Document:

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                                                                   EXHIBIT 10.23

                                                     United Contract Nbr. 155716

                                    ZK/UNITED
                            CODE SHARE AND REGULATORY
                       COOPERATION AND MARKETING AGREEMENT

This Agreement is made and entered into by and between UNITED AIR LINES, INC.,
("UA") with its principal place of business at 1200 East Algonquin Road, Elk
Grove Township, Illinois 60007 and GREAT LAKES AVIATION Ltd. ("ZK") with its
principal place of business at 1022 Airport Parkway, Cheyenne, Wyoming 82001,
each or both parties individually or collectively referred to as "Carrier" or
"Carriers" respectively.

1.     INTRODUCTION
       ZK and UA are entering into this Agreement in order to increase each
       Carrier's opportunities to offer competitive and cost effective air
       transportation services between points in the United States. Further, ZK
       and UA wish to improve the quality of the interline air transportation
       and cargo services they now offer so as to increase the use of those
       services by the traveling and shipping public. This Agreement establishes
       binding obligations between the Carriers, expresses the Carriers
       intentions, and sets forth a framework that provides the basis to
       accomplish these goals through subsequent agreements and activities.

2.     UNDERLYING OPERATIONAL CONCEPT
       The Carriers will use a phased approach to develop and implement parallel
       marketing and operational programs to create new, value added passenger
       and cargo services and cost efficiencies by taking advantage of each
       Carrier's inherent market strengths. The transition from a United Express
       arrangement to codeshare relationship will extend until ZK has procured
       and installed the necessary automation to support the operation as an
       independent business entity. This must be completed no later than June 7,
       2002 and be hosted on a system which is technically capable of all the
       required interfaces with UA's automation systems.

3.     OBJECTIVES OF THE ZK/UA RELATIONSHIP
       Through development of the operational relationship contemplated by this
       Agreement, subject to any and all necessary governmental and regulatory
       approvals, ZK and UA intend to implement Code Share operations as defined
       in Article 4A and further described in Attachment 1, Sections A and B.

       This Agreement is not intended to restrict either Carrier's rights to
       pursue, either independently or collectively, additional access between
       any points through route acquisition.

4.     PROGRAMS
       The Carriers will develop and implement specific programs to support the
       objectives defined by this Agreement. The Attachments to this Agreement
       outline specific actions and responsibilities for implementing these
       programs. Each of the programs may be

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       incorporated into an existing ZK/UA contract or a new contract, as
       appropriate. In summary, subject to any and all applicable governmental
       laws, rules and regulations, these programs are:

       A.     CODE SHARE
              The Carriers intend to develop, in a phased approach, operations
              which include using UA's two-letter airline designator code on the
              following routes, as further specified in Attachments 1 and 1A
              ("Code Share"):

                     - To and from points within the UA's system in the US.

       B.     CODE SHARE EMERGENCY PROCEDURES
              In the event of an incident involving a Code Share flight, both
              Carriers agree to implement the emergency procedures specified in
              Attachment 2.

       C.     REGULATORY COOPERATION
              The Carriers will work together to secure the underlying
              governmental and other approvals necessary to implement this
              marketing relationship.

       D.     PUBLISHED FARES
              The carriers agree to participate in each others' published fares.

       E.     PRORATES                 (Attachment 3)
              ZK and UA will provide access to each other's system by
              maintaining the current standard prorate methodology
              (straight-rate proration) to support the overall program and to
              stimulate incremental traffic from ZK to UA, and UA to ZK. This
              will include special reciprocal protection for ZK or UA passengers
              on delayed, canceled or oversold flights.

       F.     FREQUENT FLYER           (Attachment 3)
              The Carriers shall participate in each other's frequent flyer
              programs. This participation will be exclusive as it relates to
              ZK's participation in the frequent flyer program of any U.S. based
              transportation company.

       G.     PREFERENTIAL SELLING
              The Carriers will implement procedures at their respective
              reservations sales offices to sell the other Carrier, on a "second
              to on-line" basis and in lieu of competitive off-line offerings in
              the agreed Code Share markets.

       H.     SALES
              With regard to Inventory Management for Code Share flights the
              Carriers acknowledge and agree that this Agreement does not
              provide for guaranteed block space reservations. Accordingly,
              neither UA nor ZK is purchasing or guaranteeing the seats
              allocated to it by the other. ZK and UA shall each manage, market
              and sell seats on the Code Share flights under its own respective
              airline designator code. The Carriers agree to communicate as
              necessary to facilitate such an arrangement, which will be
              phased-in in conjunction with ZK's purchase of automation
              equipment (CRS).

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       I.     JOINT SERVICE FEATURES           (Attachment 4)
              (1)    Fully Automated One-Stop Check-In
                     Both Carriers shall develop this capability using
                     international automated through check in (IATCI), to
                     provide passengers the convenience of checking in at
                     selected UA, UA Express, or ZK airport ticket counters and
                     receiving seat assignments, boarding cards, and Frequent
                     Flyer credit for their ZK/UA flights as appropriate. One
                     stop check-in also includes complete document verification
                     and baggage check to final destination.
              (2)    Improved Scheduling
                     The Carriers shall review their schedules to maximize, as
                     practicable, convenient connections to or from UA and ZK at
                     all common hubs in the U.S.
              (3)    Inflight Product Coordination
                     The Carriers shall evaluate the degree of coordination
                     required, including announcements, on code share flights.
              (4)    Seamless Transfer
                     The Carriers shall use reasonable efforts to expedite the
                     ransfer of all passengers and baggage between themselves,
                     as practicable, at all common hubs through development of a
                     shorter than standard connection time, including all
                     reasonable communications necessary to facilitate this
                     objective.
              (5)    Group Procedures
                     Groups shall be booked through each carrier's group desks.
              (6)    Air Cargo Service
                     The Carriers shall review cargo activities to investigate
                     what opportunities may exist to offer competitive and cost
                     effective air cargo services between points in the United
                     States. Further, ZK and UA shall cooperatively endeavor to
                     improve the quality of air cargo transportation to the
                     shipping community. The Carriers shall strive to sell the
                     other Carrier, on a "second to on-line" basis, and in lieu
                     of competitive off-line offerings.

       J.     DISTRIBUTION                     (Attachment 5)
              (1)    Display Improvement
                     To the extent permitted by applicable law and regulations,
                     UA and ZK shall provide preferential display of their
                     connecting flights in their respective internal reservation
                     systems and direct access displays provided through
                     computerized reservations systems.
              (2)    Quality Control
                     ZK and UA shall each use its best, commercially reasonable
                     efforts to ensure that the other party's flights, connect
                     points, fares, and rules both on-line and between ZK/UA are
                     included in each Carrier's respective host and affiliated
                     CRS system data base and are eligible for display subject
                     to system constraints and applicable laws and regulations.

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              (3)    Preferential Selling
                     The Carriers shall implement procedures at their respective
                     reservations sales offices to sell the other Carrier, on a
                     "second to on-line" basis and in lieu of competitive
                     off-line offerings in the agreed code share markets.

       K.     AIRCRAFT SECURITY
              The Carriers shall endeavor to agree upon a mutually satisfactory
              aircraft flight security program in accordance with FAA
              requirements.

5.     TERM
       This Agreement is effective as of May 1, 2001 and will continue
       thereafter for three (3) years; provided, however, that this Agreement
       may be terminated by either party at that party's election upon 360 days
       prior written notice.

6.     COMPLIANCE WITH GOVERNMENT AND SAFETY REQUIREMENTS
       A.     The Carriers represent and warrant that all air transportation
              services performed by it pursuant to this Agreement or otherwise
              will be conducted in full compliance with all applicable federal,
              state and local laws, statutes, orders, rules; and regulations.

       B.     The Carrier that originates the customer travel (provides all
              boarding passes and checks the customer luggage to his final
              destination) will assure that the customer is properly documented
              for entry into the destination country and properly documented for
              any transit points enroute. Any fines, penalties, deportation and
              detention expenses resulting from violations of government entry
              or transit requirements, even for passengers that willfully engage
              in illegal entry tactics, shall be the sole responsibility of the
              Carrier that originates the customer travel and such Carrier shall
              be considered an Operating Carrier pursuant to paragraph 15, and
              shall indemnify the other Carrier.

       C.     ZK represents and warrants that it has successfully undergone an
              FAA safety audit satisfactory to UA prior to ZK's execution of
              this Agreement and further warrants that it shall maintain
              compliance with the requirements of such audit. Any failure to
              maintain compliance shall immediately be brought to UA's attention
              along with corrective actions taken or a corrective action plan.
              Any non-compliance not promptly corrected to UA's satisfaction or
              repeated noncompliance shall be grounds for termination by UA
              without further liability, but with reservation of all other
              rights and remedies available to UA. Additional safety review
              audits may be required at UA's discretion and ZK shall cooperate
              with all such audits.

7.     EXCLUSIVITY
       This Agreement is non-exclusive and does not preclude either UA or ZK
       from entering into or maintaining existing marketing relationships,
       including code sharing, with other Carriers. Notwithstanding the
       preceding sentence, this agreement is exclusive as it

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       relates to each Carrier's participation in code sharing, on the flights
       described in Attachment 1.

8.     TRADEMARKS
       Neither Carrier will use any trademark, trade name, logo, or service mark
       of the other without the prior written consent of the other.

9.     CONFIDENTIALITY
       A.     Subject to Articles 9B, 9C and 9D, and except in any proceeding to
              enforce any of the provisions of this Agreement, neither party
              will, without the prior written consent of the other, use,
              publicize or disclose to any third party, either directly or
              indirectly, any of the following (hereinafter "Confidential
              Information"):
              (1)    this Agreement or any of the terms or conditions of this
                     Agreement; or
              (2)    any confidential or proprietary information or data, either
                     oral or written, received from and designated as such by
                     the disclosing Carrier.

       B.     If either Carrier is served with a subpoena or other legal process
              requiring the production or disclosure of any Confidential
              Information, then that Carrier, before complying, will immediately
              notify the non-disclosing Carrier and the non-disclosing Carrier
              shall have a reasonable period of time to intervene and contest
              disclosure or production.

       C.     If a governmental authority requests either Carrier to produce or
              disclose to the authority this Agreement or any of the terms or
              conditions of this Agreement, or if any governmental regulatory
              agency (e.g., SEC or DOT) requires the production or disclosure of
              this Agreement or its terms, such Carrier, at its option and after
              notifying the other Carrier, may produce or disclose the requested
              document or information.

