required by the terms of the Lease to
be satisfactory to the Owner Trustee, it being understood that without written
instructions of the

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Owner Participant, the Owner Trustee shall not approve any such matter as
satisfactory to it; (iv) after the expiration or earlier termination of the
Lease, convey all of the Owner Trustee's right, title and interest in and to the
Aircraft for such amount, on such terms and to such purchaser or purchasers as
shall be designated in such instructions, or retain, lease or otherwise dispose
of, or from time to time take such action with respect to, the Aircraft on such
terms as shall be set forth in such instructions or deliver the Aircraft to the
Owner Participant in accordance with such instructions; and (v) take or refrain
from taking such other action or actions as may be specified in such
instructions. In the event that the Owner Trustee is unsure of the application
of any provision of this Trust Agreement or any other agreement relating to the
transactions contemplated hereby, the Owner Trustee may request and rely upon
instructions of the Owner Participant.

          Section 5.3. INDEMNIFICATION. The Owner Trustee shall not be required
to take or refrain from taking any action under Section 5.01 (other than the
giving of notices referred to therein) or 5.02 unless the Owner Trustee shall
have been indemnified by the Owner Participant, in manner and form satisfactory
to the Owner Trustee, against any liability, cost or expense (including
reasonable counsel fees and disbursements) which may be incurred in connection
therewith; and, if the Owner Participant shall have directed the Owner Trustee
to take or refrain from taking any such action, the Owner Participant agrees to
furnish such indemnity as shall be required and in addition to pay the
reasonable fees and charges of the Owner Trustee for the services performed or
to be performed by it pursuant to such direction. The Owner Trustee shall not be
required to take any action under Section 5.01 or 5.02 if the Owner Trustee
shall reasonably determine, or shall have been advised by counsel, that such
action is contrary to the terms of any of the Operative Agreements to which the
Owner Trustee is a party, or is otherwise contrary to Applicable Law.

          Section 5.4. NO DUTIES EXCEPT AS SPECIFIED IN TRUST AGREEMENT OR
INSTRUCTIONS.
          The Owner Trustee shall not have any duty or obligation to manage,
control, use, sell, dispose of or otherwise deal with the Aircraft or any other
part of the Trust Estate, or otherwise to take or refrain from taking any action
under, or in connection with any of the Operative Agreements to which the Owner
Trustee is a party, except as expressly required by the terms of any of the
Operative Agreements to which the Owner Trustee is a party, or as expressly
provided by the terms hereof or in written instructions from the Owner
Participant received pursuant to the terms of Section 5.01 or 5.02, and no
implied duties or obligations shall be read into this Trust Agreement or any of
the Operative Agreements to which the Owner Trustee is a party against the Owner
Trustee. The Owner Trustee nevertheless agrees that it will, in its individual
capacity and at its own cost and expense (but without any right of indemnity in
respect of any such cost or expense under Section 7.01) promptly take such
action as may be necessary duly to discharge and satisfy in full (i) all
Lessor's Liens attributable to the Owner Trustee in its individual capacity,
(ii) any Liens (other than Lessor's Liens attributable to it in its individual
capacity) created as a result of its breach of any of its obligations under this
Trust Agreement (subject to the limitations on the liability of the Owner
Trustee in its individual capacity set forth in Section 6.01) on any part of the
Trust Estate, or on any properties of the Owner Trustee assigned, pledged or
mortgaged as part of the Trust Estate, which arise from acts of the Owner
Trustee in its individual capacity, the rights of Lessee under the Lease and the
rights of the Owner Participant hereunder, and (iii) any other Liens or
encumbrances attributable to the Owner Trustee in its individual capacity on any
part of the Trust Estate which result from claims

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against the Owner Trustee in its individual capacity unrelated to the ownership
of the Aircraft, the administration of the Trust Estate or the transactions
contemplated by the Operative Agreements.

          Section 5.5. NO ACTION EXCEPT UNDER SPECIFIED DOCUMENTS OR
INSTRUCTIONS.
          The Owner Trustee shall have no power or authority to, and the Owner
Trustee agrees that it will not, manage, control, use, sell, dispose of or
otherwise deal with the Aircraft or any other part of the Trust Estate except
(i) as expressly required by the terms of any of the Operative Agreements to
which the Owner Trustee is a party, (ii) as expressly provided by the terms
hereof, or (iii) as expressly provided in written instructions from the Owner
Participant pursuant to Section 5.01 or 5.02.

