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                             TRUST AGREEMENT [____]

                          Dated as of [______________]


                                     Between


                           [_________________________]

                                       and


                      WELLS FARGO BANK NORTHWEST, NATIONAL
                                   ASSOCIATION


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


                    One Boeing Model [_____________]Aircraft
                 Bearing Manufacturer's Serial No. [___________]








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                                TABLE OF CONTENTS
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SECTION 1.    DEFINITIONS.................................................................................1

SECTION 2.    DECLARATION OF TRUST........................................................................1

SECTION 3.    AUTHORIZATION; CONDITIONS PRECEDENT.........................................................1

      3.1     Authorization...............................................................................1
      3.2     Conditions Precedent........................................................................2

SECTION 4.    RECEIPT, DISTRIBUTION AND APPLICATION OF INCOME FROM THE TRUST ESTATE.......................3

      4.1     Payments from Trust Estate Only.............................................................3
      4.2     Distribution of Payments....................................................................3
      4.3     Method of Payments..........................................................................4

SECTION 5.    DUTIES OF OWNER TRUSTEE.....................................................................5

      5.1     Notice of Event of Default..................................................................5
      5.2     Action upon Instructions....................................................................5
      5.3     Limitations on Duties.......................................................................6
      5.4     No Duties except as Specified; No Action except as Specified................................6
      5.5     Satisfaction of Conditions Precedent........................................................6
      5.6     Fixed Investment Trust......................................................................7

SECTION 6.    OWNER TRUSTEE...............................................................................7

      6.1     Acceptance of Trusts and Duties.............................................................7
      6.2     Absence of Certain Duties...................................................................7
      6.3     No Representations or Warranties as to Certain Matters......................................8
      6.4     No Segregation of Monies; Interest..........................................................9
      6.5     Reliance upon Certificates, Counsel and Agents..............................................9
      6.6     Not Acting in Individual Capacity...........................................................9
      6.7     Fees; Compensation.........................................................................10
      6.8     Tax Returns................................................................................10

SECTION 7.    INDEMNIFICATION OF BANK BY OWNER PARTICIPANT...............................................10

SECTION 8.    TRANSFER OF OWNER PARTICIPANT'S INTEREST...................................................12

      8.1     Transfer of Interest.......................................................................12

SECTION 9.    SUCCESSOR OWNER TRUSTEES; CO-TRUSTEES......................................................12

      9.1     Resignation of Owner Trustee; Appointment of Successor.....................................12

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                                TABLE OF CONTENTS
                                     Cont'd
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      9.2     Co-Trustees and Separate Trustees..........................................................13

SECTION 10.   SUPPLEMENTS AND AMENDMENTS TO TRUST AGREEMENT AND OTHER DOCUMENTS..........................15

      10.1    Supplements and Amendments and Delivery Thereof............................................15
      10.2    Discretion as to Execution of Documents....................................................15
      10.3    Absence of Requirements as to Form.........................................................16
      10.4    Distribution of Documents..................................................................16
      10.5    No Request Needed as to Lease Supplement and Trust Indenture Supplement....................16

SECTION 11.           MISCELLANEOUS......................................................................16

      11.1    Termination of Trust Agreement.............................................................16
      11.2    Termination at Option of the Owner Participant.............................................17
      11.3    Owner Participant Has No Legal Title in Trust Estate.......................................17
      11.4    Assignment, Sale, etc. of Aircraft.........................................................17
      11.5    Trust Agreement for Benefit of Certain Parties Only........................................17
      11.6    [Reserved].................................................................................17
      11.7    Notices....................................................................................17
      11.8    Severability...............................................................................18
      11.9    Waivers, Etc...............................................................................18
      11.10   Counterparts...............................................................................18
      11.11   Binding Effect, Etc........................................................................18
      11.12   Headings; References.......................................................................18
      11.13   Governing Law..............................................................................19
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                            TRUST AGREEMENT [_______]

     This TRUST AGREEMENT [______], dated as of [________________], between
[_________], a corporation organized under the laws of the OP Jurisdiction
("Owner Participant"), and Wells Fargo Bank Northwest, National Association, a
national banking association (in its individual capacity, "Bank" and otherwise
not in its individual capacity but solely as trustee hereunder, "Owner
Trustee").

                              W I T N E S S E T H :

SECTION 1. DEFINITIONS

      Capitalized terms used but not defined herein shall have the respective
meanings set forth or incorporated by reference, and shall be construed and
interpreted in the manner described, in Annex A to the Lease.


SECTION 2. DECLARATION OF TRUST

      Bank hereby declares that it will hold the Trust Estate as Owner Trustee
upon the trusts hereinafter set forth for the use and benefit of Owner
Participant, subject, however, to the provisions of and the Lien created by the
Trust Indenture and to the provisions of the Lease and the Participation
Agreement.

SECTION 3. AUTHORIZATION; CONDITIONS PRECEDENT

      3.1   AUTHORIZATION

      In respect of the Aircraft, Owner Participant hereby authorizes and
directs Owner Trustee to, and Owner Trustee agrees for the benefit of Owner
Participant that it will, on and after the Delivery Date, subject (except with
respect to Section 3.1(a)) to due compliance with the terms of Section 3.2:

      (a) execute and deliver the Participation Agreement, the Trust Indenture,
the Lease and the other Owner Trustee Agreements (in the respective forms in
which they are delivered from time to time by Owner Participant to Owner
Trustee);

      (b) subject to the terms of this Trust Agreement, exercise (i) its rights
and perform its duties under the Participation Agreement, (ii) the rights and
perform the duties of Lessor under the Lease and (iii) its rights and perform
its duties under the Trust Indenture and the other Owner Trustee Agreements;

      (c) execute, issue and deliver to Mortgagee for authentication and further
delivery to the Subordination Agent the Equipment Notes in the amount and as
provided in Section 2 of the Participation Agreement;

      (d) purchase the Aircraft pursuant to the Purchase Agreement as assigned
to Owner Trustee pursuant to the Purchase Agreement Assignment;

<PAGE>

      (e) accept from Airframe Manufacturer the delivery of the Aircraft Bill of
Sale, the FAA Bill of Sale and the invoice with respect to such Aircraft and
from Lessee the delivery of the BFE Bill of Sale and the invoice with respect to
such BFE;

