Document:

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                                                                   Exhibit 10.18

                                FOURTH AMENDMENT

         This Fourth Amendment is entered and made as of this 17th day of
October, 2002 (the "Amendment") as an amendment to the Service Agreement dated
as of November 11, 1997, by and between US Airways, Inc. ("US Airways") and Mesa
Airlines, Inc. as amended ("MesaJet" or "Mesa") (the "Agreement").

                                   WITNESSETH:

         WHEREAS, US Airways and Mesa have entered into the Agreement; and

         WHEREAS, US Airways and Mesa have entered into the First Amendment to
the Agreement dated as of November, 24, 1999 (the "First Amendment"); and

         WHEREAS, US Airways and Mesa have entered into the Second Amendment to
the Agreement dated as of October 6, 2000 (the "Second Amendment"); and

         WHEREAS, Mesa has entered into a Consent Agreement dated as of October
6, 2000; and

         WHEREAS, US Airways and Mesa have entered into the Third Amendment to
the Agreement dated as of October 17, 2002 (the "Third Amendment"); and

         WHEREAS, US Airways and Mesa desire to amend certain provisions of the
Agreement;

         NOW THEREFORE, in consideration of the premises and mutual covenants
hereinafter set forth and for other good and valuable consideration, the receipt
and sufficiency of which is acknowledged, and intending to be legally bound, US
Airways and Mesa hereby agree as follows:

The following is added as a new Section 5.15 of the Agreement.

         1.       Within seven (7) business days of the execution of this
Amendment, US Airways shall file with the United States Bankruptcy Court for the
Eastern District of Virginia, or any other bankruptcy court (the "Court") having
jurisdiction over the cases under Chapter 11, Title 11, of the United States
Code (the "Bankruptcy Code" of US
<PAGE>
Airways (the "Case"), a motion to assume the Agreement, and all amendments
thereto, under Section 365 of the Bankruptcy Code.

2.       The effectiveness of this Amendment shall be conditioned on and subject
to the entry of a final order (the "Order") by the Court, or any other
bankruptcy court having jurisdiction over the cases under Chapter 11 Title 11 of
the Bankruptcy Code filed by US Airways (a) authorizing and directing US Airways
to assume the Agreement, as previously amended and modified by this Agreement,
under Section 365 of the Bankruptcy Code, and (b) approving the terms of this
Amendment and authorizing and directing US Airways to enter into and be bound by
this Amendment. In the event the Order is not entered on or before December 13,
2002, this Amendment shall be null and void and of no force or effect. The Order
shall provide that US Airways' obligations under the Agreement and this
Amendment shall be post-petition, administrative obligations of US Airways under
Section 503 of the Bankruptcy Code, except for obligations that arise, or become
due and payable, after the Breach Date (as defined below) as provided below.
Notwithstanding the foregoing, in the event US Airways fails to confirm a
Chapter 11 plan of reorganization in the Case under which US Airways continues
to operate as an air carrier on substantially the same basis as the date hereof
or the Case is dismissed or converted to a case under Chapter 7 of the
Bankruptcy Code and as a result thereof US Airways suspends or discontinues
flight operations, US Airways may terminate the Agreement by providing 10 days
prior written notice of Mesa of such termination. In such event, US Airways
shall be deemed to have breached the Agreement as of the effective date of such
termination (the "Breach Date") and Mesa shall be entitled to assert, subject to
objection (x) an administrative claim for any obligations arising before the
Breach Date and (y) a general unsecured pre-petition claim for damages resulting
from such termination incurred, or for obligations that become due and payable,
after the Breach Date. Furthermore, Mesa shall refund any amounts paid to it by
US Airways on account of services to be provided for any time period after the
Breach Date within three business days of receipt of written demand from US
Airways to Mesa.

3.       Mesa agrees that it shall waive any claim to, and, upon entry of the
Order, release and hold US Airways harmless from, payments of: (a) * (the "*")
which has been
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previously invoiced to US Airways as partial payment for services performed
under the Agreement during the period October 1, 2001 through December 31, 2001;
(b) * (the "Reimbursable Expense Amount") representing certain claims presented
by Mesa and approved by US Airways for reimbursable expenses; and (c) an amount
of * related to expenses incurred during the period July 2000 to April 2002 (the
"Settlement Amount"), provided that in the event the Agreement is terminated for
any reason, other than by reason of Mesa's breach of its obligations under the
Agreement, including without limitation a termination under Section 7.2, 7.3 or
7.4 of the Agreement or a termination in the event that US Airways fails to
confirm a plan of reorganization in the Case, Mesa shall have an allowed claim
against US Airways, which in the event a plan of reorganization has not been
confirmed in the case as of such date, shall be treated as a general unsecured
pre-petition claim against US Airways, in the full amount of the *, the
Reimbursable Expense Amount, and the Settlement Amount. . In the event US
Airways breaches this Agreement, and to the extent such breach gives rise to any
pre-petition claims by Mesa against US Airways by operation of this Agreement,
Mesa shall have a period of thirty (30) days from the date of such breach to
file proofs of claim to assert such pre-petition claims against US Airways,
whether or not such breach occurs subsequent to the November 4, 2002 bar date
for filing proofs of claim.