                                   ARTICLE VI

                                THE OWNER TRUSTEE

          Section 6.1. ACCEPTANCE OF TRUSTS AND DUTIES. WFB accepts the trusts
hereby created and agrees to perform the same but only upon the terms hereof
applicable to it. WFB also agrees to receive and disburse all monies received by
it constituting part of the Trust Estate upon the terms hereof. WFB shall not be
answerable or accountable under any circumstances, except for (i) its own
willful misconduct or gross negligence, (ii) its performance of the terms of the
last sentence of Section 5.04, (iii) its failure to use ordinary care in
receiving or disbursing funds or to comply with the first sentence of Section
6.08, (iv) liabilities that may result from the inaccuracy of any representation
or warranty of the Owner Trustee in its individual capacity (or from the failure
by the Owner Trustee in its individual capacity to perform any covenant made in
its individual capacity) in Section 6.03 or in any of the Operative Agreements
to which the Owner Trustee is a party, (v) taxes, fees or other charges on,
based on or measured by any fees, commissions or other compensation received by
WFB as compensation for its services rendered as the Owner Trustee, and (vi) its
failure (in its individual capacity or as Owner Trustee) to use ordinary care in
connection with its obligations to invest funds pursuant to Section 15 of the
Lease or Section 4.02 hereof; PROVIDED, HOWEVER, that the failure to act or
perform in the absence of instructions after the Owner Trustee has requested
instructions from the Owner Participant pursuant to the last sentence of
Section 5.02 shall not constitute willful misconduct or gross negligence for
purposes of clause (i) of this Section 6.01.

          Section 6.2. ABSENCE OF CERTAIN DUTIES. Except in accordance with
written instructions furnished pursuant to Sections 5.01 and 5.02 and except as
provided in, and without limiting the generality of, Sections 3.01, 5.04 and
5.05 and the last sentence of Section 8.01(b), the Owner Trustee shall have no
duty (i) to see to any registration of the Aircraft or any recording or filing
of the Lease, this Trust Agreement, any financing or continuation statement or
of any supplement to any thereof or to see to the maintenance of any such
registration, rerecording or refiling, except that of Owner Trustee to comply
with the FAA reporting requirements set forth in 14 C.F.R. Section 47.45 and 14
C.F.R. Section 47.51 or any successor provisions, and that the Owner Trustee
shall upon written request furnished by Lessee take such action as may be
required of the Owner Trustee to maintain the registration of the Aircraft in
the name of the Owner Trustee under the Act or, to the extent the Aircraft is
registered in a country other than the United States of America pursuant to
Section 4.02 of the Participation Agreement, other

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Applicable Law, and to the extent that information for that purpose is supplied
by Lessee pursuant to any of the Operative Agreements, complete and timely
submit any and all reports relating to the Aircraft which may from time to time
be required by the FAA or any government or governmental authority having
jurisdiction, (ii) to see to any insurance on the Aircraft or to effect or
maintain any such insurance, whether or not Lessee shall be in default with
respect thereto, (iii) to see to the payment or discharge of any tax, assessment
or other governmental charge or any Lien or encumbrance of any kind owing with
respect to, assessed or levied against any part of the Trust Estate except as
provided by Section 5.04 hereof or Section 5.03(b) of the Participation
Agreement, (iv) to confirm or verify any financial statements of Lessee or (v)
to inspect the Aircraft or the books and records of Lessee with respect to the
Aircraft. Notwithstanding the foregoing, the Owner Trustee will furnish to Owner
Participant, promptly upon receipt thereof, duplicates or copies of all reports,
notices, requests, demands, certificates, financial statements and other
instruments furnished to Owner Trustee under the Lease or any other Operative
Agreement except to the extent to which a Responsible Officer of Owner Trustee
reasonably believes (and confirms by telephone call with Owner Participant) that
duplicates or copies thereof have already been furnished to Owner Participant by
some other Person.

          Section 6.3. NO REPRESENTATIONS OR WARRANTIES AS TO CERTAIN MATTERS.
THE OWNER TRUSTEE IN ITS INDIVIDUAL CAPACITY OR AS THE OWNER TRUSTEE DOES NOT
MAKE AND SHALL NOT BE DEEMED TO HAVE MADE (a) ANY REPRESENTATION OR WARRANTY,
EXPRESS OR IMPLIED, AS TO THE TITLE, VALUE, CONDITION, DESIGN, OPERATION,
MERCHANTABILITY OR FITNESS FOR USE FOR A PARTICULAR PURPOSE OF THE AIRCRAFT, ANY
ENGINE THEREOF, ABSENCE OF LATENT OR OTHER DEFECTS (WHETHER OR NOT DISCOVERABLE)
OR ANY OTHER REPRESENTATION OR WARRANTY WITH RESPECT TO THE AIRCRAFT OR ANY
ENGINE WHATSOEVER, except that the Owner Trustee in its individual capacity
warrants that on the Delivery Date the Owner Trustee shall have received and
shall hold whatever title to the Aircraft was conveyed to it by Seller free and
clear of Lessor's Liens attributable to the Owner Trustee in its individual
capacity, shall be in compliance with the last sentence of Section 5.04 hereof
and that the Aircraft shall during the Lease Term be free of Lessor's Liens
attributable to it in its individual capacity, or (b) any representation or
warranty as to the validity, legality or enforceability of this Trust Agreement
or any other Operative Agreement to which the Owner Trustee in its individual
capacity or as Owner Trustee is a party, or any other document or instrument, or
as to the correctness of any statement contained in any thereof except to the
extent that any such statement is expressly made herein or therein as a
representation by the Owner Trustee in its individual capacity and except that
the Owner Trustee in its individual capacity hereby represents and warrants that
it has all corporate power and authority to execute, deliver and perform this
Trust Agreement and that this Trust Agreement has been, and (assuming the due
authorization, execution and delivery of the Trust Agreement by the Owner
Participant) the other Operative Agreements to which the Owner Trustee is a
party have been (or at the time of execution and delivery of any such instrument
by the Owner Trustee hereunder or pursuant to the terms of the Participation
Agreement that such an instrument will be) duly executed and delivered by one of
its officers who is or will be, as the case may be, duly authorized to execute
and deliver such instruments on behalf of the Owner Trustee and that this Trust
Agreement has been duly authorized, executed and delivered by WFB and
constitutes the legal, valid and binding obligation of WFB enforceable against
it in accordance with its terms, except as such terms may be limited by
bankruptcy, insolvency, reorganization, moratorium or