      (f) effect the registration of the Aircraft with the FAA in the name of
Owner Trustee by filing or causing to be filed with the FAA: (i) the FAA Bill of
Sale; (ii) an Aircraft Registration Application in the name of Owner Trustee
(including, without limitation, an affidavit from Owner Trustee in compliance
with the provisions of Section 47.7(c)(2) of the FAA Regulations); and (iii)
this Trust Agreement;

      (g) execute and deliver the Financing Statements referred to in Section
5.1.2 (xxii) of the Participation Agreement, together with all other agreements,
documents and instruments referred to in Section 5 of the Participation
Agreement to which Owner Trustee is to be a party;

      (h) make payment of Lessor's Cost for the Aircraft from the aggregate
amount of the Commitments for the Aircraft of Owner Participant and Loan
Participants, to the extent received by Owner Trustee, in the manner provided in
the Participation Agreement;

      (i) execute and deliver Lease Supplement No. 1 covering the Aircraft;

      (j) execute and deliver a Trust Indenture Supplement covering the
Aircraft; and

      (k) execute and deliver all such other instruments, documents or
certificates and take all such other actions in accordance with the direction of
Owner Participant, as Owner Participant may deem necessary or advisable in
connection with the transactions contemplated by this Trust Agreement and the
other Operative Agreements.

      3.2   CONDITIONS PRECEDENT

      The rights and obligations of Owner Trustee to take the actions required
by Section 3.1 shall be subject to the following conditions precedent:

      (a) Owner Trustee shall have received the notice described in Section
5.1.1 of the Participation Agreement, when and as required thereby, or shall
have been deemed to have waived such notice in accordance with Section 5.1.1 of
the Participation Agreement;

      (b) Each Participant shall have made the full amount of its Commitment
specified in Section 2.1 of the Participation Agreement available to Owner
Trustee, in immediately available funds, in accordance with Sections 2 and 4 of
the Participation Agreement; and

      (c) Owner Participant shall have notified Owner Trustee that the terms and
conditions of Section 5 of the Participation Agreement, insofar as they relate
to conditions precedent to performance by Owner Participant of its obligations
thereunder, have been either fulfilled to the satisfaction of, or waived by,
Owner Participant. Owner Participant shall, by instructing Owner Trustee to
release the full amount of its Commitment then held by Owner Trustee as provided
in Section 2 of the Participation Agreement, be deemed to have found
satisfactory to it, or waived, all such conditions precedent.

<PAGE>

SECTION 4. RECEIPT, DISTRIBUTION AND APPLICATION OF INCOME FROM
           THE TRUST ESTATE

      4.1   PAYMENTS FROM TRUST ESTATE ONLY

      Except as provided in Section 6.1, all payments to be made by Owner
Trustee under this Trust Agreement shall be made only from (a) in the case of
funds made available in accordance with Section 4 of the Participation
Agreement, the Commitments (except as otherwise provided in Section 14 of the
Participation Agreement) and (b) in the case of all other payments, the income
from and proceeds of the Trust Estate to the extent that Owner Trustee shall
have received sufficient income or proceeds from the Trust Estate to make such
payments. Owner Participant agrees that it will look solely (y) in the case of
funds made available in accordance with Section 4 of the Participation
Agreement, to the Commitments and any income therefrom (except as otherwise
provided in Section 14 of the Participation Agreement) and (z) in the case of
all other payments, to the income from and proceeds of the Trust Estate to the
extent available for distribution to Owner Participant as provided in this Trust
Agreement. Except as provided in Section 6.1, Owner Participant agrees that Bank
is neither personally liable to Owner Participant for any amounts payable nor
subject to any other liability under this Trust Agreement.

      4.2   DISTRIBUTION OF PAYMENTS

               4.2.1    PAYMENTS TO MORTGAGEE

      Until the Trust Indenture shall have been discharged pursuant to Section
10.01 thereof, all Rent, insurance proceeds and requisition or other payments of
any kind included in the Trust Estate (other than Excluded Payments) payable to
Owner Trustee shall be payable directly to Mortgagee (and, if any of the same
are received by Owner Trustee, shall upon receipt be paid over to Mortgagee
without deduction, set-off or adjustment of any kind) for distribution in
accordance with the provisions of Article III of the Trust Indenture; PROVIDED,
that any payments received by Owner Trustee from (a) Lessee with respect to
Owner Trustee's fees and disbursements or (b) Owner Participant pursuant to
Section 7 shall not be paid over to Mortgagee but shall be retained by Owner
Trustee and applied toward the purpose for which such payments were made.

               4.2.2    PAYMENTS TO OWNER TRUSTEE, OTHER PARTIES

      After the Trust Indenture shall have been discharged pursuant to Section
10.01 thereof, any payment of the type referred to in Section 4.2.1 (other than
Excluded Payments) received by Owner Trustee, any payment received from
Mortgagee (other than Excluded Payments) and any other amount received as part
of the Trust Estate and for the application or distribution of which no
provision is made in this Trust Agreement shall be distributed forthwith upon
receipt by Owner Trustee in the following order of priority: FIRST, so much of
such payment as shall be required to reimburse Owner Trustee for any expenses
not otherwise reimbursed as to which Owner Trustee is entitled to be so
reimbursed pursuant to the provisions hereof shall be retained by Owner Trustee;
SECOND, so much of the remainder for which provision as to the application
thereof is contained in the Lease or any of the other Operative Agreements shall
be applied and distributed in accordance with the terms of the Lease or such

<PAGE>

other Operative Agreement; and THIRD, the balance, if any, shall be paid to
Owner Participant.

               4.2.3    CERTAIN DISTRIBUTIONS TO OWNER PARTICIPANT

      All amounts from time to time distributable by Mortgagee to Owner
Participant pursuant to the Trust Indenture shall, if paid to Owner Trustee, be
distributed by Owner Trustee to Owner Participant in accordance with the
provisions of Article III of the Trust Indenture; PROVIDED, that any payments
received by Owner Trustee from (a) Lessee with respect to Owner Trustee's fees
and disbursements or (b) Owner Participant pursuant to Section 7 shall not be
paid over to Owner Participant but shall be retained by Owner Trustee and
applied toward the purpose for which such payments were made.

               4.2.4    EXCLUDED PAYMENTS

      Any Excluded Payments received by Owner Trustee shall be paid by Owner
Trustee to the Person to whom such Excluded Payments are payable under the
provisions of the Participation Agreement, the Tax Indemnity Agreement or the
Lease.

