Document:

<PAGE>
                                                                   Exhibit 10.13

                               AMENDMENT NO. 2 TO
                               CODESHARE AGREEMENT

      This Amendment No. 2 (the "Amendment") is made and entered into as of
August 1, 2002 (the "Effective Date"), by and between Frontier Airlines, Inc.
("Frontier"), a corporation organized under the laws of Colorado, and Mesa
Airlines, Inc. ("Mesa"), a corporation organized under the laws of Nevada.

RECITALS:

      A.    Mesa and Frontier have entered into a Codeshare Agreement, dated as
            of September 4, 2001 (the "Codeshare Agreement"). All capitalized
            terms used in this Amendment, but not defined herein, shall have the
            meaning given to such terms in the Codeshare Agreement.

      B.    Both Mesa and Frontier recognize the importance of maintaining high
            levels of service in order to attract and retain passengers.

      C.    One such way to attract and retain passengers is to operate the
            scheduled flights and do so on-time.

DEFINITIONS:

      A.    Completion Benchmark: Frontier Airlines' completion rate for its
            network-wide operations during the same month it is used to
            benchmark Mesa's performance.

      B.    On-time Benchmark: Frontier Airlines' on-time departure performance
            rate for its network-wide operations during the same month it is
            used to benchmark Mesa's performance. An on-time departure is when
            an aircraft leaves the gate between zero to fifteen minutes after
            scheduled departure, otherwise the departure is not considered
            on-time.

      C.    Incentive Penalty: The amount to be paid as a penalty for the
            difference between the actual number of flights completed or
            performed on-time and the Completion or the On-time Benchmarks.

NOW, THEREFORE, in consideration of the recitals and for other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, Mesa
and Frontier agree to amend the Codeshare Agreement by adding the following sub
section as follows:

14.2 (d) Fees will be assessed to incentivise Mesa to operate those flights
     marketed under the Frontier Airlines (F9*) code in a manner equal or
     exceeding the performance of Frontier Airlines' operations. Mesa shall
     be penalized if performance falls below either the Completion Benchmark
     or the On-time Benchmark for any given month.

      1. Determination of number of flights to be penalized

      a)    In order to determine if Mesa flights fall below the completion
            levels required by the Codeshare Agreement, Frontier will first
            multiply the Completion Benchmark by the total number of Mesa
            scheduled departures
<PAGE>
            for the month then subtract the number of Mesa flights operated
            during the month. If the result is a positive number, this number of
            flights to be penalized for failing to meet the completion
            performance requirements (see example in section 1(c)).

      b)    In order to determine if Mesa flights fall below the on-time levels
            required by the Codeshare Agreement, Frontier will first multiply
            the On-time Benchmark by the total number of Mesa scheduled
            departures for the month then subtract the number of Mesa flights
            operated on-time during the month. If the result is a positive
            number, this is the number of flights to be penalized for failing to
            meet the on-time performance requirements (see example in section
            1(c)).

      c)    Sample Calculations

            1.    By way of illustration, the following is a sample Completion
                  Penalty Calculation. If, for example, in the month of August,
                  Frontier completes [***] of its flights, the Completion
                  Benchmark for August is [***}. Further, if Mesa has scheduled
                  [***] flights for that month, it needs to complete a minimum
                  of [***] flights during the month of August, it will pay an
                  Incentive Penalty for the thirteen flights it failed to
                  complete.

            2.    By way of illustration, the following is a sample On-time
                  Penalty Calculation. If, for example, in the month of August,
                  Frontier performs [***] of its flights on-time, the On-time
                  Benchmark for August is [***]. Further, if Mesa has scheduled
                  [***] flights for that month, it needs to complete a minimum
                  of [***] flights on-time in order to meet the On-time
                  Benchmark. If Mesa completes only [***] flights on-time during
                  the month of August, it will pay an Incentive Penalty for the
                  one hundred flights it failed to complete on-time.