         4.       Subject to the provisions of Paragraph 2 above, to the extent
Mesa is required to refund any compensation it has received under the *, Mesa
shall have a general post-petition administrative claim against US Airways in an
amount equal to the amount of such compensation that Mesa is required to refund.

         5.       Upon execution of an agreement between Mesa and US Airways
which contemplates * or more additional regional jets ("Fifth Amendment"), Mesa
will defer payment in an amount not to exceed * million of the Pre Bill Invoice
as referenced in the Third Amendment Section 5.8 from the first day of the
billing month to the first day of the month following the billing month. Any
amount above * million shall be paid in advance at the beginning of the month.
This payment cycle will continue until US Airways emerges from Chapter 11.
Commencing with the billing month following the emergence of US Airways from
Chapter 11, Section * of the Agreement shall be hereby
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amended such that the Pre Bill Invoice for all Mesa flying for the Service will
be paid on the * of each billing month with each payment representing * of the
Pre Bill Invoice.

6.       AUDIT: US Airways and Mesa hereby agree that US Airways will, at its
own cost and expense and within three months of executing this Amendment, retain
an independent third party auditor to implement a system audit of Mesa's
invoices to US Airways under the Agreement for the period July 2000 to April
2002 (the "Audit"), in accordance with the terms of the Third Amendment. Mesa
shall promptly provide all information necessary to the independent third party
auditor and the auditor shall complete the Audit in a timely manner. The
independent third-party auditor shall verify the calculations, statistical data
inputs and assumptions used in determining the amounts paid by US Airways to
Mesa during the period of the Audit and to determine, without taking into
consideration the above "Settlement Amount" payment *, if any amounts are owed
by one party to the other for such period. In the event that the net of any such
amounts would result in a payment from one party to the other (the "Audit
Amount"), US Airways and Mesa agree that the Audit Amount shall be the lesser
of: (x) such payment or (y) *.

         7.       Subject to the terms and conditions hereof, Mesa and US
Airways hereby consider all financial matters for billing months prior to March
1, 2002 related to the Agreement as settled and final, and for the billing
periods commencing March 1, 2002 through October, 2002 as settled and final
other than for adjustments in the normal course of business relating to
Reimbursable Expenses and Statistical True-up.

         8.       Mesa agrees that it will use its commercially reasonable
efforts to facilitate the handling of code-share passengers and the processing
of alliance partner frequent flyer miles pursuant to domestic and international
code-share alliance relationships entered into by US Airways.

Except as reflected above, the Agreement remains unchanged in all other
respects. Upon its execution, this Fourth Amendment, together with the
Agreement, will be the complete and binding understanding of the Parties with
respect to the terms and conditions of the Agreement, as amended by the terms
set forth herein.
<PAGE>
IN WITNESS WHEREOF, the parties have caused this Amendment to be executed by
their duly authorized representatives as of the day and year first above
written.

MESA AIRLINES, INC.                            US AIRWAYS, INC.

 /S/ Michael Lotz                                /S/ N. Bruce Ashby
By:  Michael Lotz                              By:  N. Bruce Ashby
Title:  President                              Title:  Sr. Vice President
                                                       Corporate Development<PAGE>
                                                                   Exhibit 10.19

                                 FIFTH AMENDMENT

         This Fifth Amendment is entered and made as of this 17th day of
October, 2002 (the "Amendment") as an amendment to the Service Agreement dated
as of November 11, 1997, by and between US Airways, Inc. ("US Airways") and Mesa
Airlines, Inc. as amended ("MesaJet" or "Mesa") (the "Agreement").