               4.2.5    MULTIPLE OWNER PARTICIPANTS

      If, as a result of a transfer by Owner Participant under Section 8.1,
there is more than one Owner Participant under this Trust Agreement, each such
Owner Participant shall hold in proportion to its respective beneficial interest
in the Trust Estate an undivided beneficial interest in the entire Trust Estate
and is entitled to receive ratably with any other Owner Participant payments
distributable by Owner Trustee under this Trust Agreement. No Owner Participant
shall have legal title to the Aircraft or any other portion of the Trust Estate.

      4.3   METHOD OF PAYMENTS

      Owner Trustee shall make distributions or cause distributions to be made
to Owner Participant pursuant to this Section 4 by transferring the amount to be
distributed by wire transfer in immediately available funds on the day received
(or on the next succeeding Business Day if the funds to be so distributed shall
not have been received by Owner Trustee by 12:00 noon, New York City time, and
which funds Owner Trustee shall not have been reasonably able to distribute to
Owner Participant on the day received) to Owner Participant's account set forth
in Schedule 1 to the Participation Agreement or to such other account or
accounts of Owner Participant as Owner Participant may designate from time to
time in writing to Owner Trustee; PROVIDED, that Owner Trustee shall use
reasonable efforts to invest overnight, in investments that would be permitted
under Section 4.4 of the Lease, all funds received by it at or later than 12:00
noon, New York City time, and which funds Owner Trustee shall not have been
reasonably able to distribute to Owner Participant on the day received).

<PAGE>

SECTION 5. DUTIES OF OWNER TRUSTEE

      5.1   NOTICE OF EVENT OF DEFAULT

      (a) If Owner Trustee shall have knowledge of a Lease Default or a Lease
Event of Default or an Indenture Default or an Indenture Event of Default, Owner
Trustee shall give to Owner Participant, Mortgagee and Lessee prompt telephonic
or telex notice thereof followed by prompt confirmation thereof by certified
mail, postage prepaid, PROVIDED, that (i) in the case of an event which with the
passage of time would constitute an Indenture Event of Default of the type
referred to in paragraph (c) or (e) of Section 4.02 of the Trust Indenture, such
notice shall in no event be furnished later than ten days after Owner Trustee
shall first have knowledge of such event and (ii) in the case of a
misrepresentation by Owner Trustee which with the passage of time would
constitute an Indenture Event of Default of the type referred to in paragraph
(d) of Section 4.02 of the Trust Indenture, such notice shall in no event be
furnished later than ten days after Owner Trustee shall first have knowledge of
such event.

      (b) Subject to the terms of Section 5.3, Owner Trustee shall take such
action or shall refrain from taking such action, not inconsistent with the
provisions of the Trust Indenture, with respect to such Lease Default, Lease
Event of Default, Indenture Default or Indenture Event of Default or other event
as Owner Trustee shall be directed in writing by Owner Participant. For all
purposes of this Trust Agreement, the Lease and the other Operative Agreements,
in the absence of Actual Knowledge of Owner Trustee, Owner Trustee shall not be
deemed to have knowledge of a Lease Default, Lease Event of Default, Indenture
Default or Indenture Event of Default unless notified in writing by Mortgagee,
Owner Participant or Lessee.

      5.2   ACTION UPON INSTRUCTIONS

      Subject to the terms of Sections 5.1 and 5.3, upon the written
instructions at any time and from time to time of Owner Participant, Owner
Trustee will take such of the following actions, not inconsistent with the
provisions of the Lease and the Trust Indenture, as may be specified in such
instructions: (a) give such notice or direction or exercise such right, remedy
or power under this Trust Agreement or any of the other Owner Trustee Agreements
or in respect of all or any part of the Trust Estate, or take such other action,
as shall be specified in such instructions (including entering into such
agreements and instruments as shall be necessary under Section 10); (b) take
such action to preserve or protect the Trust Estate (including the discharge of
Liens) as may be specified in such instructions; (c) approve as satisfactory to
it all matters required by the terms of the Lease or the other Operative
Agreements to be satisfactory to Owner Trustee, it being understood that without
written instructions of Owner Participant, Owner Trustee shall not approve any
such matter as satisfactory to it; (d) subject to the rights of Lessee under the
Operative Agreements, after the expiration or earlier termination of the Lease,
convey all of 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 other action with respect to, the Aircraft on such
terms as shall be designated in such instructions; and (e) take or refrain from
taking such other action or actions as may be specified in such instructions.

<PAGE>

      5.3   LIMITATIONS ON DUTIES

      Owner Trustee shall not be required to take any action under Section 5.1
(other than the giving of the notices referred to therein) or 5.2 if Owner
Trustee shall reasonably believe such action is not adequately indemnified by
Owner Participant under Section 7, unless Lessee or Owner Participant agrees to
furnish such additional indemnity as shall reasonably be required, in manner and
form satisfactory to Owner Trustee, and, in addition to the extent not otherwise
paid pursuant to the provisions of the Lease or of the Participation Agreement,
to pay the reasonable compensation of Owner Trustee for the services performed
or to be performed by it pursuant to such direction and any reasonable fees and
disbursements of counsel or agents employed by Owner Trustee in connection
therewith. Owner Trustee shall not be required to take any action under Section
5.1 or 5.2 (other than the giving of the notices referred to therein) if Owner
Trustee shall have been advised by counsel that such action is contrary to the
terms of any of the Owner Trustee Agreements or is otherwise contrary to Law and
Owner Trustee has delivered to Owner Participant written notice of the basis for
its refusal to act.

      5.4   NO DUTIES EXCEPT AS SPECIFIED; NO ACTION EXCEPT AS SPECIFIED

               5.4.1    NO DUTIES EXCEPT AS SPECIFIED

      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 to otherwise take or refrain from taking any action under,
or in connection with, any of the Owner Trustee Agreements, except as expressly
required by the terms of any of the Owner Trustee Agreements, or (to the extent
not inconsistent with the provisions of the Trust Indenture) as expressly
provided by the terms hereof or in a written instruction from Owner Participant
received pursuant to the terms of Section 5.1 or 5.2, and no implied duties or
obligations shall be read into this Trust Agreement against Owner Trustee. Bank
agrees that it will, in its individual capacity and at its own cost or expense
(but without any right of indemnity in respect of any such cost or expense
hereunder or under the Participation Agreement), promptly take such action as
may be necessary to duly discharge and satisfy in full all Lessor Liens
attributable to it in its individual capacity which it is required to discharge
pursuant to Section 7.3.1 of the Participation Agreement and otherwise comply
with the terms of said Section binding upon it.