      2. Penalty fees

            a)    For each flight below the Completion Benchmark, Mesa shall pay
                  Frontier [***]. This penalty will double for each consecutive
                  month Mesa fails to meet the Completion Benchmark.

            b)    For each flight below the On-time Benchmark, Mesa shall pay
                  Frontier [***]. This penalty will double for each consecutive
                  month Mesa fails to meet the On-Time Benchmark.

            c)    The maximum fine for each month will not exceed [***].

            d)    In the event that Mesa's completion rate exceeds the
                  Completion Benchmark by two or more percentage points and
                  Mesa's on-time performance exceeds the On-Time benchmark by
                  two or more percentage points in the same month, Frontier will
                  pay Mesa [***]

      3. Settlement of Penalty fees

<PAGE>

            a)    Penalties are only to be paid if Mesa falls below the
                  benchmark performance set by Frontier Airlines.

            b)    Mesa is to pay any penalties for performance which drops below
                  the benchmark requirements within 30 days of receipt of
                  Frontier's notice informing Mesa that it failed to meet the
                  benchmark.

      4. Exchange of Performance data.

            Frontier and Mesa are to exchange performance figures weekly
            relative to their performance, and specifically for the percentage
            of departures leaving on-time within 15 minutes of schedule and
            percentage of scheduled flights departed.

      5.    This Amendment shall be in full force and effect during the entire
            term of the Codeshare Agreement.

                                              MESA AIRLINES, INC.

                                              By:     /S/ Mike Lotz
                                                 -------------------------------
                                              Name:
                                                   -----------------------------
                                              Title:      President
                                                    ----------------------------

                                              FRONTIER AIRLINES, INC.

                                              By:     /S/ Sean Menke
                                                 -------------------------------
                                              Name:
                                                 -------------------------------

                                               Title:   VP Marketing & Planning
                                                    ----------------------------<PAGE>
                                                                   Exhibit 10.15

                                 FIRST AMENDMENT

This First Amendment is entered and made as of November 24, 1999 (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.
("MesaJet") (the "Agreement").

                                   WITNESSETH:

WHEREAS,  US Airways and MesaJet have entered in the Agreement; and

WHEREAS, on or about the 15th day of June, 1999, US Airways and MesaJet entered
into a Memorandum of Understanding relating to the amendment of the Agreement in
certain respects; and

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

NOW THEREFORE, in consideration of the premises and mutual covenants hereinafter
set forth and for good and valuable consideration, the receipt and sufficiency
of which is acknowledged, US Airways and MesaJet hereby agree as follows:

      1. Exhibit 2.1 of the Agreement is hereby amended by adding the following
to the list of operational aircraft set forth therein:

<TABLE>
<CAPTION>
       Date                                   Number of Operational Aircraft
       ----                                   ------------------------------
<S>                          <C>              <C>
       April                 1999                          *
       May                   1999                          *
       September             1999                          *
       April                 2000                          *
       April                 2000                          *
       April                 2000                          *
       June                  2000                          *
       July                  2000                          *
       August                2000                          *
       September             2000                          *
       September             2000                          *
       October               2000                          *
       November              2000                          *
       December              2000                          *
       January               2000                          *
       February              2001                          *
</TABLE>
<PAGE>
      US Airways acknowledges that changes in the delivery schedule may arise
      due to circumstances beyond MesaJet's control, including, without
      limitation, manufacturing delays, FAA or other regulatory delays or other
      operational delays. MesaJet will make every reasonable effort to provide
      as much advance notice to US Airways of such a change in the delivery
      schedule as set forth in Exhibit 2.1. Under no circumstances will MesaJet
      be liable to US Airways in any manner whatsoever for damages claimed by US
      Airways or claims made against US Airways, resulting from a change in the
      delivery schedule set forth in this Exhibit 2.1 when delays are beyond
      MesaJet's reasonable control.

2.    A new subsection 2.1(a) is hereby added to the Agreement as follows: "(a)
      The in-service target date for Aircraft deliveries * in paragraph 1 of
      this First Amendment will be on or about the 15th day of the month
      indicated therein. Notwithstanding the preceding sentence, in the event
      there are two or more deliveries in a given month, the in-service date for
      the second aircraft will be on or about the 21st day of the month and the
      in-service date for the third aircraft will be on or about the 30th day of
      the month. MesaJet will inform US Airways of the exact in-service dates
      for each month ninety (90) days prior to first day of the in-service month
      indicated."