       D.     If any financial institution requests or requires production or
              disclosure of this Agreement or its terms, ZK and UA may produce
              or disclose this Agreement provided the financial institution
              agrees to keep the disclosed material and information
              confidential.

       E.     Upon termination of this Agreement, all Confidential Information,
              including any copies thereof made by the receiving party, must be
              returned to the disclosing Carrier.

10.    FORCE MAJEURE
       Neither Carrier will be liable for delays or failure in performance under
       this Agreement caused by acts of God, war, strikes, labor disputes, work
       stoppage, fire, acts of government or any other cause, whether similar or
       dissimilar, which is beyond the control of that Carrier.

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11.    NATURE OF RELATIONSHIP BETWEEN ZK AND UA
       The relationship of the Carriers hereto is that of independent
       contractors. Nothing in this Agreement is intended or shall be construed
       to create or establish any partnership or joint venture relationship
       between the Carriers.

12.    TERMINATION FOR CAUSE
       A.     If either Carrier (the "Defaulting Party") becomes insolvent or is
              subject to liquidation, composition with creditors, reorganization
              or bankruptcy; if the other Carrier (the "Insecure Party") has
              evidence that the Defaulting Party is not paying its bills when
              due without just cause; if the Defaulting Party takes any step
              leading to its cessation as a going concern; or if the Defaulting
              Party either ceases or suspends operations for reasons other than
              Force Majeure, then the Insecure Party may immediately terminate
              this Agreement on notice to the Defaulting Party unless the
              Defaulting Party immediately gives adequate assurance of the
              future performance of this Agreement by establishing an
              irrevocable letter of credit issued by an bank acceptable to the
              Insecure Party, on terms and conditions acceptable to the Insecure
              Party, in an amount sufficient to cover all amounts potentially
              due from the Defaulting Party under this Agreement, which may be
              drawn upon by the Insecure Party if the Defaulting Party does not
              fulfill its obligations under this Agreement in a timely manner.

       B.     If either Carrier (the "Defaulting Party") fails to observe or
              perform any of its material obligations under this Agreement and
              if this failure continues for a period of thirty (30) days after
              written notice to the Defaulting Party thereof (except for any
              payments due, where the period to cure such non-payment will be
              five [5] days after notice) then, without prejudice to any other
              rights or remedies the other party may have, the other Carrier may
              terminate this Agreement as of the expiration date of this notice
              period.

13.    POST-TERMINATION RIGHTS
       Exercise by either Carrier of its right to terminate under any provision
       of this Agreement will not affect or impair its right to enforce its
       other rights or remedies under this Agreement. All obligations of each
       Carrier that have accrued before termination or that are of a continuing
       nature will survive termination, including, without limitation, any
       confidentiality and indemnity provisions.

14.    NON-WAIVER
       Any previous waiver, forbearance, or course of dealing will not affect
       the right of either Carrier to require strict performance of any
       provision of this Agreement.

15.    GENERAL INDEMNIFICATION
       The Carrier operating the Code Share flight or providing goods or
       services hereunder (the "Operating Carrier") agrees to indemnify and hold
       harmless the other Carrier (the "Marketing Carrier"), its directors,
       officers, employees, agents, subcontractors, and affiliates (each an
       "Indemnitee") from and against any and all liabilities, claims, demands,
       suits, damages, and losses, including, without limitation, all reasonable
       attorneys' fees, costs and expenses in connection therewith or incident
       thereto (including, without

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       limitation, attorneys' fees incurred by the Marketing Carrier in
       establishing its right to indemnification hereunder) (collectively
       referred to in this Article as "Claims") of third parties for death or
       personal injury to any person or persons whomsoever (including, without
       limitation, the Operating Carrier's employees, but excluding the
       Marketing Carrier's employees) and for loss of, damage to, destruction
       of, any property whatsoever (including, without limitation, any loss of
       use thereof), in any manner arising out of or in any way connected with
       goods or services furnished or to be furnished by the Operating Carrier
       under this Agreement, all whether or not arising in tort or occasioned in
       whole or in part by the negligence of the Marketing Carrier of any type
       or degree. The Operating Carrier shall, at the request of the Marketing
       Carrier, negotiate and defend any Claim brought against any Indemnitee or
       in which any Indemnitee is joined as a party defendant based upon any
       other matters for which the Operating Carrier has agreed to indemnify
       each Indemnitee as provided above. The Operating Carrier's obligations
       under this Article will survive the expiration or termination of this
       Agreement.

16.    INSURANCE

       A.     (1) UA shall procure and maintain (i) third party liability
              insurance for a minimum combined single limit (bodily
              injury/property damage) of U.S. $300,000,000 (three hundred
              million U.S. dollars) for each occurrence and (ii) Hull All Risks
              and Hull War Risks insurance covering its fleet. ZK shall be named
              as additional insured on UA's policies when UA is acting as the
              Operating Carrier (the "Operating Carrier"). UA, as Operating
              Carrier, shall waive their rights of subrogation against ZK. The
              insurance policies shall be endorsed with severability of interest
              clauses. UA shall furnish to ZK certificates of insurance
              evidencing the foregoing coverage prior to the commencement of
              this Agreement.

              (2) ZK shall procure and maintain (i) third party liability
              insurance for minimum combined single limit (bodily
              injury/property damage) of U.S. $300,000,000 (three hundred
              million U.S. dollars) for each occurrence and (ii) Hull All Risks
              and Hull War Risks insurance covering its fleet. UA shall be named
              as additional insured on ZKs policies when ZK is acting as the
              Operating Carrier. ZK, as Operating Carrier, shall waive their
              rights of subrogation against UA. The insurance policies shall be
              endorsed with severability of interest clauses. ZK shall furnish
              to UA certificates of insurance evidencing the foregoing coverage
              prior to the commencement of this Agreement.

       B.     ZK and UA shall each procure at its own cost employer's liability
              insurance and worker's compensation (or equivalent) against the
              liabilities of each respective Carrier to its employees in an
              amount not less than required by applicable law.

       C.     In the event of cancellation or adverse material change, the
              additional insured shall be provided not less than thirty (30)
              days prior written notice except that in the case of Hull War
              Risks insurance such period of notice shall be seven (7) days or
              such lesser period as may be available in accordance with the
              applicable insurance policy requirements.

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17.    EXCLUSION OF CONSEQUENTIAL DAMAGES
       NEITHER CARRIER WILL BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL OR
       CONSEQUENTIAL DAMAGES, INCLUDING LOST REVENUES, LOST PROFITS, OR LOST
       PROSPECTIVE ECONOMIC ADVANTAGE, WHETHER OR NOT FORESEEABLE AND WHETHER OR
       NOT BASED ON CONTRACT, TORT, WARRANTY CLAIMS OR OTHERWISE IN CONNECTION
       WITH THIS AGREEMENT, AND/OR THE PRODUCTS OR SERVICES PROVIDED HEREUNDER,
       AND EACH CARRIER HEREBY RELEASES AND WAIVES ANY CLAIMS AGAINST THE OTHER
       CARRIER REGARDING SUCH DAMAGES.

18.    NOTICES
       Any notices required to be sent under this Agreement will be sent by
       first class mail, postage prepaid, or any more expedient written means.

       If to ZK, notices will be addressed as follows:

                    Great Lakes Aviation, Ltd.
                    1022 Airport Parkway
                    Cheyenne, Wyoming 82001

                    Attn:  Doug Voss, President

       If to UA, notices will be addressed as follows:

                    United Air Lines, Inc.
                    P.O. Box 66100
                    Chicago, Illinois 60666
                    Attn:  Vice President - Alliances

       Notices sent via electronic means (e.g., telex, facsimile) will be
       effective immediately if received prior to 5:00 p.m. local time of the
       recipient. All other notices will be effective the first business day
       after receipt.

19.    GOVERNING LAW
       This Agreement and any dispute arising under or in connection with this
       Agreement, including any action in tort, will be governed and construed
       by the laws of the State of Illinois U.S.A., without regard to any
       conflict of laws principles which may direct the application of laws of
       any other jurisdiction.

20.    SEVERABILITY
       Each provision of this Agreement shall be valid and enforced to the
       furthest extent permitted by law. The invalidity or unenforceability of
       any provision of this Agreement shall not affect the validity or
       enforceability of any other provision.

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21.    ASSIGNMENT AND CHANGE OF OWNERSHIP
       A.     Neither Carrier may assign or otherwise transfer any of its rights
              or obligations under this Agreement to any third party without the
              prior written consent of the other.

       B.     Should for any reason whatsoever the ownership of either Carrier
              change such that another air carrier or affiliate of an air
              carrier acquires a ten percent (10%) or more ownership interest in
              either party, then within thirty (30) days of such occurrence
              either party may request renegotiation of this Agreement and,
              failing successful renegotiation within sixty (60) days of the
              request to renegotiate, either party may terminate this Agreement
              upon thirty (30) days notice to the other party.

22.    ENTIRE AGREEMENT
       This Agreement, the Transition Agreement and the various side letters
       issued pursuant to this Agreement, including any and all Attachments,
       constitute the entire agreement and understanding of the Carriers
       relating to the subject matter hereof, and supersedes all prior
       agreements, whether oral or written, express or implied, between the
       Carriers concerning the subject matter hereof. In the event that any
       terms herein conflict with the terms of any interline or other agreement
       between the Carriers, then the terms herein shall prevail, but shall not
       supplant any conflicting terms in the other agreement. This Agreement may
       be modified only by further written agreement signed by all of the
       Carriers hereto.

23.    EXISTING OBLIGATIONS
       UA represents and warrants that the terms of this Agreement do not
       violate any existing obligations or contracts of UA. ZK represents and
       warrants that the terms of this Agreement do not violate any existing
       obligations of ZK. Each Carrier shall defend, indemnify and hold the
       other harmless from and against any and all claims, demands or causes of
       action which are hereafter made or brought against it alleging any such
       violation.

24.    PERFORMANCE MEASURES                        (Attachment 6)
       ZK agrees to provide UA, monthly, with performance measures that UA will
       use to evaluate if ZK is providing service at a level that meets
       pre-determined standards, as set forth in Attachment 6. Any failure to
       maintain these standards shall immediately be brought to UA's attention
       along with corrective actions taken or a corrective action plan. Any
       non-compliance not promptly corrected to UA's satisfaction or repeated
       non-compliance shall be grounds for termination by UA without further
       liability, but with reservation of all other rights and remedies
       available to UA, provided, however, that ZK's failure to maintain
       performance standards shall not constitute grounds for termination if
       ZK's failure to perform is due to the relevant and material fault of UA.