               5.4.2    NO ACTION EXCEPT AS SPECIFIED

      Owner Trustee shall have no power, right or authority to, and 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 (a) as expressly required
by the terms of any of the Owner Trustee Agreements, (b) as expressly provided
by the terms hereof or (c) as expressly provided in written instructions from
Owner Participant pursuant to Section 5.1 or 5.2.

      5.5   SATISFACTION OF CONDITIONS PRECEDENT

      Anything in this Trust Agreement to the contrary notwithstanding, Owner
Trustee shall, subject to the satisfaction of special counsel for Owner Trustee
of the occurrence of all the applicable conditions precedent specified in
Section 3.2, comply with the provisions of Section 3.1.

<PAGE>

5.6      FIXED INVESTMENT TRUST

      Notwithstanding anything in this Trust Agreement to the contrary, Owner
Trustee shall not be authorized and shall have no power to "vary the investment"
of Owner Participant within the meaning of Treasury Regulations Section
301.7701-4(c)(1), it being understood that Owner Trustee shall have the power
and authority to fulfill its obligations under Section 4.3 hereof and Section
4.4 of the Lease.

SECTION 6. OWNER TRUSTEE

      6.1   ACCEPTANCE OF TRUSTS AND DUTIES

      Bank accepts the trusts hereby created and agrees to perform the same as
Owner Trustee but only upon the terms hereof and the Trust Indenture applicable
to it. Owner Trustee also agrees to receive and disburse all monies received by
it constituting part of the Trust Estate pursuant to the terms hereof. Bank
shall not be answerable or accountable under any circumstances, except for (a)
its own willful misconduct or gross negligence (including, without limitation,
in connection with any activities of Owner Trustee in violation of Section
5.4.2), (b) its failure (in its individual capacity) to perform its obligations
under Section 5.4.1, (c) its or Owner Trustee's failure to use ordinary care to
receive or disburse funds or to comply with the first sentence of Section 6.8,
(d) liabilities that may result from the inaccuracy of any representation or
breach of warranty of it in its individual capacity (or from the failure by it
in its individual capacity to perform any covenant) in this Trust Agreement, the
Trust Indenture, the Lease or the Participation Agreement or elsewhere in any of
the other Operative Agreements, (e) taxes, fees or other charges on, based on or
measured by any fees, commissions or compensation received by Bank in connection
with the transactions contemplated by this Trust Agreement and the other
Operative Agreements to which it (in its individual capacity or as Owner
Trustee) is a party, (f) its or Owner Trustee's failure to use ordinary care in
receiving or disbursing funds or in connection with its obligation to invest
funds pursuant to Section 4.4 of the Lease or Section 4.3 hereof, (g) for 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 5.1
(other than the first sentence thereof), 6.8 or 9.2 hereof or Section 4.01 of
the Trust Indenture. Bank shall have no obligation to advance its individual
funds for any purpose, and Owner Trustee shall have no obligation to distribute
to Owner Participant, Lessee or any third party any amounts to be paid to Owner
Trustee until such amounts are collected by Owner Trustee.

      6.2   ABSENCE OF CERTAIN DUTIES

      (a) Except in accordance with written instructions furnished pursuant to
Section 5.1 or 5.2 and except as provided in, and without limiting the
generality of, Sections 3.1 and 5.4.1 and the last sentence of Section 9.1.2,
and subject to Section 4.01 of the Trust Indenture, neither Owner Trustee nor
Bank shall have any duty (i) to see to any recording or filing of any Operative
Agreement or of any supplement to any thereof or to see to the maintenance of
any such recording or filing or any other filing of reports with the FAA or
other governmental agencies, except that of Bank to comply with the FAA
reporting requirements set forth in 14 C.F.R. ss. 47.45 and 14 C.F.R. ss. 47.51,
and Owner Trustee shall, to the extent that information for that purpose is

<PAGE>

timely supplied by Lessee pursuant to any of the Operative Agreements, complete
and timely submit (and furnish Owner Participant with a copy of) any and all
reports relating to the Aircraft that 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, other than to
forward to Owner Participant copies of all reports and other written information
which Owner Trustee receives from Lessee pursuant to Section 11 of the Lease,
(iii) except as provided in Section 7.3.1 or 7.3.2 of the Participation
Agreement, Section 4.01 of the Trust Indenture or Section 5.4 or 6.1 hereof, 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 or assessed
or levied against any part of the Trust Indenture Estate or the Trust Estate,
except as provided in Section 6.3.9 of the Participation Agreement or (iv) to
inspect Lessee's books and records with respect to the Aircraft at any time
permitted pursuant to the Lease.

      (b) Notwithstanding clause (a), Owner Trustee will furnish to Mortgagee
and 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.

      6.3   NO REPRESENTATIONS OR WARRANTIES AS TO CERTAIN MATTERS

      NEITHER BANK NOR OWNER TRUSTEE MAKES OR SHALL BE DEEMED TO HAVE MADE (a)
ANY REPRESENTATION OR WARRANTY, EXPRESS OR IMPLIED, AS TO THE TITLE,
AIRWORTHINESS, VALUE, CONDITION, DESIGN, OPERATION, MERCHANTABILITY OR FITNESS
FOR USE FOR A PARTICULAR PURPOSE OF THE AIRCRAFT OR ANY PART THEREOF, AS TO THE
ABSENCE OF LATENT OR OTHER DEFECTS, WHETHER OR NOT DISCOVERABLE, AS TO THE
ABSENCE OF ANY INFRINGEMENT OF ANY PATENT, TRADEMARK OR COPYRIGHT, THE ABSENCE
OF ANY STRICT LIABILITY OBLIGATION OR ANY OTHER REPRESENTATION OR WARRANTY,
EXPRESS OR IMPLIED, WITH RESPECT TO THE AIRCRAFT OR ANY PART THEREOF WHATSOEVER,
except that Bank warrants to Owner Participant that on the Delivery Date Owner
Trustee shall have received whatever title to the Aircraft that was conveyed to
it and that the Aircraft shall, on the Delivery Date and during the Term, be
free of Lessor Liens attributable to Bank or (b) any representation or warranty
as to the validity, legality or enforceability of this Trust Agreement or any
other Operative Agreement to which Bank, 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 by such party as a
representation by Bank, in its individual capacity or as Owner Trustee, as the
case may be, and except that Bank 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 due
authorization, execution and delivery by Owner Participant of this Trust
Agreement) the other Operative Agreements to which it or Owner Trustee is a
party have been (or at the time of execution and delivery of any such instrument

<PAGE>

by it or Owner Trustee under this Trust Agreement 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 itself or Owner
Trustee, as the case may be, and that this Trust Agreement constitutes the
legal, valid and binding obligation of Bank or Owner Trustee, as the case may
be, enforceable against Bank or Owner Trustee, as the case may be, in accordance
with its terms.