3.    A new subsection 2.1(b) is hereby added to the Agreement as follows:
      "Notwithstanding the listing of aircraft numbered * in Schedule 2.1,
      attached hereto and made a part hereof, such aircraft will only be
      accepted by US Airways to the extent that fleet growth in the US Airways
      mainline jet network allows greater than thirty-five (35) regional jets to
      be operated with the US Airways code pursuant to its labor agreement scope
      clause. However, if fleet growth in the US Airways mainline jet network
      does not reach a level to allow greater than thirty-five (35) regional
      jets to be operated with the US Airways code, and provided that US Airways
      gives at least three months written notice, MesaJet will not be obligated
      to provide, and US Airways will not be obligated to accept the additional
      Aircraft numbered *."
<PAGE>
4.    New subsections 2.2(a), (b), and (c) are added to the Agreement as
      follows:

      "(a) With the exception of Aircraft Numbered * listed in paragraph number
      1 of this First Amendment, the additional Aircraft referenced in that
      paragraph will be a different model from the current regional jets MesaJet
      operates as US Airways Express under the Agreement. The additional
      Aircraft are * aircraft. US Airways hereby allows MesaJet to swap regional
      * currently in service with US Airways under the Agreement into *, as long
      as the total number of regional jets MesaJet has in service with US
      Airways is not reduced as a result of such aircraft swap.

      (b) MesaJet will have the right to perform such aircraft swaps referenced
      in subsection 2.2 (a), above, upon no less than ninety (90) days notice
      prior to the first day of the month such swap is contemplated to occur. At
      such time US Airways and MesaJet will jointly restructure the MesaJet
      regional jet schedule to accomplish such swap in a manner to minimize any
      adverse impact on aircraft utilization and on US Airways passengers.

      (c) US Airways will provide reasonable assistance to MesaJet in meeting
      the FAA requirements necessary to add the new * onto the MesaJet operating
      certificate. US Airways will provide a single point of contact US Airways
      employee to coordinate efforts within US Airways and interface with
      MesaJet on the new * aircraft, including training and proving run
      requirements associated with the addition of such aircraft."

      5. Section 2.7 is hereby amended by deleting the word "thirteenth" in the
ninth line of that Section, substituting the word "seventeenth" in lieu thereof,
and inserting the parenthetical "(a "Spare Aircraft")" after the word "aircraft"
near the end of that line.

6.    A new section 2.9 is hereby added to the Agreement as follows:

      "2.9 US Airways and MesaJet will cooperate to develop ways to reduce
      damage to Aircraft caused by impacts from ramp equipment, such as jet
      bridges, baggage carts,
<PAGE>
      GPU and air conditioning carts and deicing equipment operated by US
      Airways personnel."

7.    A new section 2.10 is hereby added to the Agreement as follows: "2.10 US
      Airways will coordinate schedule planning with MesaJet to minimize flight
      crew and maintenance costs, subject to meeting US Airways reasonable
      marketing objectives."

8.    A new subsection 5.2(a) is hereby added to the Agreement as follows: "(a)
      Notwithstanding the RJ Model referenced in section 5.1 above, US Airways
      will adjust the reimbursement for * according to the following:

      (i)   *.

      (ii)  Effective as of April 1. 1999, to the extent MesaJet operates
            greater than * Aircraft under this Agreement, US Airways will * per
            Aircraft than the monthly ownership costs contained in the RJ Model.
            In addition, such ownership costs will be subject to adjustments due
            to changes in interest rates incurred in financing such Aircraft.
            Such adjustments due to changes in interest rates will be in
            accordance with the table attached hereto as Appendix A.

      (iii) The interest rate referenced in subsection 5.2 (a) (ii) above, is
            primarily predicted upon the * providing the debt financing
            economically necessary for support of the *. In the event * fails to
            provide such debt for a given Aircraft, then (a) MesaJet's
            obligation to supply and US Airways obligation to accept such
            additional Aircraft is suspended, and (b) US Airways and MesaJet
            will cooperated to obtain alternative financing from * at a rate
            acceptable to both Parties.

      (iv)  US Airways will increase reimbursement for MesaJet Crew costs by *.
            Such adjustment will be amended by mutual agreement of the Parties
            at the end of the sixth month following the execution of this
            Amendment, and every six months thereafter, based on increases and
<PAGE>
            decreases in MesaJet's actual flight training costs (excluding pilot
            salaries)."

     9. Sections 5.4 and 5.5 of the Agreement are hereby deleted in their
entirety and US Airways hereby * and will eliminate the * from the date hereof
and throughout the remainder of the term of the Agreement. US Airways will
reimburse MesaJet the full amount withheld for services provided during 1999.