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IN WITNESS WHEREOF, the Carriers hereto have by their duly authorized officers
executed this Agreement as of the dates set forth below.

    GREAT LAKES AVIATION, LTD.                     UNITED AIR LINES, INC.

By:  /s/ Doug G. Voss                    By:   /s/ Rono Dutta
   ----------------------------------       ------------------------------------

Name       Douglas G. Voss                           Rono Dutta

Title:     President and CEO                         President

Date: February 1, 2001                   Date: January 31, 2001

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                                  ATTACHMENT 1

                                  CODE SHARING

A.   City pairs displayed as UA*

          Subject to all necessary regulatory approvals, deployment of IATCI One
          Stop Check-In, and completion of necessary operational support
          arrangements, UA shall display its UA designation code on selected
          flights, operated by ZK, provided, however, that UA may remove, and ZK
          may stop carrying, the UA designation from any flights, upon 360 day's
          written notice:

                     ZK Operated Flights Between Chicago and

                              Chicago-Based Cities
                              Dubuque, IA
                              Muskegon, MI
                              Springfield, IL
                              Waterloo, IA
                              Iron Mountain, MI
                              Manistee, MI
                              Oshkosh, WI
                              Ottumwa, IA

                     ZK Operated Flights Between Denver and

                              Denver-Based Cities
                              Alamosa, CO
                              Alliance, NE
                              Amarillo, TX
                              Casper, WY
                              Chadron, NE
                              Cheyenne, WY
                              Cody, WY
                              Cortez, CO
                              Dickinson, ND
                              Dodge City, KS
                              Farmington, NM
                              Garden City, KS
                              Gillette, WY
                              Grand Island, NE
                              Gunnison, CO
                              Hayden, CO
                              Hays, KS

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                              Kearney, NE
                              Laramie, WY
                              Liberal, KS
                              Moab, AZ
                              McCook, NE
                              Norfolk, NE
                              North Platte, NE
                              Page, AZ
                              Phoenix, AZ
                              Pierre, SD
                              Pueblo, CO
                              Riverton, WY
                              Rock Springs, WY
                              Salina, KS
                              Santa Fe, NM
                              Scottsbluff, NE
                              Sheridan, WY
                              Telluride, CO
                              Vernal, UT
                              Williston, ND
                              Worland, WY
                              Yankton, SD

B.   Inventory Management

          The Carriers shall establish mutually agreed inventory management
          procedures for Code Share flights, in accordance with the guidelines
          outlined in Article 4 of this agreement ("Programs"), and including
          for manually managed inventory allocations the areas for cooperation
          outlined in Attachment 1A.

          TO BE COMPLETED BY January 31, 2002

          Action:

                ZK   Dick Fontaine    HDQSCZK    (307) 432-7020
                UA   Elisabeth Mach   HDQIMUA    (847) 700-6277

C.   Code Share Schedule Operations

The Carriers will:

     (1)  establish a dedicated flight number range for use by ZK and UA on Code
          Share flights.

     (2)  establish an automated transfer of flight schedule information via an
          industry standard SSIM which includes comment 10 and 50 records to
          identify the Code

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          Share relationships. A "custom SSIM" from ZK will be used in place of
          the OAG file to maintain ZK's schedule in the Apollo and Galileo
          computer reservation systems.

     (3)  establish a communications procedure to advise the other of passenger
          reaccommodation plans in the event of schedule changes involving a
          Code Share flight.

     TO BE COMPLETED BY January 31, 2002.

          Action:

                 ZK     Dick Fontaine    HDQSCZK     (307) 432-7020

                 UA     Tina Drzal       HDQRLUA     (847) 700-5020

D.   Interline Accounting

          The Carriers shall establish all necessary accounting procedures, in
          accordance with applicable IATA or ACH guidelines, including sampling
          methodology, to facilitate settlement of all UA/ZK interline
          transportation, including code share.

TO BE COMPLETED BY January 31, 2002.

          Action:

                 ZK     Teresa Henry     HDQRAZK     (307) 432-7040

                 UA     Bob Portschy     HDQANUA     (847) 700-1601

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                                  ATTACHMENT 1A

                        BUSINESS REQUIREMENTS CODE SHARE

TABLE OF CONTENTS

1.0  OVERVIEW

     1.1  Introduction

     1.2  Objective

2.0  REQUIREMENTS

     2.1  Availability

     2.2  Booking/Ticketing/CRS Fees

          2.2.1   Sell
          2.2.2   Disclaimer
          2.2.3   Group Handling
          2.2.4   Teletype (TTY)
          2.2.5   Customer Inquiries

     2.3  Inventory Maintenance

          2.3.1   Inventory Control
          2.3.2   Link Sells
          2.3.3   Waitlist

     2.4  Through Check In

     2.5  Schedule Maintenance

          2.5.1   Schedule Dissemination
          2.5.2   Schedule Change
          2.5.3   Passenger Reaccommodation
          2.5.4   Seat Reaccommodation

     2.6  Accounting Systems

     2.7  Frequent Flyer

3.0  Hardware

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1.0  OVERVIEW

          The purpose of this Attachment 1A is to provide a method that will
          allow UA's code to be reflected on certain ZK flights. Each Carrier
          shall perform this procedures in a fully automated manner, or manually
          until a fully automated method can be implemented.

2.0  REQUIREMENTS

     General Requirement

     Support code share for the city pairs as set forth on Attachment 1,
     paragraph A.

     2.1  Availability

          The Carrier shall provide the capability to display the service as an
          on-line connection using the designated Carrier's code (UA).

     2.2  Booking/Ticketing/CRS Fees

          2.2.1   Sell

                  The Carriers shall provide support for segment sell of the
                  on-line connection by line number from availability.

                  The Carriers shall provide support for the manual sell of the
                  connection using either the code share flight number or the
                  base flight number.

                  The Carriers shall provide for any fees associated with either
                  ticket handling fees or CRS fees related to transportation of
                  a passenger to be paid, by segment, by the Operating Carrier.
                  ZK and UA will establish a process to ensure that all such
                  fees are appropriately accounted for. The Operating Carrier
                  will be responsible for CRS fees at the level of participation
                  of the Marketing Carrier.

                  In this connection, the Marketing Carrier will be obligated to
                  provide the Operating Carrier only the CRS vendor's invoice
                  and the CRS vendor's generated microfiche or hard copy of
                  bookings for flights of Operating Carrier, and the Operating
                  Carrier must reimburse the Marketing Carrier based upon the
                  data reflected in those documents without adjustment.

          2.2.2   Disclaimer

                  The Carriers shall provide for a disclaimer to accompany a
                  sell of a shared-code flight identifying the Carrier operating
                  the flight. The

                                       15

<PAGE>

             disclaimer must be distributed to CRS's and to schedule
             dissemination services such as the Official Airline Guide (OAG).

     2.2.3   Group Handling

             Groups will be booked through each Carrier's group desk.

     2.2.4   Teletype (TTY)

             Teletype processing will be handled for UA or ZK designated flights
             as it is currently handled today.
             The information will be updated within the PNR of the respective
             system automatically and will be passed with the PNR on the
             exchange of PNRs.

     2.2.5   Customer Inquiries

             Procedures will be established through the reservations groups to
             be able to identify where a PNR exists and be able to direct the
             customer appropriately.

2.3  Inventory Maintenance

     2.3.1   Inventory Control

             The operating Carrier will develop a method for inventory control
             on each Code Share flight to/from the designated cities and will
             maintain control of that inventory. The designated Carrier will
             create a pseudo flight with the appropriate inventory. The yield
             management groups of both Carriers will agree on the following:

                  - A method of managing inventory allocations on shared-code
                    flights.

                  - Actual allocation of agreed number of seats by cabin.

                  - Close off and transfer of PNRs, at a minimum 24 hours prior
                    to departure of shared-code flights.

                  - For manually managed inventory allocations, exchange of
                    industry standard PNL's, at a maximum 72 hours prior to
                    departure, and ADL's at a mutually agreed time prior to
                    departure, of shared code flights.

                  - Class of service and class of service equivalency

                                       16

<PAGE>

                 - A communications procedure to allow ad hoc inventory changes
                   and to ensure that unused inventory is released or
                   transferred.

     2.3.2 Link Sells

           Allow a shared-code flight to be sold from an availability display
           provided to another Carrier.

     2.3.3 Waitlist

           Waitlists will be open at start up of the Code Share arrangement.

2.4  Through Check In

     Provide the capability to through-check customers via the use of IATCI
     standards.

2.5  Schedule Maintenance

     2.5.1 Schedule Dissemination

           Each Carrier will establish an automated transfer of flight schedule
           information via an industry standard SSIM which includes comment 10
           and 50 records to identify the Code Share relationships. A "custom
           SSIM" from ZK will be used in place of the OAG file to maintain ZK's
           schedule in the Apollo and Galileo computer reservation systems.

     2.5.2 Passenger Reaccommodation

           Reaccommodations will be worked through close coordination between
           the reservations groups of the two Carriers.

     2.5.3 Flight Information

           ZK and UA will evaluate procedures for exchanging and updating FLIFO
           information in each other's systems. Procedures and responsibility
           will be determined and mutually agreed by the Carriers.

2.6  Accounting Systems

     Accounting based on billing is currently handled on a manual basis for bank
     Air Lines flights and does not create any new issues. Any special prorates
     must be communicated to accounting to ensure proper billing.

                                       17

<PAGE>

     2.7   Frequent Flyer

           Procedures for providing automated accrual and redemption will be
           established by respective Frequent Flyer organizations.

3.0  Hardware

           Each Carrier will provide and pay for installation and maintenance of
           computer equipment necessary for the other to support Code Share
           operations. This equipment may include, but is not limited to
           check-in terminals, boarding pass printers and bag tag printers. Any
           monthly charges associated with such equipment will be paid by the
           Carrier supplying said equipment.

           Upon termination of Code Share operations, for any reason, the
           Carriers will return any equipment owned by the other party.

                                       18

<PAGE>

                                  ATTACHMENT 2

                         CODE SHARE EMERGENCY PROCEDURES

In order to properly prepare and plan coordinated communications efforts between
the Carriers in the event of an emergency, as defined below, involving a Code
Share flight, both Carriers will (i) exchange and update the appropriate
telephone numbers and SITA addresses of the operating Carrier to which the code
sharing Carrier may refer customer/relative inquiries in the event of an
emergency and (ii) discuss any other necessary coordinated emergency response
procedures. Although each situation must be evaluated on its own merit, common
sense must prevail as a guide for all parties to follow.