      6.4   NO SEGREGATION OF MONIES; INTEREST

      Monies received by Owner Trustee under this Trust Agreement need not be
segregated in any manner except to the extent required by Law, or except as
provided in written instructions from Owner Participant, and shall be invested
as provided in Section 4.3 hereof or Section 4.4 of the Lease.

      6.5   RELIANCE UPON CERTIFICATES, COUNSEL AND AGENTS

      Owner Trustee shall incur no liability to anyone in acting in good faith
in reliance upon and in accordance with 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 in this Trust Agreement,
any request, direction, order or demand of Owner Participant or Lessee mentioned
in this Trust Agreement or in any of the other Owner Trustee Agreements shall be
sufficiently evidenced by written instruments signed by the Chairman of the
Board, the President, any Vice President or any other officer and in the name of
Owner Participant or Lessee, as the case may be. Owner Trustee may accept a copy
of a resolution of the Board of Directors or Executive Committee of Lessee,
certified by the Secretary or an Assistant Secretary of Lessee as duly adopted
and in full force and effect, as conclusive evidence that such resolution has
been duly adopted by said Board of Directors or Executive Committee 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 in this Trust Agreement,
Owner Trustee may, absent Actual Knowledge to the contrary, for all purposes
rely on a certificate signed by the Chairman of the Board, the President, any
Vice President or any other officer of Lessee, and the Treasurer or an Assistant
Treasurer or the Secretary or an Assistant Secretary of Lessee, as to such fact
or matter, and such certificate shall constitute full protection to Owner
Trustee for any action taken or omitted to be taken by it in good faith in
reliance thereon and in accordance therewith. In the administration of trusts
under this Trust Agreement, Owner Trustee may execute any of the trusts or
powers and perform its powers and duties under this Trust Agreement directly or
through agents or attorneys and may, at the expense of the Trust Estate, consult
with counsel, accountants and other skilled persons to be selected and employed
by it. 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.

      6.6   NOT ACTING IN INDIVIDUAL CAPACITY

      In acting under this Trust Agreement, Bank acts solely as Owner Trustee
and not in its individual capacity except as otherwise expressly provided in

<PAGE>

this Trust Agreement or in the other Operative Agreements to which it is a
party; and, except as may be otherwise expressly provided in this Trust
Agreement, the Lease, the Participation Agreement and the Trust Indenture, all
persons, other than the Owner Participant as provided in this Trust Agreement or
the Trust Indenture, having any claim against Owner Trustee by reason of the
transactions contemplated hereby shall look only to the Trust Estate for payment
or satisfaction thereof except to the extent provided in Section 6.1 or
otherwise as Owner Trustee shall expressly agree otherwise in writing.

      6.7   FEES; COMPENSATION

      Lessee or Owner Participant shall pay the Transaction Expenses of Owner
Trustee pursuant to Section 9.2 of the Participation Agreement. The Trust Estate
shall not have any liability for any such fees and expenses; PROVIDED, that the
foregoing shall not limit the obligations of Owner Participant under Sections
5.3 and 7; PROVIDED, that Owner Trustee shall have a Lien upon the Trust Estate
for any such fee not paid by Lessee or Owner Participant, as the case may be, as
contemplated by Section 9.2 of the Participation Agreement and such Lien shall
entitle Owner Trustee to priority as to payment thereof over payment to any
other Person under this Trust Agreement; PROVIDED, that such Lien shall be
subject and subordinate in all events to the Lien of the Trust Indenture; and
PROVIDED, FURTHER, that Owner Trustee shall have no right to exercise, and shall
not exercise, any rights or remedies Owner Trustee may have with respect to such
Lien unless and until the Secured Obligations have been paid and performed in
full.

      6.8   TAX RETURNS

      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. Owner Participant
shall be responsible for causing to be prepared and filed all income tax returns
required to be filed by Owner Participant. Owner Trustee shall be responsible
for causing to be prepared, at the request of Owner Participant and at the
expense of Lessee, all income tax returns required to be filed with respect to
the trust created hereby and shall execute and file such returns; PROVIDED, that
Owner Trustee shall send promptly a completed copy of such return to Owner
Participant not more than sixty nor less than fifteen days prior to the due date
of the return, PROVIDED, that Owner Trustee shall have timely received all
necessary information to complete and deliver to Owner Participant such return.
Owner Participant, upon request, will furnish Owner Trustee with all such
information as may be reasonably required from Owner Participant in connection
with the preparation of such income tax returns. Owner Trustee shall keep copies
of all returns delivered to or filed by it.

SECTION 7. INDEMNIFICATION OF BANK BY OWNER PARTICIPANT

      Owner Participant hereby agrees, whether or not any of the transactions
contemplated hereby shall be consummated, to assume liability for, and hereby
indemnifies, protects, saves and keeps harmless, Bank and its successors,
assigns, agents and servants, from and against any and all liabilities,
obligations, losses, damages, penalties, taxes (excluding any Taxes which are
not required to be indemnified by Lessee pursuant to Section 9.1 or 9.3 of the
Participation Agreement and excluding any taxes payable by Bank on or measured