                                   WITNESSETH:

         WHEREAS, US Airways and Mesa have entered into the Agreement; and

         WHEREAS, US Airways and Mesa have entered into the First Amendment to
the Agreement dated as of November, 24, 1999 (the "First Amendment"); and

         WHEREAS, US Airways and Mesa have entered into the Second Amendment to
the Agreement dated as of October 6, 2000 (the "Second Amendment"); and

         WHEREAS, Mesa has entered into a Consent Agreement dated as of October
6, 2000; and

         WHEREAS, US Airways and Mesa have entered into the Third Amendment to
the Agreement dated as of October 17th, 2002 (the "Third Amendment"); and

         WHEREAS, US Airways and Mesa have entered into the Fourth Amendment to
the Agreement dated as of October 17th, 2002 (the "Fourth Amendment"); and

         WHEREAS, US Airways and Mesa desire to amend certain provisions of the
Agreement;

         NOW THEREFORE, in consideration of the premises and mutual covenants
hereinafter set forth and for other good and valuable consideration, the receipt
and sufficiency of which is acknowledged, and intending to be legally bound, US
Airways and Mesa hereby agree as follows:

1)       The following Section 2.1(b) is hereby added to the Agreement: SECTION
2.1(B)

         MesaJet will deploy * aircraft, or other similar aircraft subject to
         mutual agreement of the parties, under the Agreement (hereinafter
         referred to as
<PAGE>
         the "Additional Aircraft"), at financing terms and return conditions
         reasonably acceptable to US Airways and in compliance with the
         applicable provisions * protocol as ratified by US Airways ALPA on
         August 8, 2002, based on the delivery schedule attached hereto as
         Exhibit 2.1(b):

2)       Section 5.1 is amended by adding before the word "pursuant" in the
         forth line of the first paragraph "and Additional Aircraft."

3)       Section 5.2(p) "Aircraft Ownership Cost Per Month" is amended by adding
         the following paragraph to the Section:

         The Aircraft Ownership variable for the Additional Aircraft shall be
         the actual monthly lease costs for said aircraft. However, if prior to
         the execution of the documentation procuring Additional Aircraft, US
         Airways is able to arrange for Mesa to receive more favorable financial
         terms from the aircraft owner or lessor for the Additional Aircraft at
         Mesa, the more favorable financial terms will replace those
         contemplated in Section 5.2 of the Agreement (as amended by the Third
         Amendment) for the Additional Aircraft.

4)       Section 5.4(b) "Annual Wages Per Crew - Pilot" is amended by adding the
         following sentence to the Section:

         The Annual Wages Per Crew - Pilot variable will be updated to reflect
         the impact of actual pilot seniority and related pay scales related to
         the Additional Aircraft.

5)       Section 5.4(f) "Annual Wages Per FA" is amended by adding the following
         sentence to the Section:

         The Annual Wages Per FA variable will be updated to reflect the impact
         of actual flight attendant seniority and related pay scales related to
         the Additional Aircraft.

6)       Section 5.4(i) "Maintenance Per Block Hour" is amended by adding the
         following sentence to the Section:

         The Maintenance Per Block Hour variable will be adjusted to reflect
         actual third party maintenance block hour costs related to the
         Additional Aircraft, subject to mutual agreement of the parties, such
         agreement not to be unreasonably withheld by either party.

7)       Section 5.4(q) "Mesa Profit as a Percent of Total" is amended by adding
         the following sentence to the Section:
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         The Mesa Profit as a Percent Total variable for the Additional Aircraft
         shall be *.

8)       Section 5.12, "Reimbursable Expenses" is amended by adding the
         following sentence to the Section:

         For the invoiced amount related to the Additional Aircraft, U.S.
         Airways agrees to pay an administrative fee equal to *.

9)       The following Section 5.17 is hereby added to the Agreement:

         SECTION 5.17 - START-UP CREDIT

         Commencing upon the first business day of the calendar month following
         the later of: (x) the completion of Audit as defined in the Fourth
         Amendment to the Agreement; or (y) US Airways' emergence from Chapter
         11 (the "Payment Start Date"), US Airways shall pay to Mesa (or, in the
         event money is owed to US Airways, Mesa shall pay to US Airways) the
         "Startup Credit" payment, which shall be calculated as the sum of: (z)

         * to be paid by US Airways to Mesa; and (w) the Audit Amount (as
         defined in the Fourth Amendment to the Agreement, and which could
         result in a payment to either party), which Startup Credit payment
         shall be made in twelve (12) equal monthly installments.