Definitions:

-Emergency

Any occurrence involving a Code Share flight that results in injury or death, or
has the potential for injury or death to any person or the loss or damage or the
potential for loss or damage to private, public, or Carrier property.

-Aircraft Accident

Any occurrence associated with the operation of an aircraft, which takes place
between the time the captain has released the parking brake for pushback or taxi
and has set the parking brake and all checklists are completed, in which any
person who has boarded the aircraft with the intention of flight suffers death
or serious injury or in which an aircraft receives substantial damage.

-Hijacking (Air Piracy)

Any seizure or exercise of control by force or violence, or threat of violence,
and with wrongful intent of an aircraft in air commerce.

-Red Alert

The classification for a situation where a major problem exists that may result
in an accident as defined above. Examples include a landing gear failure to
extend, fire in flight, or other aircraft damage that will likely require
outside agencies such as police, fire, ambulances, and physicians to respond.

Both Carriers agree to comply with the relevant requirements of government
agencies having jurisdiction in respect of an Emergency, Aircraft Accident,
Hijacking or Red Alert.

Appropriate UAL telephone numbers in the event of an emergency as described
above:

     UAL Shift Manager (24 Hours)
     847 700-6295                      (Phone)
     847 700-2005                      (FAX)
     HDQOPUA                           (SITA Address)

Appropriate ZK telephone numbers in the event of an emergency as described
above:

     ZK Shift Manager   (24 Hours)
     307-432-7222       (Phone)
     307-432-7221       (FAX)
     HDQOOZK            (SITA Address)

                                       19

<PAGE>

Any change to the above referenced phone numbers or contacts is to be
communicated to the above referenced SITA addresses with a request for a
confirming telex back to the originator to acknowledge receipt.

B.  EMERGENCY PLAN

    (1)  The Carriers mutually agree to subscribe to the IATA Standards and
         Recommended Practices for the Assistance of Survivors and Families of
         Passengers in the Aftermath of an Aircraft Accident or Incident.

    (2)  In addition to the aforementioned procedures, the Carriers will meet
         and endeavor to mutually agree on a detailed emergency plan.

TO BE COMPLETED BY January 31, 2002

    Action:

           ZK  Dick Nelson    HDQSCZK       (307) 432-7210
           UA  Jim Konz       HDQCSUA       (847) 700-5133

                                       20

<PAGE>

                                  ATTACHMENT 3

                       PRORATES AND FREQUENT FLYER PROGRAM

A.     Prorates

       ZK and UA shall provide access to each other's system by maintaining the
       current standard prorate methodology (straight rate proration) to support
       the overall program and to stimulate incremental traffic from UA to ZK,
       and ZK to UA.

       TO BE COMPLETED FOR IMPLEMENTATION, AS MUTUALLY AGREED, EFFECTIVE January
       31, 2002

       Action:

                    ZK       Teresa Henry       HDQRAZK        (307) 432-7040

                    UA       Yvonne Fox         HDQNCUA        (847) 700-4963

B.     Frequent Flyer Program

       ZK and UA shall implement mutually beneficial programs to enhance ZK/UA
       passenger loyalty including, as follows:

       .      Handling of Frequent Flyer accrual information on ZK and UA
              flights to provide consistency.

       .      Accrual and redemption levels to be charged by each Carrier for
              travel by its Frequent Flyer members on code share sectors
              operated by the other.

       IMPLEMENTATION PLAN, AS APPROPRIATE, TO BE COMPLETED FOR IMPLEMENTATION
       ON January 31, 2002.

       Action:

                    ZK        Dick Fontaine     HDQSCZK        (307) 432-7020
                    UA        Lou Brigham       HDQPRUA        (847) 700-7692

                                       21

<PAGE>

                                  ATTACHMENT 4

                             JOINT SERVICE FEATURES

A.     Automated One Stop Check-In

       When the UA/ZK codeshare arrangement becomes operational, both Carriers
       shall have developed, tested, and implemented fully automated One Stop
       Check-In. Services rendered shall include:

                        -    Seat Assignments
                        -    Boarding Cards
                        -    Frequent Flyer Credit
                        -    Baggage Check to final destination

       for up to three segments under each Carrier's designator code, for a
       maximum of six (6) segments (five connecting points). Segments under the
       "UA" designator code may include flights operated by UA Express Carriers.

       TO BE IMPLEMENTED BY January 31, 2002 FOR THE CITY PAIRS AS SET FORTH ON
       ATTACHMENT 1, PARAGRAPH A AND B OF THE CODE SHARE AND REGULATORY
       COOPERATION AGREEMENT.

       Action:

                    ZK       Jim Frazier        HDQSCZK        (307) 482-7270
                    UA       Brett Anderson     DENKAUA        (303) 779-7081

B.     Improved Connection Scheduling

       (1)    Each Carrier shall complete a review of all practical ZK/UA
              schedule improvement possibilities at all common gateways.

       (2)    Each Carrier shall establish a plan for ongoing, regularly
              scheduled reviews to optimize future schedule changes by either
              party.

       TO BE COMPLETED BY January 31, 2002.

       Action:

                    ZK       Dick Fontaine      HDQSCZK        (307) 432-7020
                    UA       Tim Drzal          HDQASUA        (847) 700-5020

                                       22

<PAGE>

C.     Inflight Service Coordination

       The Carriers shall establish a forum to exchange ideas and suggestions on
       Inflight Services to help provide consistency for the customer.

       TO BE COMPLETED BY January 31, 2002, FOR IMPLEMENTATION by the first day
       of operation of the codeshare - to be determined.

       Action:

                    ZK       Dick Nelson        HDQSCZK        (307) 432-7210
                    UA       Arlene Johnson     HDQSWUA        (847) 700-3592

D.     Seamless Transfer Service

       The Carriers shall evaluate and develop proactive procedures and identify
       facilities to be used to ensure expeditious check-in and transfer of
       passengers and baggage between the respective services at all common
       hubs. Areas for review and coordination include:

       (1)    Support for connecting passengers and baggage

       (2)    Information and directional signage to assist customers

       (3)    Security procedures as governmentally required

       TO BE COMPLETED FOR IMPLEMENTATION BEGINNING ON January 31, 2002.

       Action:

                    ZK       Jim Frazier        HDQSCZK        (307) 432-7270
                    UA       James Gabriel      HDQCSUA        (847) 700-5393

E.     Group Procedures

       Groups shall be booked through each Carrier's group desk.

       Contacts:

                    ZK       Pam Flynn          HDQSCZK        (307) 432-7295
                    UA       Pat Snelling       HDQRRUA        (313) 234-6937

                                       23

<PAGE>

F.     Air Cargo Service

       ZK and UA shall review and implement, as agreed, programs including
       prorates, booking and inventory capabilities, and joint trade show
       participation.

                    ZK       Brent Skillman     HDQSCZK        (612) 889-9329
                    UA       Michael Stacy      HDQSAUA        (847) 700-5637

       TO BE COMPLETED FOR IMPLEMENTATION BEGINNING ON January 31, 2002

                                       24

<PAGE>

                                  ATTACHMENT 5

                             DISTRIBUTION/AUTOMATION

A.     Display Improvement

       To the extent permitted by applicable law and regulations, UA and ZK
       connections shall receive preference in the Carrier specific display
       option or direct access programs either UA or ZK has with any other
       computer reservation systems used by travel agents, corporate accounts,
       or any non-airline staff for the purpose of making airline reservations,
       or internal displays.

       TO BE COMPLETED BY January 31, 2002.

       Action:

                    ZK       Pam Flynn          HDQSCZK        (307) 432-7295
                    UA       George Tyms        HDQIMUA        (847) 700-5667

B.     Quality Control

       ZK and UA shall each use its best, commercially reasonable efforts to
       ensure that the other party's flights, connect points, fares, and rules
       both on-line and between ZKJUA are included in each Carrier's respective
       host and affiliated CRS system data base and are eligible for display
       subject to system constraints and applicable laws and regulations.

       TO BE COMPLETED BY January 31, 2002.

       Action:

                    ZK       Pam Flynn          HDQSCZK        (307) 432-7295
                    UA       George Tyms        HDQIMUA        (847) 700-5667

C.     Preferential Selling/Reservation Sales

       ZK and UA shall implement programs and incentives to motivate key ZK and
       UA reservations to reciprocally sell their code share products, on a
       "second to on-line" basis.

       TO BE COMPLETED FOR IMPLEMENTATION BY January 31, 2002.

       Action:

                    ZK       Dick Fontaine      HDQSCZK        (307) 432-7020
                    UA       Teri Hartwig       HDQRZUA        (847) 700-5942

                                       25

<PAGE>

                                  ATTACHMENT 6

                              PERFORMANCE MEASURES

ZK shall provide monthly results of its performance, system-wide, to UA, and
shall meet the minimum performance standards as follows, or meet the performance
standards as reported by UA for Denver for the same period and operational
categories, whichever is lower:

..      Flight Schedule Departure Completion (excluding weather and ATC):  98.0%
..      On-time departures as scheduled (zero)                             56.0%

ZK agrees to ensure that this information is accumulated and maintained in such
a manner that it can be readily audited for accuracy by representatives of UA.
UA, or its representatives, shall have the right to audit such information at
any reasonable time at the location where the records are maintained by ZK.

       Action:

                    ZK       Dick Nelson        HDQSCZK        (307) 432-7210
                    UA       Dennis Berry       HDQNCUA        (847) 700-9378

                                       26<PAGE>

                                                                   EXHIBIT 10.24

                              CODE SHARE AGREEMENT

This Code Share Agreement is made as of May 3, 2001, by and between Frontier
Airlines, Inc. ("Frontier"), a Colorado corporation and Great Lakes Aviation,
Ltd. ("Great Lakes"), an Iowa corporation.

A.   Frontier and Great Lakes are each operating, certificated air carriers
providing air transportation services in their respective areas of operation.

B.   Frontier and Great Lakes desire to engage in joint marketing activities
designed to increase the flow of air passenger traffic on aircraft operated by
both parties.

C.   Frontier and Great Lakes desire to cooperate in the coordination of
schedules by allowing Great Lakes to market its flight operations under the
"F9*" designator.

     NOW, THEREFORE, in consideration of the premises and the mutual promises
herein contained, Frontier and Great Lakes hereby agree as follows:

Section 1.  Definitions

(1) Code Share Service. "Code Share Service" means the holding out and marketing
to the public of F9* designated, single carrier passenger transportation and
cargo on a city pair route where the air transportation is provided via
connecting flights operated by both Great Lakes and Frontier, and where the F9*
designator is applied to the flight(s) operated by Great Lakes.