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other similar laws affecting the rights of creditors generally and by general
principles of equity, regardless of whether considered in a proceeding in equity
or at law.

          Section 6.4. NO SEGREGATION OF MONIES REQUIRED; INVESTMENT THEREOF.
Monies received by the Owner Trustee hereunder need not be segregated in any
manner except to the extent required by Applicable Law, and may be deposited
under such general conditions as may be prescribed by Applicable Law, and shall
be invested as provided in Section 4.02 hereof or Section 15 of the Lease.

          Section 6.5. RELIANCE UPON CERTIFICATES, COUNSEL AND AGENTS. The Owner
Trustee shall incur no liability to anyone in acting in reliance upon any
signature, instrument, notice, resolution, request, consent, order, certificate,
report, opinion, bond or other document or paper reasonably believed by it to be
genuine and reasonably believed by it to be signed by the proper party or
parties. Unless other evidence in respect thereof is specifically prescribed
herein, any request, direction, order or demand of the Owner Participant or
Lessee mentioned herein or in any of the other Operative Agreements to which the
Owner Trustee is a party shall be sufficiently evidenced by written instruments
signed by a person purporting to be a Responsible Officer of the Owner
Participant or Lessee, as the case may be. The Owner Trustee may accept a copy
of a resolution of the Board of Directors of Lessee or the Owner Participant, as
the case may be, certified by the Secretary or an Assistant Secretary of Lessee
or the Owner Participant, as the case may be, as duly adopted and in full force
and effect, as conclusive evidence that such resolution has been duly adopted by
said Board and that the same is in full force and effect. As to any fact or
matter the manner of ascertainment of which is not specifically described
herein, the Owner Trustee may, absent actual knowledge to the contrary, for all
purposes hereof rely on a certificate signed by a Responsible Officer of Lessee
or the Owner Participant, as the case may be, as to such fact or matter, and
such certificate shall constitute full protection to the Owner Trustee for any
action taken or omitted to be taken by it in good faith in reliance thereon.

          In the administration of the trusts hereunder, the Owner Trustee may
exercise its powers and perform its duties hereunder directly or through agents
or attorneys and the Owner Trustee shall not be liable for the default or
misconduct of any agents or attorneys selected by it with reasonable care. In
the administration of the trusts hereunder, the Owner Trustee may consult with
counsel, accountants and other skilled persons and the Owner Trustee shall not
be liable for anything done, suffered or omitted in good faith by it in
accordance with the advice or opinion of any such counsel, accountants or other
skilled persons selected by it with reasonable care.

          Section 6.6. NOT ACTING IN INDIVIDUAL CAPACITY. In acting hereunder,
the Owner Trustee acts solely as trustee and not in its individual capacity
except as otherwise expressly provided herein; and, except as may be otherwise
expressly provided in this Trust Agreement, including without limitation,
Section 6.01, the Lease or the Participation Agreement, all Persons having any
claim against the Owner Trustee by reason of the transactions contemplated
hereby shall look only to the Trust Estate for payment or satisfaction thereof.

          Section 6.7. FEES; COMPENSATION. Except as provided in Section 5.03 or
7.01, the Owner Trustee agrees that it shall have no right against the Owner
Participant or the Trust Estate for any fee as compensation for its services
hereunder.

                                       9
<Page>

          Section 6.8. TAX RETURNS. The Owner Trustee shall be responsible for
the keeping of all appropriate books and records relating to the receipt and
disbursement of all monies under this Trust Agreement or any agreement
contemplated hereby. The Owner Trustee agrees, without expense to the Owner
Participant, to file an application with the Internal Revenue Service for a
taxpayer identification number with respect to the trust created by this Trust
Agreement. The Owner Participant shall be responsible for causing to be prepared
and filed all income tax returns required to be filed by the Owner Participant.
The Owner Trustee shall be responsible for causing to be prepared, at the
request of the Owner Participant and the expense of the Lessee, all income tax
returns required to be filed with respect to the trust created hereby and shall
execute and file such returns; provided, however the Owner Trustee shall send a
completed copy of such return to the Owner Participant not more than 60 nor less
than 30 days prior to the due date of the return provided that the Owner Trustee
shall have timely received all necessary information to complete and deliver to
the Owner Participant such return. The Owner Participant or the Owner Trustee,
as the case may be, upon request, will furnish the Owner Trustee or the Owner
Participant, as the case may be, with all such information as may be reasonably
required from the Owner Participant or the Owner Trustee, as the case may be, in
connection with the preparation of such income tax returns.