      10. Section 7.1 of the Agreement is hereby deleted in its entirety and the
following is substituted in lieu thereof:

                  "7.1 This Agreement is effective as of the date and year first
                  written above, and services provided hereunder will continue,
                  without interruption for a period * from the in-service date
                  of the first *, unless it is terminated on an earlier date
                  pursuant to the provisions of this Article 7. US Airways will
                  have the right to extend the term on each Aircraft by *."

      11. Section 7.4 of the Agreement is hereby deleted in its entirety.

      12. Section 8.1 of the Agreement is hereby amended by changing "*" and "*"
in line one to "*" and "*", respectively.

      13. Section 8.2 of the Agreement is hereby amended by changing "arrival"
in line one to "*".

      14. A new subsection 8.3 is hereby added to the Agreement as follows:

"8.3 In the event that an aircraft used by MesaJet to perform services called
for in this Agreement is damaged during the execution of agreed to ground
support functions set forth in Section 4.3 of the Agreement by a US Airways
employee, or an individual contracted by US Airways to perform such ground
support services, and such damage is sustained while the aircraft is parked or
being pushed or towed by said employee or contract individual, and
<PAGE>
such damage occurs while the aircraft is not being operated by a MesaJet
employee or individual contracted by MesaJet to perform services for MesaJet,
then the calculations contained in this Article 8 will be modified as follows:

            The number of scheduled flights for the month will be reduced by *.
            This modification to the calculation of performance will only be
            applied if US Airways is notified in writing within one business day
            of the date on which such damage occurs of: i) the time, place and
            circumstances surrounding the damage; ii) the expected flight
            adjustments/cancellations made or required due to the out of service
            aircraft and; iii) the estimated return to service date of the
            damaged aircraft.

            15. A new subsection 8.4 is hereby added to the Agreement as
            follows:

"8.4 Both parties agree that attrition of pilots is a normal part of the
planning and execution of a regional jet operation. Further both parties
understand that from time to time, the pilot hiring at US Airways may be greater
than expected and that the increase in US Airways hiring may affect the
attrition rate of active Mesa pilots. Since a higher than expected attrition
rate may affect MesaJet's operating performance, the parties agree that in the
event that the following conditions exist, then the calculations contained in
this Article 8 will be modified as set forth below:

      (a)   Triggering Event:

      If within a given month, US Airways hires an extraordinary number of
      active Mesa pilots, as defined below, then the calculations contained in
      this Article 8 will be modified. For use within this section the following
      definitions will apply:

                  1. The act of hiring an Mesa pilot will be defined as the
                  successful completion by an active Mesa pilot of the total US
                  Airways pilot employment process up to and including the
                  sign-on process and the attendance at the first day of
                  training.

                  2. (a) The number of active Mesa pilots hired by US Airways
                  will be deemed to be extraordinary if: i.) Mesa's pilot
                  attrition rate to all certified
<PAGE>
    non-Mesa carriers for any given month increases * over the average attrition
    rate for the preceding six months; ii)US Airways' hiring of Mesa pilots in
    any given month exceeds by * the average number of Mesa pilots hired in the
    preceding six months, and iii) the actual number of Mesa pilots hired as a
    result of the * increase in Mesa's pilot attrition rate referenced in
    2(a)(i) above.

    (b) Subsequent to the occurrence of a triggering event, as defined in
    Section 8.4 (a), above, Mesa's attrition rate for any given month shall be
    calculated using the attrition rate for the month immediately preceding the
    triggering event. Such attrition rate shall remain Mesa's average attrition
    rate for the preceding * months, for purposes of the next two subsequent
    monthly calculations of Mesa's pilot attrition rate, or until the actual
    number of Mesa pilots hired by US Airways in a given month returns to or
    falls below the actual number for the month immediately preceding the
    triggering event.

    3. An active Mesa pilot will be defined as any Mesa pilot who is currently a
    certified Captain or First Officer.

16. A new subsection 8.5 is hereby added to the Agreement as follows:

    "8.5 Modification of the Article 8 Calculations

    Once it has been mutually agreed that a triggering event, as described in
Section 8.4 (a), above, has occurred, then the monthly calculations in this
Article 8 will be modified for the month of the triggering event and the next
month in the following manner:

(a) The number of scheduled flights that is used to calculate the completion
    performance measures will be reduced *. The number of normally experienced
    flight crew cancellations will be determined by *.
<PAGE>
(b)   The number of scheduled flights that is used to calculate the arrival
      performance measures will be reduced by *. The number of normally
      experienced flight crew arrival delays will be determined by *."