(2) Operating Carrier. "Operating Carrier" means the party having operational
control of an aircraft used for a given segment of Code Share Service.

(3) Ticketing Carrier. "Ticketing Carrier" means a carrier whose traffic
documents are used to issue a ticket.

(4) Ticket Taxes. "Ticket Taxes" means any transactional taxes or passenger
facility charges, including, without limitation, international taxes and
charges, sales taxes, segment taxes and fees, use taxes, stamp taxes, excise
taxes, value added taxes, gross receipts taxes, departure taxes, surcharges and
travel taxes, and all related charges, fees, licenses or assessments (and any
interest or penalty thereon) imposed on passengers (or which air carriers or
their agents are required to collect from passengers) by any authority in any
country, or political subdivision thereof or public authority operating therein
(including, without limitation any national, federal, state, provincial,
territorial, local, municipal, port or airport authority) or which are levied
upon passengers by operation of applicable law or industry standard. Ticket
Taxes together with the taxes referred to elsewhere in

<PAGE>

Section 25 hereof are collectively referred to as "Taxes."

(5) Implementation Date. The "Implementation Date" means July 9, 2001.

(6) Code Share Passenger. A "Code Share Passenger" is a passenger whose air
transportation is provided via connecting flights, operated by both Great Lakes
Aviation and Frontier Airlines and where the F9* designator is applied to the
flight operated by Great Lakes Aviation.

Section 2.  Code Share Service

(1) Code Share Service. To the extent permitted by applicable laws, and as
mutually agreed, Great Lakes operated flights that connect with Frontier
operated flights, will be marketed under Frontier's F9* designator code. Great
Lakes agrees not to enter into any additional code share agreements for markets
served by Frontier with Northwest Airlines, Continental Airlines, Delta Airlines
or American Airlines. Frontier agrees to not enter into any additional code
share agreements for markets served by Great Lakes that are listed in Exhibit A.
Exhibit A hereto sets forth the flight segments operated by Great Lakes that,
when connecting with a flight operated by Frontier will utilize the designator
code F9* ("Code Share Flights"). The parties shall meet together as often as is
mutually agreed during the period this Agreement is in effect to discuss the
appropriateness of expanding or contracting the list of city pairs on Exhibit A.
Flights covering an origin and destination market that is created by an F9* Code
Share Flight connecting to a Frontier flight operated by Frontier are
hereinafter referred to as "Through Flights." Except as expressly set forth
herein, neither party shall have any obligation to extend Frontier or Great
Lakes flights to other routes or to maintain operations on any routes and no
such obligation can be created by any oral statements or representations or
course of dealing by a party, but only by an express written agreement.

(2) Procedures Manual. As a guide to the implementation of this Agreement, the
parties will prepare a Procedures Manual, which may be modified from time to
time, containing detailed procedures regarding the operation of this Agreement.
The parties agree to complete and agree on the initial Procedures Manual no
later than 45 days before the first date that a Codeshare Flight is conducted
(the "Implementation Date"), as defined in this Agreement.

(3) Conditions of Carriage. The Terms and Conditions of Contract of Carriage of
Frontier Airlines shall govern the transportation of Code Share Passengers.

      (a) The parties will use existing IATA procedures when handling and
settling claims made by customers in connection with Through Flights.

Section 3.  Confidential Information

(1) Except as set forth below, and except in any proceeding to enforce any of
the provisions of this Agreement, neither Frontier nor

<PAGE>

Great Lakes will, without prior written consent of the other, use, publicize or
disclose to any third party, either directly or indirectly, any of the following
(hereinafter "Confidential Information"):

       (a) this Agreement or its terms or conditions

       (b) Any confidential or proprietary information or data, either oral or
written, received from and designated as such by the disclosing carrier.

(2) If either carrier is served with a subpoena or other legal process requiring
the production or disclosure of any Confidential Information, then that carrier,
before complying, will immediately notify the non-disclosing carrier so the
non-disclosing carrier shall have a reasonable period of time to intervene and
contest disclosure or production if the non-disclosing carrier so chooses. If a
governmental authority requests either Frontier or Great Lakes to produce or
disclose to the authority this Agreement or any of the terms or conditions of
this Agreement, or if any governmental regulatory agency (e.g., Securities and
Exchange Commission or Department of Transportation) requires the production or
disclosure of this Agreement or its terms, such carrier may produce or disclose
the requested document or information.

(3) If any financial institution requests or requires production or disclosure
of this Agreement or its terms or conditions, in connection with a current or
proposed financing, Frontier or Great Lakes may produce or disclose this
Agreement provided the financial institution agrees to keep the disclosed
material and information confidential.

Section 4.  Code Sharing License

(1) Grant of License. Subject to the terms and conditions of this Agreement,
Frontier hereby grants to Great Lakes a nonexclusive, nontransferable, revocable
license to use the F9* designator code on all its flights operated as Code Share
Flights. Frontier agrees to not grant a license to use its F9* designation code
or any other code or service marks to any other carrier for use in Code Share
Service in markets set forth in Exhibit A, hereto, as may be supplemented or
amended from time to time.

(2) Service Marks. Great Lakes shall have a nonexclusive, nontransferable,
revocable license to use the Frontier Service Marks (as defined below) in its
marketing programs for the purpose of promoting F9* Flights. All advertising
programs using Frontier Service Marks shall be subject to Frontier's prior
approval. In general, Great Lakes' use of the Frontier Service Marks shall do no
more than identify the code share relationship between Great Lakes and Frontier
and advertise that schedules are coordinated to provide convenient connections.
Any marketing program, advertising brochures, schedules, signs or information
disseminated to the public or intended to be disseminated to the public
("Advertising Material") shall reflect that Great Lakes and Frontier are
operated

<PAGE>

separately and shall comply with any DOT policy on airline designator code
sharing.

(3) Great Lakes is specifically prohibited from using any of the Frontier
Service Marks on its aircraft or other equipment, on its stationary, or
elsewhere unless Great Lakes has received prior specific authorization in
writing from Frontier. Great Lakes hereby acknowledges Frontier's exclusive
ownership of the Frontier Service Marks and agrees that it will not do anything
that would infringe, abridge or adversely affect, impair or reduce the value or
validity of the Frontier Service Marks. In no event shall Great Lakes allow the
use of any Frontier Service Marks in marketing, selling, promoting or otherwise
identifying or referencing any flight which is not an F9* Flight. Frontier
hereby grants to Great Lakes a nonexclusive, nontransferable, revocable license
to use the name Frontier and its service marks in Great Lakes marketing
programs, for the purpose of promoting the F9* Flights. As used herein the term
"Service Marks" shall include, without limitation the Frontier designator code,
various trademarks, service marks and logos.

Section 5.  Sales and Marketing Programs

The parties will work to develop mutually agreeable joint sales and marketing
programs to help promote the code share relationship and increase revenues from
same. The parties will conduct quarterly joint sales and marketing meetings to
discuss possible sales and marketing programs and strategies.

Section 6. Schedules and Flight Display

(1) Schedule Filing. Frontier and Great Lakes shall coordinate the filing of
schedules with the Official Airline Guide ("OAG") (and any other airline guide
or schedule as mutually agreed) for Through Flights. To facilitate the schedule
filing process, Frontier and Great Lakes shall supply to each other the
necessary detail in writing in sufficient time to meet applicable filing
deadlines, but in no case less than 45 calendar days prior to the effective date
of the schedule (or notice as far in advance as possible if 45 days is
impracticable). A separate set of consecutive Frontier flight numbers will be
assigned to Great Lakes for F9* designated flights operated by Great Lakes.

(2) Flight Display. All Through Flights will be included in the availability and
fare displays of all computerized reservations systems in which Frontier and
Great Lakes participate, the OAG (to the extent agreed upon) and Frontier and
Great Lakes internal reservation systems under the F9* designator code. Frontier
and Great Lakes will take the appropriate measures necessary to ensure the
display of Through Flights in accordance with the preceding sentence.

     (a) Frontier and Great Lakes will disclose and identify the Great Lakes
flights utilizing the F9* designator code to the public as actually being
flights of and operated by Great Lakes, in at least the following ways:

<PAGE>

           (i)   a symbol will be used in timetables and computer reservation
systems indicating that F9* Flights are actually operated by Great Lakes;

           (ii)  to the extent reasonable, messages on airport flight
information displays will identify the operator of flights shown as F9* Flights;

           (iii) Frontier and Great Lakes advertising concerning F9* Flights and
Frontier and Great Lakes reservationists will disclose the operator of each
flight; and,

           (iv)  in any other manner prescribed by law.

(3) Flight Information. Great Lakes shall use reasonable efforts to keep current
flight following information for F9* designated flights operated by Great Lakes
for display in the Frontier reservation system. This information shall be
updated regularly by Great Lakes.

(4) Changes of Service. Each party shall give the other party 60 days advance
written notice (or notice as far in advance as possible if 60 days is
impracticable) of any intended material changes to (a) its operating
specifications, or (b) to the manner of conducting its business or the nature of
its product as it relates to its operations at Denver, Minneapolis/St. Paul, or
Phoenix. In the event any such change has an adverse material change to the
value or risk to the other party of this Code Sharing Agreement in the other
party's judgement, the other party shall be entitled to terminate this agreement
if the change is implemented.

Section 7.  Pricing and Capacity Control of Code Shared Segments

(1) Pricing. Frontier and Great Lakes shall jointly establish and set fares for
Through Flights. Frontier shall have no authority to establish or set fares for
Great Lakes Flights. If no fare is set for a Through Flight, the fare for such
Through Flight will be the sum of each carrier's segment fares.

(2) Tariffs. For F9* Code Share Service, Frontier and Great Lakes shall develop
jointly (consistent with each Carrier's other preexisting code share
relationships) those conditions of carriage and tariff rules that need to be
uniform in order for the Code Share Service to be provided in a seamless manner.
Such rules governing the air transportation provided as part of a F9* Code Share
Service shall be available for public inspection at Frontier's and Great Lakes'
corporate offices, at each airport ticket office, and at each city ticket office
maintained and operated by Frontier or Great Lakes in the manner required by DOT
regulations.

(3) Each Carrier will have access to the other Carrier's inventory through an
automated computerized interface which both parties will maintain throughout the
term of this Agreement to expedite the sale of inventory on the Code Share
Flights.

