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                                                                Exhibit 10.15(a)

                             LEASE SUPPLEMENT N0. 1

     THIS LEASE SUPPLEMENT NO.1, dated as of AUG 25, 1998, between McDonnell
Douglas Finance Corporation ("Lessor") and Chautauqua Airlines, Inc.
("Lessee");

                               W I T N E S S E T H

     WHEREAS, Lessor and Lessee have heretofore entered into that certain Lease
Agreement dated as of August 1, 1988 (herein called the "Lease" and the terms
defined therein being herein used with the same meaning), which Lease provides
for the execution and delivery from time to time of Lease Supplements each
substantially in the form hereof for the purpose of leasing the Aircraft under
the Lease as and when delivered by the Lessor to the Lessee in accordance with
the terms thereof;

     NOW, THEREFORE, in consideration of the premises and other good and
sufficient consideration, and pursuant to Article 2 of the Lease, the Lessor and
the Lessee hereby agree as follows:

     1.    The Lessor hereby delivers and leases to the Lessee, and the Lessee
     hereby accepts and leases from the Lessor, under the Lease Agreement, as
     herein supplemented, the following:

     (i)   Airframe: Saab Scania AB, Saab SF340A, FAA Registration N125CH,
     manufacturer's serial no, 340A-125.

     (ii)  Engines: General Electric model CT7--5A2, manufacturer's serial nos.
     GE-E-367421K and GE-E-367422K (each of which engines has 750 or more rated
     takeoff horsepower);

     (iii) Propellers: Dowty Rotol model (c)R354/4-123-F/13, manufacturer's
     serial nos. URG/2023/88 and DRG/4407/88 (each of which Propellers is
     capable of absorbing 750 or more rated takeoff shaft horsepower); and

     (iv)  Such other further and additional equipment as may be specified in
     any attached invoices.

     All the foregoing is hereinafter referred to as the "Delivered Equipment."

                                       1

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Certain portions of this exhibit have been omitted pursuant to a request for
confidential treatment under Rule 406 of the Securities Act of 1933. The
omitted materials have been filed separately with the Securities and Exchange
Commission.

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          manufacturer's serial numbers DRG/5453/88 and DRG/5454/88 (the
          "Propellers"), to which were attached the Purchase Option Agreement
          dated September 29, 1988 (the "option Agreement") between the Lessor
          as grantor and the Lessee as grantee and the Assignment of Lease
          Agreement dated as of August 25, 1988 (the "Lease Assignment") between
          the Lessee as assignor and Manufacturers Hanover Trust Company of
          California, as Trustee (the "Trustee") under the Second Amended and
          Restated Trust Agreement dated as of June 25, 1987 (the "Trust
          Agreement"), were recorded as Conveyance No. D93469; and

     (c)  Lease Supplement No. 2 dated as of September 29, 1988 (the "Sublease
          Supplement") between the Trustee as sublessor and Chautauqua Airlines,
          Inc. as sublessee (the "Sublease"), which supplemented the Lease
          Agreement dated as of August 15, 1988 (the "Sublease") between the
          Lessee as sublessor and the Sublessee to cover the Aircraft, the
          Engines and the Propellers, which was assigned by the Lessee to the
          Trustee pursuant to the Assignment and Assumption of Lease Agreement
          dated as of August 25, 1988 (the "Sublease Assignment"), was recorded
          as Conveyance No. D93470.

     Subsequent to the recordations mentioned above, we examined the records
maintained by the FAA for the Aircraft and what were represented to us by FAA
personnel as being all of the encumbrance cross-reference index cards in
existence for the Engines and the Propellers. Based upon such examination, it is
our opinion that:

     (a)  the retained legal title to the Aircraft is vested in the Lessor, with
          a Certificate of Aircraft Registration duly issued to the Trustee
          pursuant to and in accordance with the provisions of the Federal
          Aviation Act of 1958, as amended (the "Act");

     (b)  the Aircraft, the Engines and the Propellers are free and clear of any
          Liens (as such term is defined in the Lease) except such as are
          created by the Lease, as supplemented by the option Agreement and as
          assigned by the Lease Assignment, and the Sublease, as assigned by the
          Sublease Assignment and as supplemented by the Sublease Supplement;
          and

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     (c)  the FAA Bill of Sale, the Lease with the Option Agreement and the
          Lease Assignment attached and the Sublease supplement have been duly
          recorded by the FAA pursuant to and in accordance with the provisions
          of the Act.

          This opinion is subject to the same limitations and exceptions as were
set forth in the last paragraph of our opinion letter to you dated September 29,
1988, covering the Aircraft, the Engines and the Propellers.