          Section 6.9. FIXED INVESTMENT TRUST. Notwithstanding anything herein
to the contrary, the Owner Trustee shall not be authorized and shall have no
power to "vary the investment" of the Owner Participant within the meaning of
section 301.7701-4(c) of the Treasury Regulations.

                                   ARTICLE VII

                      INDEMNIFICATION OF THE OWNER TRUSTEE
                            BY THE OWNER PARTICIPANT

          Section 7.1. THE OWNER PARTICIPANT TO INDEMNIFY THE OWNER TRUSTEE. The
Owner Participant hereby agrees, whether or not any of the transactions
contemplated hereby shall be consummated, to assume liability for, and does
hereby indemnify, protect, save, defend and hold harmless the Owner Trustee in
its individual capacity, and its successors, assigns (but not security assigns),
directors, officers, representatives, agents, employees and servants, from and
against any and all liabilities, obligations, losses, damages, penalties, taxes
(excluding any taxes payable by the Owner Trustee on or measured by any
compensation received by the Owner Trustee for its services hereunder), claims,
actions, suits, costs, expenses or disbursements (including, without limitation,
reasonable legal fees, but excluding internal costs and expenses such as
salaries and overhead) and expenses of any kind and nature whatsoever which may
be imposed on, incurred by or asserted against the Owner Trustee in its
individual capacity (whether or not also indemnified against by Lessee under the
Lease or under the Participation Agreement or also indemnified against by any
other Person; PROVIDED that Owner Participant shall be subrogated to the rights
of Owner Trustee against Lessee or any other indemnitor) in any way relating to
or arising out of this Trust Agreement or any of the other Operative Agreements
or the enforcement of any of the terms of any thereof, or in any way relating to
or arising out of the manufacture, purchase, acceptance, nonacceptance,
rejection, ownership, delivery, lease, possession, use, operation, condition,
sale, return or other disposition of the Airframe, any Engine or any Part of the
foregoing (including, without limitation, latent and other defects,

                                       10
<Page>

whether or not discoverable, and any claim for patent, trademark or copyright
infringement), or in any way relating to or arising out of the administration of
the Trust Estate or the action or inaction of the Owner Trustee hereunder,
except (a) in the case of willful misconduct or gross negligence on the part of
the Owner Trustee either as trustee or in its individual capacity in the
performance or nonperformance of its duties hereunder or under any of the other
Operative Agreements to which it is a party or (b) those resulting from the
inaccuracy of any representation or warranty of the Owner Trustee in its
individual capacity (or from the failure of the Owner Trustee in its individual
capacity to perform any covenant) in Section 6.03, or in any of the Operative
Agreements, or (c) those arising or resulting from any of the matters described
in the last sentence of Section 6.01, or (d) those resulting from its failure to
perform the terms of the last sentence of Section 5.04 hereof or from its
failure to use ordinary care in the receipt and disbursement of funds or in
connection with its obligation to invest funds pursuant to Section 15 of the
Lease or Section 4.02 hereof or in compliance with the first Section of Section
6.08, or (e) any liability on the part of Owner Trustee arising out of its
negligence or willful or negligent misconduct in connection with its obligations
under Section 5.01, 6.08 or 8.02 hereof, or (f) those arising under any
circumstances or upon any terms where Lessee would not have been required to
indemnify Owner Trustee, in its individual capacity, pursuant to Section 6.01 or
7.01 of the Participation Agreement disregarding for purposes of this Section
7.01, Sections 6.01(ii), 6.01(v) and 7.01(b)(ii) of the Participation Agreement;
PROVIDED, that before asserting its right to indemnification, if any, pursuant
to this Section 7.01, Owner Trustee shall first demand its corresponding right
to indemnification pursuant to Section 6.01 or 7.01 of the Participation
Agreement (but need not exhaust any or all remedies available thereunder). The
indemnities contained in this Section 7.01 extend to the Owner Trustee only in
its individual capacity and shall not be construed as indemnities of the Trust
Estate. The indemnities contained in this Section 7.01 shall survive the
termination of this Trust Agreement and the resignation or removal of the Owner
Trustee. In addition, if necessary, the Owner Trustee shall be entitled to
indemnification from the Trust Estate for any liability, obligation, loss,
damage, penalty, tax, claim, action, suit, cost, expense or disbursement
indemnified against pursuant to this Section 7.01 to the extent not reimbursed
by Lessee, the Owner Participant or others, but without releasing any of them
from their respective agreements of reimbursement.