17.   A new section 12.3 is hereby added to the Agreement as follows;

      "12.3 US Airways will have the right of first refusal on * groups of *
      supplemental Aircraft * that MesaJet has on firm order (the "Conditional
      Aircraft"). Such rights of first refusal will expire *. The delivery dates
      of such Conditional Aircraft are set forth below.

<TABLE>
<CAPTION>
                          Aircraft Number         Delivery Date
                          ---------------         -------------
<S>                      <C>                      <C>
        Block One                 *               May              *
                                  *               September        *
                                  *               November         *
                                  *               December         *
                                  *               April            *
                                  *               May              *
                                  *               June             *
                                  *               June             *
</TABLE>

      (a)   In the event US Airways exercises its right to one or more of the
            Conditional Aircraft, then within one year of such exercise, the
            Parties will work together to determine whether and if so, which
            Conditional Aircraft will be considered as a second Spare Aircraft.
            Such determination will be based upon completion and on-time
            statistics of the fleet. Either Party will have the right to
            determine whether a second Spare Aircraft is necessary after the
            delivery of the first Conditional Aircraft. The Parties will
            mutually agree on the timing of the introduction of the second Spare
            Aircraft.
<PAGE>
18.   A new subsection 12.4 is hereby added to the Agreement as follows:

      "12.4 MesaJet has additional aircraft on option order at a rate * Section
      12.3, above ("Option Aircraft"). MesaJet's rights to the Option Aircraft
      are *. US Airways may, by giving written notice one month prior to the
      Notice Period to MesaJet, direct MesaJet to increase the number of
      Aircraft ordered beyond *. In the event Us Airways foregoes exercising
      greater than * consecutive blocks of Option Aircraft, then US Airways will
      forego rights to *. In the event US Airways directs MesaJet to increase
      the number of Aircraft ordered beyond *, such Option Aircraft will be
      delivered to US Airways in accordance with the schedule attached hereto as
      Exhibit B. The schedule set forth in Exhibit B is indicative only and is
      subject to change. However, MesaJet will use all reasonable efforts to
      adhere to said schedule *."

Except as reflected above, the Agreement remains unchanged in all other
respects. Upon its execution, this First 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.

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

MESA AIRLINES, INC.                                  US AIRWAYS, INC.

/S/ William P. Kostel                             /S/ Thomas M. Hanley
---------------------                          ---------------------------------
By:                                            By:      Thomas M. Hanley
Title:   Vice President - Planning             Title:   Vice President
                                                        US Airways Express
<PAGE>
                                   Appendix A
                   OWNERSHIP REIMBURSEMENT ADJUSTMENT SCHEDULE

<TABLE>
<CAPTION>
             Reference Interest            Ownership
             RATE (%)                      Adjustment
             --------                      ----------
<S>                                        <C>
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
             *                               *
</TABLE>

*Where Reference Interest Rate is: Five Year LIBOR as published on Reuters
Service under code USD5YDHBEL
<PAGE>
                                   APPENDIX B
                            OPTION AIRCRAFT SCHEDULE

<TABLE>
<CAPTION>
Option                                             Option Notice
Number   Aircraft Number   Delivery Month-Year      Month-Year
------   ---------------   -------------------      ----------
<S>      <C>               <C>                     <C>
*        Aircraft #*       July *                    December *
*        Aircraft #*       August *                  December *
*        Aircraft #*       September *               December *
*        Aircraft #*       October *                 December *
*        Aircraft #*       November *                December *
*        Aircraft #*       January *                 May *
*        Aircraft #*       February *                May *
*        Aircraft #*       March *                   May *
*        Aircraft #*       April *                   May *
*        Aircraft #*       June *                    October *
*        Aircraft #*       August *                  October *
*        Aircraft #*       September *               October *
*        Aircraft #*       October *                 March *
*        Aircraft #*       November *                March *
*        Aircraft #*       December *                March *
*        Aircraft #*       January *                 March *
*        Aircraft #*       March *                   August *
*        Aircraft #*       April *                   August *
*        Aircraft #*       May *                     August *
*        Aircraft #*       June *                    August *
</TABLE>

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00046-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00046-of-00352.parquet"}]]