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                                                                   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
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            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

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