                                  ARTICLE VIII

                      SUCCESSOR OWNER TRUSTEES; CO-TRUSTEES

          Section 8.1. RESIGNATION OF THE OWNER TRUSTEE; APPOINTMENT OF
SUCCESSOR. (a) RESIGNATION OR REMOVAL. The Owner Trustee or any successor Owner
Trustee (i) shall resign if required to do so pursuant to Section 5.02(b) of the
Participation Agreement and (ii) may resign at any time without cause by giving
at least 60 days prior written notice to the Owner Participant and Lessee, such
resignation to be effective upon the acceptance of appointment by the successor
Owner Trustee under Section 8.01(b). In addition, the Owner Participant may at
any time remove the Owner Trustee, or revoke the trusts created by this Trust
Agreement, in either case with or without cause by a notice in writing delivered
to the Owner Trustee and Lessee. Any such removal shall be effective upon the
acceptance of appointment by the successor Owner Trustee under Section 8.01(b).
In the case of the resignation or removal of the Owner Trustee, the Owner
Participant may appoint a successor Owner Trustee by an instrument in writing.
If a successor Owner Trustee shall not have been appointed within 30 days after
such notice of

                                       11
<Page>

resignation or removal, the Owner Trustee may apply to any court of competent
jurisdiction to appoint a successor Owner Trustee to act until such time, if
any, as a successor shall have been appointed as above provided. Any successor
Owner Trustee so appointed by such court shall immediately and without further
act be superseded by any successor Owner Trustee appointed as above provided
within one year from the date of the appointment by such court.

          (b) EXECUTION AND DELIVERY OF DOCUMENTS, ETC. Any successor Owner
Trustee, however appointed, shall execute and deliver to the predecessor Owner
Trustee, with a copy to Owner Participant and Lessee, an instrument accepting
such appointment and assuming the obligations of Owner Trustee, in its
individual capacity and as Owner Trustee, under the Operative Agreements to
which Owner Trustee is a party, and thereupon such successor Owner Trustee,
without further act, shall become vested with all the estates, properties,
rights, powers, duties and trusts of the predecessor Owner Trustee in the trust
hereunder with like effect as if originally named the Owner Trustee herein; but
nevertheless, upon the written request of such successor Owner Trustee, such
predecessor Owner Trustee shall execute and deliver an instrument transferring
to such successor Owner Trustee upon the trusts herein expressed, all the
estates, properties, rights, powers and trusts of such predecessor Owner
Trustee, and such predecessor Owner Trustee shall duly assign, transfer, deliver
and pay over to such successor Owner Trustee all monies or other property then
held by such predecessor Owner Trustee upon the trusts herein expressed. Upon
the appointment of any successor Owner Trustee hereunder, the predecessor Owner
Trustee will complete, execute and deliver to the successor Owner Trustee such
documents as are necessary to cause registration of the Aircraft included in the
Trust Estate to be transferred upon the records of the FAA or other governmental
authority having jurisdiction, into the name of the successor Owner Trustee.

          (c) QUALIFICATION. Any successor Owner Trustee, however appointed,
shall be a Citizen of the United States, shall be qualified to act as a trustee
in Utah (if the trust created hereby is to remain in such state) and shall also
be a bank or trust company organized under the laws of the United States of
America or any state thereof having a combined capital and surplus of at least
$100,000,000, if there be such an institution willing, able and legally
qualified to perform the duties of the Owner Trustee hereunder upon reasonable
and customary terms.

          (d) MERGER, ETC. Any corporation into which the Owner Trustee may be
merged or converted or with which it may be consolidated, or any corporation
resulting from any merger, conversion or consolidation to which the Owner
Trustee shall be a party, or any corporation to which substantially all the
corporate trust business of the Owner Trustee may be transferred, shall, subject
to the terms of Section 8.01(c), be the Owner Trustee hereunder without further
act.

          Section 8.2. CO-TRUSTEES AND SEPARATE TRUSTEES. If at any time or
times it shall be necessary or prudent in order to conform to any Applicable Law
of any jurisdiction in which all or any part of the Trust Estate is located, or
the Owner Trustee shall be advised by counsel that it is so necessary or prudent
in the interest of the Owner Participant or the Owner Trustee, or the Owner
Trustee shall have been directed to do so by the Owner Participant, the Owner
Trustee and the Owner Participant shall execute and deliver an agreement
supplemental hereto and all other instruments and agreements necessary or proper
to constitute another bank or trust company or one or more Persons (any and all
of which shall be a Citizen of the United States)

                                       12
<Page>

approved by the Owner Trustee and the Owner Participant, either to act as
co-trustee or co-trustees, jointly with the Owner Trustee, or to act as separate
trustee or trustees hereunder (any such co-trustee or separate trustee being
herein sometimes referred to as an "additional trustee"). In the event the Owner
Participant shall not have joined in the execution of such agreements
supplemental hereto within ten days after the receipt of a written request from
the Owner Trustee so to do, the Owner Trustee may act under the foregoing
provisions of this Section 8.02 without the concurrence of the Owner
Participant; and the Owner Participant hereby appoints the Owner Trustee its
agent and attorney-in-fact to act for it under the foregoing provisions of this
Section 8.02 in either of such contingencies.