<PAGE>

by any compensation received by Bank for its services under this Trust
Agreement), claims, actions, suits, costs, expenses or disbursements (including,
without limitation, reasonable legal fees and expenses, but excluding internal
costs and expenses such as salaries and overhead, and including, without
limitation, any liability of an owner, any strict liability and any liability
without fault) of any kind and nature whatsoever which may be imposed on,
incurred by or asserted against Bank (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 Aircraft
(including, without limitation, latent and other defects, 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 Owner Trustee, under this Trust Agreement, except
(a) in the case of gross negligence or willful misconduct on the part of Bank,
in its individual capacity or as Owner Trustee, in the performance or
nonperformance of its duties under this Trust Agreement or under any of the
other Owner Trustee Agreements or (b) those Claims resulting from the inaccuracy
of any representation or warranty of Bank (or from the failure of Bank to
perform any of its covenants) in Section 6.3, in Section 6.03 of the Trust
Indenture, in Section 4 of the Lease, in Section 6.3 of the Participation
Agreement or elsewhere in any of the Operative Agreements or (c) as may result
from a breach by Bank of its covenant in the last sentence of Section 5.4.1 or
(d) in the case of the failure to use ordinary care on the part of Bank, in its
individual capacity or as Owner Trustee, in the receipt or disbursement of funds
or in connection with its obligation to invest funds pursuant to Section 4.4 of
the Lease or Section 4.3 hereof or in compliance with the provisions of the
first sentence of Section 6.8 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 5.1, 6.8 or 9.2 hereof or Section 4.01 of the
Trust Indenture, or (f) those claims arising under any circumstances or upon any
terms where Lessee would not have been required to indemnify Bank pursuant to
Section 9.1 or 9.3 of the Participation Agreement (disregarding for purposes of
this paragraph Sections 9.1.2(b) and 9.3.2(j)); PROVIDED, that before asserting
its right to indemnification, if any, pursuant to this Section 7, Bank shall
first demand its corresponding right to indemnification pursuant to Section 9 of
the Participation Agreement (but need not exhaust any or all remedies available
thereunder). The indemnities contained in this Section 7 extend to Bank only in
its individual capacity and shall not be construed as indemnities of the Trust
Indenture Estate or the Trust Estate (except to the extent, if any, that Bank
has been reimbursed by the Trust Indenture Estate or the Trust Estate for
amounts covered by the indemnities contained in this Section 7). The indemnities
contained in this Section 7 shall survive the termination of this Trust
Agreement. In addition, if necessary, Bank shall be entitled to indemnification
from the Trust Estate, subject to the Lien of the Trust Indenture, for any
liability, obligation, loss, damage, penalty, tax, claim, action, suit, cost,
expense or disbursement indemnified against pursuant to this Section 7 to the
extent not reimbursed by Lessee, Owner Participant or others, but without
releasing any of them from their respective agreements of reimbursement; and, to
secure the same Bank shall have a lien on the Trust Estate, subject to the lien
of the Trust Indenture and subject further to the provisions of Section 6.7,
which shall be prior to any interest therein of Owner Participant. The payor of

<PAGE>

any indemnity under this Section 7 shall be subrogated to any right of the
person indemnified in respect of the matter as to which such indemnity was paid.

SECTION 8. TRANSFER OF OWNER PARTICIPANT'S INTEREST

      8.1   TRANSFER OF INTEREST

      All provisions of Section 10 of the Participation Agreement shall (with
the same force and effect as if set forth in full in this Section 8.1) be
applicable to any assignment, conveyance or other transfer by Owner Participant
of any of its right, title or interest in and to the Participation Agreement,
the Trust Estate or this Trust Agreement.

SECTION 9. SUCCESSOR OWNER TRUSTEES; CO-TRUSTEES

      9.1   RESIGNATION OF OWNER TRUSTEE; APPOINTMENT OF SUCCESSOR

               9.1.1    RESIGNATION OR REMOVAL

      Owner Trustee or any successor Owner Trustee (a) shall resign if required
to do so pursuant to Section 13.3 of the Participation Agreement or upon
obtaining Actual Knowledge of any facts that would cast doubt upon its
continuing status as a Citizen of the United States and (b) may resign at any
time without cause by giving at least 60 days' prior written notice to Owner
Participant, Mortgagee and Lessee, such resignation to be effective upon the
assumption of the trusts hereunder by the successor Owner Trustee under Section
9.1.2. In addition, Owner Participant may at any time remove Owner Trustee, with
or without cause by a notice in writing delivered to Owner Trustee, Mortgagee
and Lessee, such removal to be effective upon the assumption of the trusts
hereunder by the successor Owner Trustee under Section 9.1.2, PROVIDED, that, in
the case of a removal without cause, unless a Lease Event of Default shall have
occurred and be continuing, such removal shall be subject to the consent of
Lessee (which consent shall not be unreasonably withheld). In the case of the
resignation or removal of Owner Trustee, Owner Participant may appoint a
successor Owner Trustee by an instrument signed by Owner Participant, with,
unless a Lease Event of Default shall have occurred and be continuing, the
consent of Lessee (which consent shall not be unreasonably withheld). If a
successor Owner Trustee shall not have been appointed within 30 days after such
notice of resignation or removal, Owner Trustee, any Owner Participant, Lessee
or Mortgagee 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.

               9.1.2    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, Lessee and
Mortgagee, an instrument accepting such appointment and assuming the obligations
of Owner Trustee, in its individual capacity and as Owner Trustee, under the
Owner Trustee Agreements, and thereupon such successor Owner Trustee, without
further act, shall become vested with all the estates, properties, rights,

<PAGE>

powers, duties and trusts of the predecessor Owner Trustee in the trusts under
this Trust Agreement with like effect as if originally named Owner Trustee in
this Trust Agreement; 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
under this Section 9.1, the predecessor Owner Trustee will execute such
documents as are provided to it by such successor Owner Trustee and will take
such further actions as are requested of it by such successor Owner Trustee as
are required 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.

               9.1.3    QUALIFICATIONS

      Any successor Owner Trustee, however appointed, shall be a Citizen of the
United States and shall also be a bank or trust company organized under the Laws
of the United States 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 Owner Trustee under this Trust
Agreement upon reasonable or customary terms. No such successor Owner Trustee
shall be located in a jurisdiction which creates material adverse consequences
for Lessee (unless such material adverse consequences would be created by
substantially all jurisdictions where major banking or trust institutions are
located).

               9.1.4    MERGER, ETC.

      Any corporation into which Bank may be merged or converted or with which
it may be consolidated, or any corporation resulting from any merger, conversion
or consolidation to which Bank shall be a party, or any corporation to which
substantially all the corporate trust business of Bank may be transferred,
shall, subject to the terms of Section 9.1.3, be Owner Trustee under this Trust
Agreement without further act, PROVIDED, that such corporation shall not also be
the Mortgagee.

      9.2   CO-TRUSTEES AND SEPARATE TRUSTEES

      (a) If at any time it shall be necessary or prudent in order to conform to
any Law of any jurisdiction in which all or any part of the Trust Estate is
located, or Owner Trustee being advised by counsel shall determine that it is so
necessary or prudent in the interest of Owner Participant or Owner Trustee, or
Owner Trustee shall have been directed to do so by Owner Participant, Owner
Trustee and 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 or all
of which shall be a Citizen of the United States) approved by Owner Trustee and
Owner Participant, either to act as co-trustee, jointly with Owner Trustee, or
to act as separate trustee under this Trust Agreement (any such co-trustee or
separate trustee being herein sometimes referred to as an "additional trustee").