<PAGE>

(4) The parties will map inventory classes of Frontier flights to inventory
classes of Great Lakes flights on the Code Share Flights by mutual agreement.
The parties will endeavor to map the average coupon value of Frontier's
inventory classes to comparable classes of Great Lakes to provide
nondiscriminatory access for bookings made by each carrier for passengers
yielding comparable revenue values; it being understood, however, that the
Operating Carrier retains ultimate control over the opening, closing, and other
management of seat inventory availability on Code Share Flights.

(5) Each carrier will be able to book Code Share Passengers up to the same
maximum seat inventory per booking class (including authorized overbooking)
available to the other carrier for a Code Share Flight, provided that such seats
may be available for sale on an equal basis under other designator code(s).

(6) Frontier and Great Lakes will each assign one or more individuals to serve
as inventory control coordinators, who will, to the extent permitted by
applicable law, exchange information routinely and conference as necessary to
assure that reasonable seat inventory on Code Share Flights is made available.

Section 8.  Quality of Service

Great Lakes shall perform its service in a timely, expert and quality manner.
Great Lakes shall maintain its aircraft in an airworthy, clean, attractive and
comfortable condition and will maintain a completion factor of at least 97%
(excluding cancellations caused by air traffic control, weather, or force
majeure) in its F9* operations or meet the performance standards as reported by
Frontier for the same period, whichever is lower. Great Lakes will, in
conducting F9* Flight operations, employ prudent safety and loss prevention
policies.

Section 9.  Control of F9* Flights

Great Lakes shall have sole responsibility for and control over, and Frontier
shall have no responsibility for, control over or obligations or duties with
respect to, each and every aspect of Great Lakes operations including, without
limitation, scheduling (except as provided in Section 6 hereof); pricing (except
as provided in Section 7 hereof); planning of flight itineraries and routings;
reservations; reservations control/yield management; dispatch; fueling; weight
and balance; flight release; maintenance; and flight operations and compliance
with applicable rules and regulations.

Section 10.  Aircraft and Crews

Frontier and Great Lakes will provide the scheduled air service that is part of
F9* Code Share Service in full compliance with FAA regulations applicable to
scheduled air service. Flights operated by Frontier shall be operated by its
aircraft and crews and Flights operated by Great Lakes shall be operated by its
aircraft and crews. Each party may utilize "wet" leases if mutually agreed

<PAGE>

upon prior to operation of the aircraft on flights using the F9* Code Share
designation.

Section 11.  Ground Support for Code Share Services

(1) Great Lakes Cities. Great Lakes will provide to passengers traveling on
Great Lakes flights using F9* Code Share Service passenger check-in at each of
the stations specified in Exhibit A. To the extent reasonably feasible,
passenger check-in and handling procedures will be provided in accordance with
mutually agreed operating procedures. Frontier and Great Lakes will jointly
develop a method of providing Great Lakes' stations with assistance in check-in
and ticketing of Code Share Passengers. Frontier will provide to Great Lakes, at
no cost to Great Lakes, the necessary familiarization training in Frontier's
procedures. Great Lakes shall arrange for Frontier identification to be
prominently displayed at check-in counters and gate areas as appropriate at each
of Great Lakes' stations where F9* designated Great Lakes flights are operated.
Such signage shall be at least equal in prominence to that of any other airline
graphics, excluding Great Lakes, displayed at such Great Lakes stations.
Frontier, at its cost will develop and provide standardized signage material
subject to Great Lakes approval. Such signage may be modified as necessary to
conform to local station requirements for display at all Great Lakes stations
described in Exhibit A. The parties agree to cooperate to accomplish the
objectives set forth in this paragraph as quickly as is reasonably feasible;
provided, however, that completion of the obligations set forth in this
paragraph are not conditions precedent to the effective date of this Agreement
and the other obligations of the parties hereunder.

(2) All Other Cities. The parties intend to work to establish a convenient
connection for passengers connecting from an F9* flight to a flight operated by
Frontier (or vice versa) while traveling on a Through Flight. Frontier and Great
Lakes will cooperate to maximize the convenience of passengers who are
connecting from a Great Lakes flight segment (or vice versa) on Through Flights.
Each party will provide the other with the airport operational assistance that
is required to assure schedule compatibility for Through Flights.

(3) Freight. Frontier and Great Lakes will accept air freight and small package
shipments for F9* Code Share Service to and from points served by Frontier and
Great Lakes Flights. Documentation and handling procedures for such freight
shall be consistent with Frontier, Great Lakes and standard industry procedures.

(4) Government Contracts.

      (a) Frontier and Great Lakes shall each independently contract with the
U.S. Postal Service for carriage of mail over their respective route networks.
The use of the F9* designator for F9* Code Share Service does not extend to the
system mail

<PAGE>

contract rates between each carrier and the U.S. Postal Service.

     (b) Each airline shall independently contract with the FAA, DOT or other
governmental agencies with respect to all landing, departure and en route slots
or other operational controls. This Agreement will not affect any rights either
airline has in current or future slots.

(5) Flight Irregularities. In the event of any flight cancellation or other
schedule irregularity, involuntary rerouting or denied boarding by the operating
carrier with respect to any segment of Code Share Service, the operating carrier
shall ensure that all passengers shall be handled in accordance with the same
policies and procedures to avoid any discrimination against a Code Share
Passenger. It is the intent that the offending carrier shall pay the costs of
such passenger accommodation.

     (a) at its own cost and expense, accommodate and/or pay denied boarding
compensation or otherwise compensate Code Share Passengers, in accordance with
the provisions of the Procedures Manual; and

     (b) reimburse the non-offending carrier, in accordance with the Procedures
Manual, for all reasonable costs incurred in connection with the compensation
and/or accommodation of Code Share Passengers as a result of a schedule
irregularity, involuntary rerouting or denied boarding as contemplated by this
Section. For the purposes of this paragraph only, "non-offending carrier" is
defined as the operating carrier who delivers a Code Share Passenger to the
connecting point at the agreed minimum connect time prior to the scheduled
departure time of the other code share partner.

(6) Baggage Claims. Baggage handling and settlement of baggage handling claims
shall be in accordance with existing tariffs and the Trade Practice Manual of
the Air Transport Association or the IATA Resolutions and Recommended Practices
Manual, whichever applies.

(7) Emergency Situations. Frontier or Great Lakes as the case may be shall
promptly notify the other carrier of all irregularities involving one of its
flights which result in any damage to persons or property as soon as such
information is available and shall furnish to the other as much detail as
practicable. For purposes of this section, notification shall be made as
follows:

     To Frontier Dispatch
     To Great Lakes Dispatch

     (a) Public Relations. In the event of any irregularity in Great Lakes
Flight operations, including, without limitation, any event causing damage to
persons or property, Great Lakes shall identify itself as being operated
independently of Frontier and as being solely responsible for its operations.
Great Lakes may state that it holds a code sharing license from Frontier and
that it obtains certain services from Frontier if third parties inquire as to
such relationship.

<PAGE>

Section 12.  Audit

Each Carrier shall have the right, at its own cost, to inspect, review, and
observe the other carriers operations of Through Flights, and/or to conduct a
full safety and/or service audit of the other carriers operations, manuals and
procedures reasonably related to Through Flights, at such intervals as each
carrier shall reasonably request. In the exercise of such right, neither carrier
shall undertake any responsibility for the performance of the others operations.
Each carrier shall coordinate its safety and service audits with the other so as
to avoid disruptions of the other carriers operations. Any safety audit may
include, without limitation, maintenance and operation procedures, crew
planning, reservations, passenger and baggage handling, customer service,
personnel records, spare parts, inventory records, training records and manuals,
flight training and operational records. If a party desires to establish the
current economic viability of the other party and its financial capability to
perform under this agreement, it may, at its sole expense, request that the
independent public accountant of the other carrier perform a review, but not an
audit, of that carriers financial position and receive a report thereon.

Section 13.  Reporting Obligations

(1)  Operations. Frontier and Great Lakes shall provide each other with monthly
written reports containing the following data for Through Flights:

     (a)  the total number of scheduled and actual flights performed and
cancellations by categories for the month, by market;

     (b)  completion and on-time performance data by system and market. In
addition, designated representatives of each carrier will meet monthly to review
such reports and initiate action to improve performance as necessary.

(2)  Notice of Complaints. Each carrier shall furnish monthly to the other
carrier a summary of complaints, notices of violation, requests to cease
activity or similar correspondence which reasonably relate to Through Flights
and which are received by the air carrier from passengers, any government
authority, or other parties. Each carrier shall comply with the other carriers
reasonable requests for actual copies of any such documents.

(3)  Correspondence from Government Authorities. Each Carrier shall immediately
provide the other any copies of any correspondence received from any government
authority, which references (a) any alleged noncompliance with rules or
regulations affecting air transportation, or (b) any investigation performed or
proposed by any government authority, including without limitation, any
communication issued by a government authority concerning the airworthiness of
aircraft, the compliance of the carrier's personnel with required operational or
training procedures or any other matter relating to the safe operation of the
carrier's aircraft.

<PAGE>

Section 14.  CRS Charges

Each carrier shall be responsible for its' own computer reservation systems
costs.

Section 15.  Prorate Agreement

(1)  Frontier and Great Lakes agree to divide revenues and otherwise prorate
fares as set forth below:

     (a)  Prorates. The parties agree to utilize straight rate proration by
segment as defined in the Passenger Proration Rules Manual subject to the
following condition:

          (i)  Through fares for prorate will be determined by using published
"high *" fares. Such fares will be mutually agreed to, and set forth in
Attachment B hereto. Great Lakes minimum under such prorate however, in no event
shall be less than $*.

     (b)  Applicable Fares. For fare verification purposes, the applicable
published fare is that filed with the U.S. DOT or shown in Air Tariff or Airline
Passenger Tariff in PIPPS (Passenger Interline Prorate System) in effect on the
date the passenger's ticket is issued.

          (i)  Fare Types. All F9* published and unpublished fares, F9* Visit
USA (VUSA) fares, F9* Senior Discount fares, and F9* bereavement fares.

     (c)  Place of Issue. Worldwide.

     (d)  Routing. The amount to be prorated must be between points in the U.S.
and travel must be via Frontier and Great Lakes.

     (e)  Interline Service Charge. All flight coupons billed under this
agreement will be subject to the interline service charge as outlined in the ACH
Manual of Procedure.

     (f)  Reservations for Travel. For fares within TC1, all segments must be
booked as per the first letter of the applicable fare basis code except as
otherwise agreed between the Carriers Pricing/Yield Management groups.