          Every additional trustee hereunder shall, to the extent permitted by
Applicable Law, be appointed and act, and the Owner Trustee and its successors
shall act, subject to the following provisions and conditions:

          (a) all powers, duties, obligations and rights conferred upon the
     Owner Trustee in respect of the custody, control and management of monies,
     the Aircraft or documents authorized to be delivered hereunder or under the
     Participation Agreement shall be exercised solely by the corporation
     designated as the Owner Trustee in the first paragraph of this Trust
     Agreement, or its successors as the Owner Trustee hereunder;

          (b) all other rights, powers, duties and obligations conferred or
     imposed upon the Owner Trustee and any limitations thereon shall be
     conferred or imposed upon and exercised or performed by the corporation
     designated as the Owner Trustee in the first paragraph of this Trust
     Agreement or its successors as the Owner Trustee, and such additional
     trustee or trustees jointly, except to the extent that under any Applicable
     Law of any jurisdiction in which any particular act or acts are to be
     performed (including the holding of title to the Trust Estate), the Owner
     Trustee shall be incompetent or unqualified to perform such act or acts, in
     which event such rights, powers, duties and obligations shall be exercised
     and performed by such additional trustee or trustees;

          (c) no power given to, or which it is provided hereby may be exercised
     by, any such additional trustee or trustees shall be exercised hereunder by
     such additional trustee or trustees, except jointly with, or with the
     consent in writing of, the corporation designed as the Owner Trustee in
     this Trust Agreement or its successor as the Owner Trustee, anything herein
     contained to the contrary notwithstanding;

          (d) no trustee hereunder shall be personally liable by reason of any
     act or omission of any other trustee hereunder; and

          (e) the Owner Participant, at any time, by an instrument in writing
     may remove any such additional trustee. In the event that the Owner
     Participant shall not have joined in the execution of any such instrument
     within ten days after the receipt of a written request from the Owner
     Trustee so to do, the Owner Trustee shall have the power to remove any such
     additional trustee without the concurrence of the Owner Participant; and
     the Owner Participant hereby appoints the Owner Trustee its agent and
     attorney-in-fact to act for it in such connection in such contingency.

                                       13
<Page>

          In case any separate trustee under this Section 8.02 shall die, become
incapable of acting, resign or be removed, the title to the Trust Estate and all
rights and duties of such separate trustee shall, so far as permitted by
Applicable Law, vest in and be exercised by Owner Trustee, without the
appointment of a successor to such separate trustee.

                                   ARTICLE IX

                  SUPPLEMENTS AND AMENDMENTS TO TRUST AGREEMENT
                               AND OTHER DOCUMENTS

          Section 9.1. SUPPLEMENTS AND AMENDMENTS. At any time and from time to
time, upon the written request of the Owner Participant, (i) the Owner Trustee,
together with the Owner Participant, shall execute a supplement to this Trust
Agreement for the purpose of adding provisions to, or changing or eliminating
provisions of, this Trust Agreement (except Section 10.11) as specified in such
request, and (ii) the Owner Trustee shall enter into such written amendment of
or supplement to any other Operative Agreement to which the Owner Trustee is a
party as Lessee may agree to and as may be specified in such request, or execute
and deliver such written waiver or modification of or consent under the terms of
any such Operative Agreement as Lessee may agree to and as may be specified in
such request.

          Section 9.2. DISCRETION AS TO EXECUTION OF DOCUMENTS. If in the
opinion of the Owner Trustee any document required to be executed pursuant to
the terms of Section 9.01 adversely affects any right, duty, immunity or
indemnity in favor of the Owner Trustee hereunder or under any other Operative
Agreement to which the Owner Trustee is a party, the Owner Trustee may in its
discretion decline to execute such document unless Owner Trustee is furnished
with indemnification from Lessee or any other party upon terms and in amounts
reasonably satisfactory to Owner Trustee to protect the Trust Estate and Owner
Trustee against any and all liabilities, costs and expenses arising out of the
execution of such documents.

          Section 9.3. ABSENCE OF REQUIREMENTS AS TO FORM. It shall not be
necessary for any written request furnished pursuant to Section 9.01 to specify
the particular form of the proposed documents to be executed pursuant to such
Section, but it shall be sufficient if such request shall indicate the substance
thereof.

          Section 9.4. DISTRIBUTION OF DOCUMENTS. Promptly after the execution
by the Owner Trustee of any document entered into pursuant to Section 9.01, the
Owner Trustee shall mail, by certified mail, postage prepaid, a conformed copy
thereof to the Owner Participant, but the failure of the Owner Trustee to mail
such conformed copy shall not impair or affect the validity of such document.

                                    ARTICLE X

                                  MISCELLANEOUS

          Section 10.1. TERMINATION OF TRUST AGREEMENT. This Trust Agreement and
the trusts created hereby shall terminate and this Trust Agreement shall be of
no further force or effect upon the earliest of (a) the later of (x) the sale or
other final disposition by the Owner

                                       14
<Page>

Trustee of all property constituting part of the Trust Estate and the final
distribution by the Owner Trustee of all monies or other property or proceeds
constituting part of the Trust Estate in accordance with Article IV hereof,
provided that at such time Lessee shall have fully complied with all of the
terms of the Participation Agreement and the Lease, and (y) the expiration or
termination of the Lease in accordance with its terms or (b) twenty-one (21)
years less one day after the death of the last survivor of all of the
descendants of the grandparents of Joseph P. Kennedy living on the date of the
earliest execution of this Trust Agreement by either party hereto, otherwise
this Trust Agreement and the trusts created hereby shall continue in full force
and effect in accordance with the terms hereof.