10)      The following Section 7.6 is hereby added to the Agreement:

         SECTION 7.6 - TERM AND TERMINATION OF ADDITIONAL AIRCRAFT

         (a)      This Agreement with respect to the Additional Aircraft is
         effective as of the date and year first written above, and Services
         provided hereunder will continue, without interruption until the tenth
         (10th) anniversary of the date the first Additional Aircraft is added
         to Mesa's fleet pursuant to Section 2.1(b) of the Agreement (as amended
         by this Fifth Amendment), unless it is terminated on an earlier date
         pursuant to the provisions in Article 7 of the Agreement or as
         described in (b) as follows. US Airways, at its sole option, may extend
         the Agreement with respect to the Additional Aircraft by two (2) years
         upon written notification to MesaJet at any time up to twelve (12)
         months before the 10th anniversary of the date the first Additional
         Aircraft is added to Mesa's fleet pursuant to Section 2.1(b) of the
         Agreement (as amended by this Fifth Amendment). To accomplish an
         orderly termination of this Agreement with respect to the Additional
         Aircraft, the Parties agree that any termination of this Agreement with
         respect to the Additional Aircraft shall be on an aircraft-by-aircraft
         basis with no more than * Additional Aircraft terminated hereunder and
         returned to MesaJet each month and, to the extent necessary, the
         Parties agree to extend the term of this Agreement (but in no event
         longer than * with respect to
<PAGE>
         the Additional Aircraft to accommodate the orderly termination of the
         Services under this Agreement with respect to the Additional Aircraft.

         (b)      US Airways shall have the right, commencing at the *
                  anniversary of the date the first Additional Aircraft is added
                  to Mesa's fleet pursuant to Section 2.1(b) of the Agreement,
                  to terminate this Agreement with respect to the Additional
                  Aircraft in the event in US Airways' sole discretion subject
                  to its good faith determination that *, at any time upon three
                  hundred sixty five (365) days' prior written notice to Mesa.
                  Termination of this Agreement with respect to the Additional
                  Aircraft will not relieve either party from any obligation or
                  liability accrued hereunder prior to the time of termination.
                  To accomplish an orderly termination of this Agreement with
                  respect to the Additional Aircraft, the parties agree that any
                  such termination shall be on an aircraft-by-aircraft basis
                  with no more than * Additional Aircraft terminated hereunder
                  each month and, to the extent necessary, the parties agree to
                  extend the term of this Agreement (but in no event longer than
                  *) with respect to the Additional Aircraft to accommodate the
                  orderly termination of the Services pursuant to this Agreement
                  with respect to the Additional Aircraft. In the event of such
                  early termination, at Mesa's option, US Airways shall assume
                  payment of Mesa's lease payments for such terminated
                  Additional Aircraft and upon such assumption, may elect to
                  operate such aircraft or to cause such aircraft to be operated
                  by another party, such election to be made at US Airways'
                  discretion, until the expiration of the lease of such
                  terminated Additional Aircraft to Mesa (but in no event longer
                  than the term reviewed by US Airways at the time such aircraft
                  were first placed into the Service in accordance with Section
                  2.1(b); or other term, provided that in the event Mesa
                  undertakes to amend the term or other conditions of the leases
                  of any of the Additional Aircraft subsequent to such aircraft
                  entering the Service, such amendments shall have been approved
                  in writing by US Airways prior to their execution) and shall
                  assume the responsibility to satisfy all return condition
                  obligations pursuant to the lease of such terminated
                  Additional Aircraft to Mesa (but in no event more than the
                  obligations reviewed by US Airways at the time such aircraft
                  were first placed into the Service in accordance with Section
                  2.1(b); or other obligations, provided that in the event Mesa
                  undertakes to amend the return obligations of the leases of
                  any of the Additional Aircraft subsequent to such aircraft
                  entering the Service, such amendments shall have been approved
                  in writing by US Airways prior to their execution).

11)      Article 12 "Option for Additional Aircraft" is hereby deleted in its
         entirety.

Except as reflected above, the Agreement remains unchanged in all other
respects. Upon its execution, this Fifth Amendment, together with the Agreement,
will be the complete
<PAGE>
and binding understanding of the Parties with respect to the terms and
conditions of the Agreement, as amended by the terms set forth herein.

Subject to mutual agreement, Mesa and US Airways agree to enter into a
restatement of the terms and conditions of the Service Agreement, as amended, in
order to substitute Mesa Air Group, Inc. as the signatory party to the
Agreement.

IN WITNESS WHEREOF, the parties have caused this Amendment to be executed by
their duly authorized representatives as of the day and year first above
written.

MESA AIRLINES, INC.                            US AIRWAYS, INC.

/S/ Michael Lotz                                /S/ N. Bruce Ashby
By:  Michael Lotz                              By:       N. Bruce Ashby
Title:  President                              Title:    Sr. Vice President
                                                         Corporate Development
<PAGE>
                                    EXHIBIT A

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