     (g)  Applicable Flights. Travel as specified in Exhibit A between cities
served by Great Lakes on the one hand and cities served by Frontier on the other
("Through Flights") is permitted as defined in this Agreement.

     (h)  Rule Waivers. The billing carrier shall recognize rule waivers granted
by the other carrier and its agents with respect to any provisions that may
apply to any fare covered under this Agreement. Waiver of booking classes is not
permitted.

     (i)  Situations not covered. The provisions of the ACH Passenger Proration
Rules Manual as applicable, will govern those situations not specifically
addressed herein.

* Confidential material omitted and filed separately with the Securities and
  Exchange Commission pursuant to a request for confidential treatment.

<PAGE>

(2)  Settlement of Accounts. Transportation furnished hereunder shall be
included in the monthly settlement of accounts in the same manner as other
transportation sales between the parties, which shall be as per the applicable
clearing house rules.

(3)  Collection of Applicable Fares. Except for Through Flights, all other
charges with respect to transportation furnished hereunder, including charges
for excess baggage, shall be governed by each party's applicable tariffs, rules
and regulations.

(4)  Responsibility for Compliance with Conditions. Both Carriers agree to see
that its agents comply with the terms and conditions of this Agreement. Should
the terms and conditions of this Agreement be violated by a Carrier or its
agents, the Carrier in violation agrees to reimburse the other Carrier for any
and all losses or damages incurred as a result thereof.

Section 16.  Ticket Handling

(1)  As applicable, Frontier or Great Lakes will use its own ticket
documentation for ticket sales made by that carrier.

(2)  Ticket Acceptance. For the term of this Agreement, Frontier and Great Lakes
shall accept the others flight documents written for Through Flights in
accordance with applicable restrictions. Neither Carrier shall endorse or refund
any such coupons without the others written consent, except in accordance with
the other's contract of carriage.

Section 17.  Compliance with Laws and Regulations

Frontier and Great Lakes shall provide the air transportation services performed
by each pursuant to this Agreement in compliance with all applicable statutes,
orders, rules and regulations of government agencies having jurisdiction over
their respective operations (including, but not limited to, FAA and DOT)
including (1) rules on notification of code share, wet lease and change of gauge
operations and (2) any conditions placed on approval of this Agreement.

Section 18.  Independent Parties

(1) Independent Contractors. It is expressly recognized and agreed that each
party, in its performance and otherwise under this Agreement, is and shall be
engaged and acting as an independent contractor and in its own independent and
separate business; that each party shall retain complete and exclusive control
over its staff and operations, and the conduct of its business; and that each
party shall bear and pay all expenses, costs, risks and responsibilities
incurred by it in connection with its obligations under this Agreement. Neither
Frontier nor Great Lakes nor any officer, employee, representative, or agent of
Frontier or Great Lakes shall

<PAGE>

in any manner, directly or indirectly, expressly or by implication, be deemed to
be, or make any representation or take any action which may give rise to the
existence of, any employment, agent, partnership, or any other like relationship
as between Frontier and Great Lakes but each party's relationship as respects
the other party in connection with this Agreement is and shall remain that of an
independent contractor.

(2)  Status of Employees. The employees, agents and/or independent contractors
of Frontier shall be employees, agents, and independent contractors of Frontier
for all purposes, and under no circumstances shall be deemed to be employees,
agents, or independent contractors of Great Lakes. The employees, agents and
independent contractors of Great Lakes shall be employees, agents and
independent contractors of Great Lakes for all purposes, and under no
circumstances shall be deemed to be employees, agents, or independent
contractors of Frontier. In its performance under this Agreement, each party
shall act as an independent contractor and not as an agent for the other.
Frontier shall have no supervisory power or control over any employees, agents,
or independent contractors employed by Great Lakes, and Great Lakes shall have
no supervisory power or control over any employees, agents and independent
contractors employed by Frontier.

(3)  Liability for Employee Costs. Each party, with respect to its own employees
(hired directly or through a third party), accepts full and exclusive liability
for the payment of worker's compensation and/or employer's liability (including
insurance premiums where required by law) and for the payment of all taxes,
contributions or other payments for unemployment compensation, vacations, or old
age benefits, pensions and all other benefits now or hereafter imposed upon
employers with respect to its employees by any government or agency thereof or
any other party (whether measured by the wages, salaries, compensation or other
remuneration paid to such employees or otherwise) and each party further agrees
to make such payments and to make and file all reports and returns, and to do
everything necessary to comply with the laws imposing such taxes, contributions
or other payments.

Section 19.  Release and Indemnification

(1)  Great Lakes Indemnity. Great Lakes agrees to release, indemnify, hold
harmless and defend Frontier, its officers, directors, employees, agents,
successors and assigns, from and against any and all claims, losses, damages,
liabilities, causes of action, suits, judgments and expenses, whether groundless
or not, including, but not limited to, reasonable attorneys' fees, costs and
related expenses,

     (a)  for bodily or personal injury, including death, to any persons
occurring while such persons are in the custody of, or being transported by
Great Lakes, including, but not limited to, employees of Great Lakes, except for
injury or death of

<PAGE>

Frontier's employees incurred in the performance of their duty and for which
workers' compensation is normally recoverable.

     (b)  for any loss of, damage to, or destruction of any property occurring
while such property is in the control or custody of, or being transported by
Great Lakes, including loss of use and consequential damage thereof (excluding,
however, loss of, damage to, or destruction of Frontier's property),

The foregoing indemnification shall not apply to any such claims or liability
resulting from the gross negligence or willful misconduct of Frontier, its
officers, directors, employees or agents.

(2)  Frontier Indemnity. Frontier agrees to release, indemnify, hold harmless
and defend Great Lakes, its officers, directors, employees, agents, successors
and assigns, from and against any and all claims, losses, damages, liabilities,
causes of action, suits, judgments and expenses, whether groundless or not,
including, but not limited to, reasonable attorneys' fees, costs and related
expenses,

     (a)  for bodily or personal injury, including death, to any persons
occurring while such persons are in the custody of, or being transported by
Frontier, including, but not limited to, employees of Frontier, except for
injury or death of Great Lakes' employees incurred in the performance of their
duty and for which workers' compensation is normally recoverable.

     (b)  for any loss of, damage to, or destruction of any property occurring
while such property is in the control or custody of, or being transported by
Frontier, including loss of use and consequential damage thereof (excluding,
however, loss of, damage to, or destruction of Great Lakes' property),

     (c)  for trademark or trade name infringement, arising out of or in any
manner connected with the use of the F9* designator code, on flights operated by
Great Lakes pursuant to this Agreement,

The foregoing indemnification shall not apply to any such claims or liability
resulting from the gross negligence or willful misconduct of Great Lakes, it
officers, directors, employees or agents.

(3)  Frontier Ground Services. To the extent that Frontier furnishes ground
services to Great Lakes in connection with F9* Code Share Service, Frontier
agrees to release, indemnify, hold harmless and defend Great Lakes, its
officers, directors, employees, agents, successors and assigns, from and against
any and all claims, losses, damages, liabilities, causes of action, suits,
judgments and expenses, whether groundless or not, including, but not limited
to, reasonable attorneys' fees, costs and related expenses, for bodily or
personal injury, including death, to any persons, including, but not limited to,
employees of Frontier, except for injury or death of Great Lakes' employees
incurred in the performance of their duties and for which workers' compensation
normally is

<PAGE>

recoverable, and for any loss of, damage to, or destruction of any property,
including loss of use and consequential damage thereof arising out of or in any
manner connected with the furnishing of services, materials or facilities by
Frontier hereunder, whether or not occurring or arising out of the negligence,
whether active, passive or any other type, of Frontier, its officers, directors,
employees or agents; however, the foregoing indemnification shall not apply to
any such claims of liability resulting from the gross negligence, willful
misconduct of Great Lakes, its officers, directors, employees or agents.

Section 20.  Insurance

(1)  Frontier and Great Lakes each shall maintain in full force and effect at
least the following insurance coverage's:

     (a)  Workers' Compensation and Occupational Disease insurance subject to
the laws of the state wherein this Agreement is being performed. Such coverage
shall include Employers Liability up to a limit of at least $500,000 USD.

     (b)  All Risk Aircraft Hull insurance shall include endorsements that:

          (i)  Provide that the insurer shall waive its subrogation rights
against the other carrier.

          (ii) Provide that, as respects the interest of the other carrier, this
insurance shall not be invalidated by any breach of warranty.

     (c)  Comprehensive Airline Liability insurance with limits no less than
$300,000,000 USD combined single limit per occurrence, including but not limited
to aircraft liability, passenger legal liability, and premises liability. Such
insurance shall include personal injury and contractual liability.

     (d)  The Comprehensive Airline Liability insurance referenced above shall
provide that:

          (i)    Underwriters acknowledge that the indemnification and hold
harmless provisions of this Agreement are insured under respective carriers'
blanket contractual liability coverage.

          (ii)   Frontier and Great Lakes are named as an additional insured on
the other's policy for such insurance.

          (iii)  Said insurance is primary with respect to the matters within
such coverage, irrespective of any insurance carried by the other carrier.

          (iv)   Provide that, as respects the interests of each carrier, this
insurance shall not be invalidated by any breach

<PAGE>

of warranty by the other carrier.

          (v)  Provide a severability of interest/cross liability endorsement.

(2)  Certificates. Within thirty (30) days of the commencement of this Agreement
and annually thereafter, certificates of insurance shall be delivered to each
carrier evidencing compliance by the other Carrier with the insurance terms of
this Agreement. All of the above insurance shall be written through a company or
companies reasonably satisfactory to the carrier receiving the benefit of the
certificate and the certificates of insurance shall be of a type that
unconditionally obligates the insurer to notify the carrier receiving the
benefit of the certificate in writing at least thirty (30) days in advance of
effective date in the event of any material change in, nonrenewal, or
cancellation of such insurance. Except in the case of Hull War Risk Insurance,
such period of notice shall be seven (7) days or less in accordance with the
applicable Insurance policy.

Section 21.  Directors, Officers, Agents, Employees

No director, officer, agent or employee of either party shall be charged
personally or held contractually liable by or to the other party under any term
or provision of this Agreement or any supplement, modification or amendment to
this Agreement or because of any breach thereof.