          Notwithstanding the foregoing, this Trust Agreement and trust created
hereby shall terminate and the Trust Estate shall be distributed to the Owner
Participant, and this Trust Agreement shall be of no further force and effect,
upon the election of the Owner Participant by notice to the Owner Trustee, if
such notice shall be accompanied by the written agreement (in form and substance
satisfactory to the Owner Trustee) of the Owner Participant assuming all
obligations of the Owner Trustee under or contemplated by the Operative
Agreements or incurred by it as trustee hereunder and releasing the Owner
Trustee therefrom; provided, however, that such notice may be given only after
the Lease shall no longer be in effect.

          Section 10.2. THE OWNER PARTICIPANT HAS NO LEGAL TITLE IN TRUST
ESTATE. The Owner Participant does not have legal title to any part of the Trust
Estate. No transfer, by operation of law or otherwise, of any right, title and
interest of the Owner Participant in and to the Trust Estate hereunder shall
operate to terminate this Trust Agreement or the trusts hereunder or entitle any
successors or transferees of the Owner Participant to an accounting or to the
transfer of legal title to any part of the Trust Estate.

          Section 10.3. ASSIGNMENT, SALE, ETC., OF AIRCRAFT. Any assignment,
sale, transfer or other conveyance of the Aircraft, any Engine, any Part or any
interest therein by the Owner Trustee made pursuant to the terms hereof or of
the Lease or the Participation Agreement shall bind the Owner Participant and
shall be effective to transfer or convey all right, title and interest of the
Owner Trustee and the Owner Participant in and to the Aircraft, such Engine,
such Part or interest therein. No purchaser or other grantee shall be required
to inquire as to the authorization, necessity, expediency or regularity of such
assignment, sale, transfer or conveyance or as to the application of any sale or
other proceeds with respect thereto by the Owner Trustee.

          Section 10.4. TRUST AGREEMENT FOR BENEFIT OF CERTAIN PARTIES ONLY.
Except for the terms of Section 4.01, Articles V and VIII, Sections 9.01, 10.01
and 10.03 hereof, nothing herein, whether express or implied, shall be construed
to give any Person other than the Owner Trustee, WFB, the Lessee and the Owner
Participant any legal or equitable right, remedy or claim under or in respect of
this Trust Agreement; but this Trust Agreement shall be held to be for the sole
and exclusive benefit of the Owner Trustee, WFB, the Lessee and the Owner
Participant.

          Section 10.5. NOTICES. Unless otherwise expressly specified or
permitted by the terms hereof, all notices shall be given in the manner set
forth in Section 12.01 of the Participation Agreement.

                                       15
<Page>

          Section 10.6. SEVERABILITY. Any provision hereof which is prohibited
or unenforceable in any jurisdiction shall, as to such jurisdiction, be
ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.

          Section 10.7. WAIVERS, ETC. No term or provision hereof may be
changed, waived, discharged or terminated orally, but only by an instrument in
writing entered into in compliance with the terms of Article IX hereof; and any
waiver of the terms hereof shall be effective only in the specified instance and
for the specific purpose given.

          Section 10.8. COUNTERPARTS. This Trust Agreement may be executed by
the parties hereto in separate counterparts, each of which when so executed and
delivered shall be an original, but all such counterparts shall together
constitute but one and the same instrument.

          Section 10.9. BINDING EFFECT, ETC. All covenants and agreements
contained herein shall be binding upon, and inure to the benefit of, the Owner
Trustee and its successors and permitted assigns, and the Owner Participant, its
successors and permitted assigns. Any request, notice, direction, consent,
waiver or other instrument or action by the Owner Participant or Owner Trustee
shall bind their respective successors and permitted assigns.

          Section 10.10. HEADINGS; REFERENCES. The headings of the various
Articles and Sections herein are for convenience of reference only and shall not
define or limit any of the terms or provisions hereof.

          Section 10.11. GOVERNING LAW. (a) THIS TRUST AGREEMENT SHALL IN ALL
RESPECTS BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE
OF UTAH, INCLUDING ALL MATTERS OF CONSTRUCTION, VALIDITY AND PERFORMANCE.

          (b) TO THE EXTENT PERMITTED BY APPLICABLE LAW, EACH PARTY HERETO
HEREBY IRREVOCABLY AGREES, ACCEPTS AND SUBMITS ITSELF TO THE NON-EXCLUSIVE
JURISDICTION OF THE COURTS OF THE STATE OF NEW YORK IN THE CITY AND COUNTY OF
NEW YORK AND OF THE UNITED STATES FOR THE SOUTHERN DISTRICT OF NEW YORK, IN
CONNECTION WITH ANY LEGAL ACTION, SUIT OR PROCEEDING WITH RESPECT TO ANY MATTER
RELATING TO OR ARISING OUT OF OR IN CONNECTION WITH THIS TRUST AGREEMENT.