<PAGE>

In the event 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 Owner Trustee so to do, or in case a Lease Event of Default or
Indenture Event of Default shall occur and be continuing, Owner Trustee may act
under the foregoing provisions of this Section 9.2 without the concurrence of
Owner Participant; and Owner Participant hereby appoints Owner Trustee its agent
and attorney-in-fact to act for it under the foregoing provisions of this
Section 9.2 in either of such contingencies.

      (b) Every additional trustee under this Trust Agreement shall, to the
extent permitted by Law, be appointed and act, and Owner Trustee and its
successors shall act, subject to the following provisions and conditions:

            (i) All powers, duties, obligations and rights conferred upon Owner
      Trustee in respect of the custody, control and management of monies, the
      Aircraft or documents authorized to be delivered under this Trust
      Agreement or under the Participation Agreement shall be exercised solely
      by Owner Trustee;

            (ii) All other rights, powers, duties and obligations conferred or
      imposed upon Owner Trustee shall be conferred or imposed upon and
      exercised or performed by Owner Trustee and such additional trustee
      jointly, except to the extent that under any Law of any jurisdiction in
      which any particular act or acts are to be performed (including the
      holding of title to the Trust Estate) 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;

            (iii) No power given to, or which it is provided hereby may be
      exercised by, any such additional trustee shall be exercised under this
      Trust Agreement by such additional trustee, except jointly with, or with
      the consent in writing of, Owner Trustee;

            (iv) No trustee under this Trust Agreement shall be personally
      liable by reason of any action or omission of any other trustee under this
      Trust Agreement;

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

            (vi) No appointment of, or action by, any additional trustee will
      relieve Owner Trustee of any of its obligations under, or otherwise affect
      any of the terms of, the Trust Indenture or affect the interests of
      Mortgagee or the Certificate Holders in the Trust Indenture Estate.

      (c) In case any separate trustee under this Section 9.2 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 Law,

<PAGE>

vest in and be exercised by Owner Trustee, without the appointment of a
successor to such separate trustee.

SECTION 10. SUPPLEMENTS AND AMENDMENTS TO TRUST AGREEMENT
            AND OTHER DOCUMENTS

      10.1  SUPPLEMENTS AND AMENDMENTS AND DELIVERY THEREOF

               10.1.1   SUPPLEMENTS AND AMENDMENTS

      Subject to Section 7.2.2 of the Participation Agreement, this Trust
Agreement may not be amended, supplemented or otherwise modified except by an
instrument in writing signed by Owner Trustee and Owner Participant. Subject to
Section 10.2, Section 9.01 of the Trust Indenture and Section 7.6.7 of the
Participation Agreement, Owner Trustee will execute any amendment, supplement or
other modification of this Trust Agreement or of any other Owner Trustee
Agreement which it is requested in writing to execute by Owner Participant,
except that Owner Trustee shall not execute any such amendment, supplement or
other modification which, by the express provisions of any of the above
documents, requires the consent of any other party unless such consent shall
have been obtained; and PROVIDED, that, without the prior written consent of
Owner Participant, (a) no such supplement, amendment or modification shall (i)
modify any of the provisions of Section 4 or this Section 10.1, (ii) reduce,
modify or amend any indemnities in favor of Owner Participant as set forth in
Section 9 of the Participation Agreement or in the Tax Indemnity Agreement,
(iii) reduce the amount or extend the time of payment of Basic Rent,
Supplemental Rent, Stipulated Loss Value or Termination Value as set forth in
the Lease (except in accordance with Section 3 of the Lease) or (iv) modify any
of the rights of Owner Participant under the Trust Indenture and (b) no such
supplement, amendment or modification shall require Owner Participant to invest
or advance funds or shall entail any additional personal liability or the
surrender of any indemnification, claim or individual right on the part of Owner
Participant with respect to any agreement or obligation.

               10.1.2   DELIVERY OF AMENDMENTS AND SUPPLEMENTS TO CERTAIN
                        PARTIES

      A signed copy of each amendment or supplement referred to in Section
10.1.1 to which Lessee is not a party shall be delivered promptly by Owner
Trustee to Lessee, and a signed copy of each amendment or supplement referred to
in Section 10.1.1 shall be delivered promptly by Owner Trustee to Mortgagee.

      10.2  DISCRETION AS TO EXECUTION OF DOCUMENTS

      Prior to executing any document required to be executed by it pursuant to
the terms of Section 10.1, Owner Trustee shall be entitled to receive an opinion
of its counsel to the effect that the execution of such document is authorized
under this Trust Agreement. If in the opinion of Owner Trustee any such document
adversely affects any right, duty, immunity or indemnity in favor of Owner
Trustee under this Trust Agreement or under any other Owner Trustee Agreement,
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

<PAGE>

the Trust Estate and the Owner Trustee against any and all liabilities, costs
and expenses arising out of the execution of such documents.

      10.3  ABSENCE OF REQUIREMENTS AS TO FORM

      It shall not be necessary for any written request furnished pursuant to
Section 10.1 to specify the particular form of the proposed documents to be
executed pursuant to such Section 10.1, but it shall be sufficient if such
request shall indicate the substance thereof.

      10.4  DISTRIBUTION OF DOCUMENTS

      Promptly after the execution by Owner Trustee of any document entered into
pursuant to Section 10.1, Owner Trustee shall mail, by certified mail, postage
prepaid, a conformed copy thereof to Owner Participant, but the failure of Owner
Trustee to mail such conformed copy shall not impair or affect the validity of
such document.

      10.5  NO REQUEST NEEDED AS TO LEASE SUPPLEMENT AND TRUST INDENTURE
            SUPPLEMENT

      No written request pursuant to Section 10.1 shall be required to enable
Owner Trustee to enter into, pursuant to Section 3.1 and the Lease or the Trust
Indenture, as the case may be, the Lease Supplement with Lessee and the Trust
Indenture Supplement.