                                             Very truly yours,
                                             /s/ Preston G. Gaddis II
                                             PRESTON G. GADDIS II
                                             For the Firm
PGG:RDJ:kh/130015
370PGG88<Page>

                                                                EXHIBIT 10.15(B)

                             LEASE SUPPLEMENT N0. 2

     THIS LEASE SUPPLEMENT N0. 2, dated as of September _, 1988, between
Manufacturers Hanover Trust Company of California, not in its individual
capacity but solely as owner trustee under the Second Amended and Restated Trust
Agreement dated as of June 25, 1987 ("Lessor") and Chautauqua Airlines, Inc.
("Lessee");

                               W I T N E S S E T H

     WHEREAS, Lessor (by assignment from McDonnell Douglas Finance Corporation
pursuant to an Assignment and Assumption of Lease Agreement dated as of August
15, 1988 which has been filed with the Federal Aviation Administration) and
Lessee are parties to that certain Tease Agreement dated as of August 15, 1988,
which Lease Agreement together with Lease Supplement No. 1 thereto (herein
collectively called the "Lease" and the terms defined therein being herein used
with the same meaning) was recorded by the Federal Aviation Administration on
August 26, 1988 as conveyance No. K80051 and which Lease provides for the
execution and delivery from time to time of Lease Supplements each substantially
in the form hereof for the purpose of leasing the Aircraft under the Lease as
and when delivered by the Lessor to the Lessee in accordance with the terms
thereof;

     NOW, THEREFORE, in consideration of the premises and other good and
sufficient consideration, and pursuant to Article 2 of the Lease, the Lessor and
the Lessee hereby agree as follows:

     1.    The Lessor hereby delivers and leases to the Lessee, and the Lessee
hereby accepts and leases from the Lessor, under the Lease Agreement, as herein
supplemented, the following:

     (i)   Airframe: Saab Scania AB, Saab SF340A, FAA Registration N128CH,
     manufacturer's serial no. 340A-128.

     (ii)  Engines: General Electric model CT7-5A2, manufacturer's serial. nos.
     GE-E-367409K and GE-E-367439K (each of which engines has 750 or more rated
     takeoff horsepower);

     (iii) Propellers: Dowty Rotol model (c)R354/4-123-F/13, manufacturer's
     serial nos. DRG/5453/88 and DRG/5454/88 (each of which Propellers is
     capable of absorbing 750 or more rated takeoff shaft horsepower); and

     (iv)  Such other further and additional equipment as may be specified in
     any attached invoices.

     All the foregoing is hereinafter referred to as the "Delivered Equipment."

                                       1

------------
Certain portions of this exhibit have been omitted pursuant to a request for
confidential treatment under Rule 406 of the Securities Act of 1933. The
omitted materials have been filed separately with the Securities and Exchange
Commission.

<Page>

     2. The Delivery Date of the Delivered Equipment is the date of this Lease
Supplement set forth in the opening paragraph hereof.

     3. Equipment Cost for each of the delivered Aircraft (including Airframe,
Engines, and Propellers) is [*].

     4. Term for the Delivered Equipment shall commence on the Delivery Date
therefor and shall conclude on the close of business on September 30, 2002,
subject to any early termination provisions invoked in accordance with the
Lease.

     5. The Lessee hereby confirms its agreement to pay the Lessor Interim Rent,
Basic Rent and Supplemental Rent for the Delivered Equipment, throughout the
Term therefor in accordance with the Lease. The Interim Rent for the Delivered
Equipment shall be payable on October 1, 1988 in an amount equal to $________.
The Interim Rent shall be allocated, for Federal income tax purposes, to the
monthly periods immediately before the date it is due. The Basic Rent for the
Delivered Equipment shall be payable in 168 consecutive monthly installments,
payable in advance, the first installment of which is due and payable October 1,
1988, and subsequent installments shall be payable on the first day of each
month throughout the Term. [*] Each installment of Basic Rent shall be
allocated, for Federal income tax purposes, to the monthly period immediately
after the date it is due.

     All payments of Rent under the Lease shall he paid to Lessor by wire
transfer of immediately available funds on or before the due dates therefor to
Wells Fargo Bank, N.A., San Francisco Main Office, Credit: MANCAL-Trust Aid
Control, Account No. 0001-179936.

     6. The Lessee hereby confirms to the Lessor that it will, as soon as
practicable, mark the Delivered Equipment as showing all interests thereto in
accordance with the terms of the Lease and that the Lessee has accepted the
Delivered Equipment for all purposes hereof and of the Lease, including its
being airworthy, in accordance with specifications, in good working order and
repair and without defect in title, condition, design, operation or fitness for
use, whether or not discoverable by Lessee on the date hereof, and free and
clear of all Liens, except for those contemplated by the Lease, provided,
however, that nothing contained herein or in the Lease shall in any way diminish
or otherwise affect any right the Lessee or the Lessor may have with respect to
the Delivered Equipment against the manufacturer thereof, or any subcontractor
or supplier of the manufacturer thereof.

                                        2

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* Confidential

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     7. This Lease Supplement shall in all respects be governed by, and
construed in accordance with, the laws of the State of New York, including all
matters of construction, validity and performance.

     IN WITNESS WHEREOF, Lessor and Lessee have each caused this Lease
Supplement to be duly executed by their authorized officers as of the day and
year first above written.

                                       Manufacturers Hanover Trust Company of
                                           California,
                                       not in its individual capacity but solely
                                       as owner trustee under the Second Amended
                                       and Restated Trust Agreement dated as of
                                       June 25, 1987, AS AMENDED
                                       By:
                                            -----------------------------------
                                       Its:
                                            -----------------------------------

                                       Chautauqua Airlines, Inc.,
                                         as Lessee

                                       By:  /s/ Timothy Coon
                                            -----------------------------------
                                       Its: President
                                            -----------------------------------

                                        3
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                                   EXHIBIT B1
                              STIPULATED LOSS VALUE
         (FOR ALL ITEMS OF EQUIPMENT COVERED BY LEASE SUPPLEMENT NO. 2)

[CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT]

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