          (c) TO THE EXTENT PERMITTED BY APPLICABLE LAW, EACH PARTY HERETO
HEREBY IRREVOCABLY CONSENTS AND AGREES THAT THE SERVICE OF ANY AND ALL LEGAL
PROCESS, SUMMONS NOTICES AND DOCUMENTS OF ANY OF THE AFOREMENTIONED COURTS IN
ANY SUCH SUIT, ACTION OR PROCEEDING MAY BE MADE BY MAILING COPIES THEREOF BY
REGISTERED OR CERTIFIED MAIL, POSTAGE PREPAID, AT THE ADDRESS REFERRED TO IN
SECTION 10.05. EACH PARTY HERETO HEREBY AGREES THAT SERVICE UPON IT IN
ACCORDANCE WITH THIS SECTION 10.11(c) SHALL CONSTITUTE VALID AND EFFECTIVE
PERSONAL SERVICE UPON SUCH PARTY.

                                       16
<Page>

          (d) EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES, TO THE EXTENT
PERMITTED BY APPLICABLE LAW, AND AGREES NOT TO ASSERT, BY WAY OF MOTION, AS A
DEFENSE, OR OTHERWISE, IN ANY LEGAL ACTION OR PROCEEDING BROUGHT HEREUNDER IN
ANY OF THE ABOVE-NAMED COURTS, THAT SUCH ACTION OR PROCEEDING IS BROUGHT IN AN
INCONVENIENT FORUM, THAT VENUE FOR THE ACTION OR PROCEEDING IS IMPROPER OR THAT
THIS TRUST AGREEMENT OR ANY OTHER OPERATIVE AGREEMENT MAY NOT BE ENFORCED IN OR
BY SUCH COURTS.

          (e) TO THE EXTENT PERMITTED BY APPLICABLE LAW, EACH PARTY HERETO
HEREBY WAIVES ITS RESPECTIVE RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF
ACTION IN ANY COURT IN ANY JURISDICTION BASED UPON OR ARISING OUT OF OR RELATING
TO THIS TRUST AGREEMENT.

          Section 10.12. ADMINISTRATION OF TRUST. The principal place of
administration of the trust created by this Trust Agreement shall be in the
State of Utah.

            [The remainder of this page is intentionally left blank.]

                                       17
<Page>

          IN WITNESS WHEREOF, the parties hereto have caused this Trust
Agreement to be duly executed by their respective officers thereunto duly
authorized as of the day and year first above written.

                               SILVERMINE RIVER FINANCE TWO, INC.

                               By:
                                    ------------------------------------
                                    Name:
                                    Title:

                               WELLS FARGO BANK NORTHWEST, NATIONAL ASSOCIATION

                               By:
                                    ------------------------------------
                                    Name:
                                    Title:

                                       18

<Page>

NOTE TO EXHIBIT 10.28

The 12 additional Trust Agreements are substantially identical in all material
respects to the filed Trust Agreement except as follows:

<Table>
<Caption>

- ------------------------------------- ----------------------------------- -----------------------------------
            TAIL NUMBER                          CLOSING DATE                     OWNER-PARTICIPANT

- ------------------------------------- ----------------------------------- -----------------------------------
                                                                    
N289SK                                           July, 2001                General Electric Capital Corp.
- ------------------------------------- ----------------------------------- -----------------------------------
N290SK                                           July, 2001                General Electric Capital Corp.
- ------------------------------------- ----------------------------------- -----------------------------------
N291SK                                          August, 2001               General Electric Capital Corp.
- ------------------------------------- ----------------------------------- -----------------------------------
N292SK                                          August, 2001               General Electric Capital Corp.
- ------------------------------------- ----------------------------------- -----------------------------------
N293SK                                         September, 2001             General Electric Capital Corp.
- ------------------------------------- ----------------------------------- -----------------------------------
N294SK                                         September, 2001             General Electric Capital Corp.
- ------------------------------------- ----------------------------------- -----------------------------------
N295SK                                          November, 2001             Silvermine River Finance Two, Inc.
- ------------------------------------- ----------------------------------- -----------------------------------
N297SK                                          November, 2001             Silvermine River Finance Two, Inc.
- ------------------------------------- ----------------------------------- -----------------------------------
N298SK                                          October, 2001              Silvermine River Finance Two, Inc.
- ------------------------------------- ----------------------------------- -----------------------------------
N299SK                                          November, 2001             Silvermine River Finance Two, Inc.
- ------------------------------------- ----------------------------------- -----------------------------------
N370SK                                          November, 2001             Silvermine River Finance Two, Inc.
- ------------------------------------- ----------------------------------- -----------------------------------
N371SK                                          November, 2001             Silvermine River Finance Two, Inc.
- ------------------------------------- ----------------------------------- -----------------------------------

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

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

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

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

- ------------------------------------- ----------------------------------- -----------------------------------
</Table>