SECTION 11. MISCELLANEOUS

      11.1  TERMINATION OF TRUST AGREEMENT

      This Trust Agreement and the trusts created hereby shall be of no further
force or effect upon the earlier of (a) both the final discharge of the Trust
Indenture pursuant to Section 10.01 thereof and the sale or other final
disposition by Owner Trustee of all property constituting part of the Trust
Estate and the final distribution by Owner Trustee of all monies or other
property or proceeds constituting part of the Trust Estate in accordance with
Section 4, PROVIDED, that at such time Lessee shall have fully complied with all
of the terms of the Lease and the Participation Agreement or (b) 21 years less
one day after the death of the last survivor of all of the descendants of the
grandparents of David C. Rockefeller living on the date of the earliest
execution of this Trust Agreement by any party hereto, but if this Trust
Agreement and the trusts created hereby shall be or become authorized under
applicable Law to be valid for a period commencing on the 21st anniversary of
the death of such last survivor (or, without limiting the generality of the
foregoing, if legislation shall become effective providing for the validity of
this Trust Agreement and the trusts created hereby for a period in gross
exceeding the period for which this Trust Agreement and the trusts created
hereby are hereinabove stated to extend and be valid), then this Trust Agreement
and the trusts created hereby shall not terminate under this clause (b) but
shall extend to and continue in effect, but only if such nontermination and
extension shall then be valid under applicable Law, until the day preceding such
date as the same shall, under applicable Law, cease to be valid; otherwise this
Trust Agreement and the trusts created hereby shall continue in full force and
effect in accordance with the terms hereof. Except as expressly set forth in
Section 11.2, this Trust Agreement and the trusts created hereby may not be
revoked by Owner Participant.

<PAGE>

      11.2  TERMINATION AT OPTION OF THE OWNER PARTICIPANT

      Notwithstanding Section 11.1 hereof, this Agreement and trust created
hereby shall terminate and the Trust Estate shall be distributed to the Owner
Participant, and this 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 time the Lien of the Trust Indenture is discharged under Section 10.01 of
the Trust Indenture and after the Lease shall no longer be in effect.

      11.3  OWNER PARTICIPANT HAS NO LEGAL TITLE IN TRUST ESTATE

      No Owner Participant shall 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 Owner Participant in and to the Trust Estate under this Trust
Agreement shall operate to terminate this Trust Agreement or the trusts under
this Trust Agreement or entitle any successors or transferees of Owner
Participant to an accounting or to the transfer of legal title to any part of
the Trust Estate.

      11.4  ASSIGNMENT, SALE, ETC. OF AIRCRAFT

      Any assignment, sale, transfer or other conveyance of the Aircraft by
Owner Trustee made pursuant to the terms of this Trust Agreement or of the Lease
or the Participation Agreement shall bind Owner Participant and shall be
effective to transfer or convey all right, title and interest of Owner Trustee
and Owner Participant in and to the Aircraft. 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 Owner Trustee.

      11.5  TRUST AGREEMENT FOR BENEFIT OF CERTAIN PARTIES ONLY

      Except for the terms of Section 10 of the Participation Agreement
incorporated in Section 8 and except as otherwise provided in Sections 5.1, 6.7,
9, 10.1 and 11.1, nothing in this Trust Agreement, whether express or implied,
shall be construed to give any person other than Owner Trustee and Owner
Participant any legal or equitable right, remedy or claim under or in respect of
this Trust Agreement; and this Trust Agreement shall be held to be for the sole
and exclusive benefit of Owner Trustee and Owner Participant.

      11.6  [RESERVED]

      11.7  NOTICES

      Unless otherwise expressly permitted by the terms of this Trust Agreement,
all notices, requests, demands, authorizations, directions, consents, waivers
and other communications required or permitted to be made, given, furnished or
filed under this Trust Agreement shall be in writing, shall refer specifically
to this Trust Agreement and shall be personally delivered, sent by telecopy,

<PAGE>

telex or other means of electronic facsimile or telecommunication transmission,
sent by registered mail or certified mail, return receipt requested, postage
prepaid, or sent by overnight courier service, in each case to the respective
telex, telecopy or other number or address set forth for such party in Schedule
1 to the Participation Agreement, or to such other telex, telecopy or other
number or address as each party hereto may hereafter specify by notice to the
other parties hereto. Each such notice, request, demand, authorization,
direction, consent, waiver or other communication shall be effective when
received or, if made, given, furnished or filed (a) by telecopy or other means
of electronic facsimile or telecommunication transmission, when confirmed, or
(b) by registered or certified mail, three Business Days after being deposited,
properly addressed, in the U.S. mail.

      11.8  SEVERABILITY

      If any provision of this Trust Agreement shall be held invalid, illegal or
unenforceable in any respect in any jurisdiction, then, to the extent permitted
by Law, (a) all other provisions hereof shall remain in full force and effect in
such jurisdiction and (b) such invalidity, illegality or unenforceability shall
not affect the validity, legality or enforceability of such provision in any
other jurisdiction. If, however, any Law pursuant to which such provisions are
held invalid, illegal or unenforceable may be waived, such Law is hereby waived
by the parties hereto to the full extent permitted, to the end that this Trust
Agreement shall be deemed to be a valid and binding agreement in all respects,
enforceable in accordance with its terms.

      11.9  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 Section 10; and any waiver of the terms hereof
shall be effective only in the specific instance and for the specific purpose
given.

      11.10 COUNTERPARTS

      This Trust Agreement and any amendments, waivers, consents or supplements
hereto may be executed in any number of counterparts, each of which when so
executed shall be deemed to be an original, and all of which counterparts, taken
together, shall constitute one and the same instrument.

      11.11 BINDING EFFECT, ETC.

      All covenants and agreements contained in this Trust Agreement shall be
binding upon, and inure to the benefit of, Owner Trustee and its successors and
assigns, and Owner Participant and its successors and, to the extent permitted
by Section 8, assigns. Any request, notice, direction, consent, waiver or other
instrument or action by Owner Participant shall bind its successors and assigns.

      11.12 HEADINGS; REFERENCES

      The headings and the table of contents used in this Trust Agreement are
for convenience of reference only and shall not define or limit any of the terms

<PAGE>

or provisions hereof and shall not in any way affect the construction of, or be
taken into consideration in interpreting, this Trust Agreement.

      11.13 GOVERNING LAW

      THIS TRUST AGREEMENT SHALL IN ALL RESPECTS BE GOVERNED BY THE LAWS OF THE
STATE OF UTAH , INCLUDING ALL MATTERS OF CONSTRUCTION, VALIDITY AND PERFORMANCE,
WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF LAWS.


                     [This space intentionally left blank.]

<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.


                                            [                                  ]


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


                                            WELLS FARGO BANK NORTHWEST,
                                            NATIONAL ASSOCIATION


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