Section 22.  Effective Date and Term;  Termination

(1)  Effective Date and Term

     (a)  This Agreement shall become effective on the date first written above,
or as soon thereafter as executed by both parties (the "Effective Date") and
shall remain in effect continuously thereafter. Either Great Lakes or Frontier
may deliver to the other advance written notice of termination which notice
provides for a termination date for this Agreement at least 180 days subsequent
to delivery of the notice of termination (the "Termination Date"), provided that
neither party may deliver such notice prior to the Implementation Date.

          (i)  In the event of a change of control of either carrier, in which
the carrier is not the surviving carrier ("new company"), the new company may
deliver a notice of termination which will provide for a termination date of 360
days subsequent to delivery of the notice of termination.

     (b)  Code Share Services established and published in the printed and
electronic media under this Agreement shall be for the entire forward booking
period in accord with each media's policies as generally applied to forward
airline schedules (currently approximately 331 days). The parties agree that the
forward booking period shall be truncated to the Termination

<PAGE>

Date if and when notice of termination is given. The truncation shall be
effected with the next normally scheduled transmission of schedule data to the
various media. The parties also agree that any code share passengers booked and
ticketed for travel during the forward booking period while such code share
service was published will be serviced in accord with operating procedures
established by the parties pursuant to this Agreement, even though the Agreement
may have been terminated subsequent to such booking and ticketing.

(2)  Termination

     (a)  In the event that either Great Lakes or Frontier (i) makes a general
assignment for the benefit of creditors or becomes insolvent; (ii) files a
voluntary petition in bankruptcy; (iii) petitions for or acquiesces in the
appointment of any receiver, trustee or similar officer to liquidate or conserve
its business or any substantial part of its assets; (iv) commences under the
laws of any competent jurisdiction any proceeding involving its insolvency,
bankruptcy, reorganization, readjustment of debt, dissolution, liquidation or
any other similar proceeding for the relief of financially distressed debtors;
(v) becomes the object of any proceeding or action of the type described in
(iii) or (iv) above and such proceeding or action remains undismissed or
unstayed for a period of at least sixty (60) days; or (vi) is divested of a
substantial part of its assets so as to affect the ability to operate its
business generally for a period of at least thirty (30) days; then the other
party may by written notice terminate this Agreement immediately.

Section 23.  Default

(1)  Cure Period and Termination. Except as otherwise provided herein, if
either party shall default in performance of any of the terms, covenants and
conditions of this Agreement, the other party may give notice of such default to
the party at default. In the event such default is not cured within (a) thirty
(30) days after the giving of such notice or (b) five (5) business days in the
case of the failure to make any payments due and payable under the Agreement,
the party giving notice may terminate this Agreement effective upon such date
that party specifies by further notice to the party in default, without
prejudice to any other rights which the other party may have.

(2)  No Waiver. The waiver by either party of performance of any term, covenant
or condition of this Agreement in a particular instance shall not constitute a
waiver of any subsequent breach or preclude such party from thereafter demanding
performance thereof according to the terms hereof.

Section 24.  Force Majeure, etc.

(1)  Neither party shall be liable to the other for any failure to comply with
the terms of this Agreement or any loss, injury, damage or delay whatsoever
resulting, directly or indirectly, from one or more of the following: act of
God; seizure under legal

<PAGE>

process; governmental sanctions; quarantine restrictions; fire, fog, flood, or
other weather-related reason; failure or refusal on the part of any government
or governmental agency to grant or issue approvals, clearances, exemptions,
permits or operating authority, or recession or revocation thereof by any
government or governmental agency; damage to or destruction of aircraft or other
flight equipment; mechanical difficulties or breakdowns; unavailability of fuel;
riots or civil commotion; strikes, lockouts or labor disputes (whether resulting
from disputes between either party and its employees or between other parties);
U.S. military or airlift emergency or substantially expanded U.S. military
airlift requirements as determined by the U.S. government; activation of the
U.S. Civil Reserve Air Fleet; war or hazards or dangers incident to a state of
war; or any other acts, matters or things, whether or not of a similar nature,
which are beyond the control of either party and which shall directly or
indirectly, prevent, delay, interrupt, or otherwise adversely affect the
furnishing, operation or performance of such transportation.

(2)  Frontier or Great Lakes shall have the right to terminate this Agreement
forthwith in the event of an airlift emergency as determined by the United
States Secretary of Defense or his designee or by the Commander of the United
States Military Airlift Command, or if the United States Civil Reserve Air Fleet
is activated by order of the Secretary of Defense, and, as a direct result,
Frontier scheduled service in Denver is reduced by 50%.

Section 25. Taxes

(1)  Subject to Section 25(4), each party shall be responsible for any net or
gross income or franchise taxes (or taxes of a similar nature) on the revenues
or income or any measure thereof which is attributable to it in connection with
the sale of air transportation pursuant to this Agreement.

(2)  The Ticketing Carrier, shall collect, except as otherwise prohibited by
law, all Ticket Taxes relating to tickets sold or travel documents issued by it
with respect to air transport pursuant to this Agreement. The parties hereby
agree:

        (a) The Ticketing Carrier, shall collect, report and remit to the
Operating Carrier any non-interlineable Ticket Taxes levied in connection with
sales of the Codeshare Flights.

        (b) The Ticketing Carrier shall collect, report and credit to the
account of the Operating Carrier with ACH any interlineable Ticket Taxes levied
in connection with the sales of the Codeshare Flights. The Operating Carrier
shall remit to taxing authorities all such interlineable Ticket Taxes.

        (c) The Operating Carrier may bill the Ticketing Carrier for any Ticket
Taxes due or payable on or measured by passenger enplanement and payable or
remittable by the Operating Carrier which should have been collected at the time
of ticket sale or travel document issue.

<PAGE>

(3)  If either party receives notice from any taxing authority with respect to
any assessment or potential assessment or imposition of any Tax (collectively,
an "Assessment"), that the other party may be responsible for paying, directly
or indirectly, the party so notified shall inform the other party in writing
within ten (10) days of receipt of such notice. If the party receiving such
notice from a taxing authority is or will be required to pay any Assessment for
which the other party is ultimately responsible, it shall be entitled to be
indemnified against such Assessment in accordance with Section 25(4).

(4)  Each party further agrees to indemnify, defend and hold harmless the other
from and against any and all Taxes, or Assessments, as the case may be, levied
upon or advanced by the indemnified party, but that ultimately the indemnifying
party would be responsible for paying, which resulted from any transaction or
activity contemplated by this Agreement.

Section 26.  Notices

All notices, requests, demands and other communications hereunder shall be in
writing, transmitted by overnight, registered, or certified mail, and shall be
deemed to have been duly given when actually received. Notices shall be
transmitted:

        (a)    if to Great Lakes to the attention of:
               Great Lakes Aviation, Ltd.
               1022 Airport Parkway
               Cheyenne, Wyoming 82001
               Attention: President

        (b)    if to Frontier to the attention of:
               Frontier Airlines, Inc.
               Frontier Center One
               7001 Tower Road
               Denver, Colorado 80249-7312
               Attn: Vice President, Market Planning; Revenue Management

        (c)    Or, in each case, to such other person and place as Frontier or
Great Lakes furnish to the other party in writing.

Section 27.  Miscellaneous Provisions

(1)  Other Agreements. Except as set forth in Section 2, nothing herein
contained, shall prevent either Carrier from entering into agreements with other
carriers that provide for joint marketing of operations or code sharing.

(2)  Governing Law. This Agreement shall be interpreted in accordance with, and
performance shall be governed by, the laws of the State of Colorado, United
States of America, regardless of the laws that might be applicable under
principles of conflict of law.

<PAGE>

Each party shall attempt to mediate any disputes, which might arise from this
agreement prior to filing a complaint with a court of competent jurisdiction.
Both parties consent to the jurisdiction of such Court.

(3)  Counterparts. This Agreement may be executed simultaneously in counterparts
each of which shall be deemed an original, but all of which together shall
constitute one and the same instrument.

(4)  Entire Agreement. This Agreement, including the Exhibits which are attached
hereto and made part hereof, sets forth the entire Agreement and understanding
between the parties as to the subject matter hereof, and merges and supercedes
all prior discussions, agreements and understandings concerning the subjects
covered by this Agreement. No party shall be bound by any term, condition or
definition other than expressly set forth or provided for in this Agreement or
amendments to this Agreement. Unless expressly provided herein, this Agreement
may not be changed or modified, except by agreement in writing, signed by the
party to be bound thereby.

(5)  Waiver, Construction, Severability, No Third party Beneficiary. No waiver
of any breach of this Agreement shall be held to constitute a waiver of any
other or subsequent breach. This Agreement shall not be construed against the
party preparing it, but shall be construed as if both parties jointly prepared
it and any uncertainty or ambiguity shall not be interpreted against either
party. In the event that any one or more of the provisions of this Agreement
shall be determined to be invalid, unenforceable, or illegal, such invalidity,
unenforceability or illegality shall not affect any other provision of this
Agreement and the Agreement shall be construed as if such invalid, unenforceable
or illegal provision had never been contained herein. No person or entity, other
than Frontier or Great Lakes, shall have any rights, claims, benefits or powers
under this agreement and this agreement shall not be construed or interpreted to
confer any rights, claims, benefits or powers upon any third party. There are no
third-party beneficiaries of this agreement.

(6)  Assignment. This Agreement shall not be assigned by either party without
the prior written consent of the other party; provided that either party may,
without such consent, assign any of its fixed or contingent rights to receive
money payments hereunder and shall promptly notify the other party in writing of
any such assignment.

(7)  Not a Partnership. The terms of this Agreement, including its annexes and
appendices, or any supplement, modification, or amendment to this Agreement
shall not be construed or interpreted at any time to mean that the business
relationship between Frontier and Great Lakes is a partnership.

The parties hereto have caused this Code Share Agreement to be executed in their
names and on their behalf by their respective officers duly authorized, on the
day and year first above written.

<PAGE>

FRONTIER AIRLINES, INC.             GREAT LAKES AVIATION, LTD

By: __________________________      By: ______________________________

Its: _________________________      Its: _____________________________

EXHIBIT A

City Pair                      City Name                      Effective Date
---------                      ---------                      --------------

DEN-AIA                        Alliance, NE
DAN-ALS                        Alamosa, CO
DEN-AMA                        Amarillo, TX                   July 9, 2001
DEN-BFF                        Scottsbluff, NE
DEN-CDR                        Chadron, NE
DEN-CEZ                        Cortez, CO
DEN-CNY                        Moab, UT
DEN-COD                        Cody, WY                       July 9, 2001
DEN-CPR                        Casper, WY                     July 9, 2001
DEN-CYS                        Cheyenne, WY                   July 9, 2001
DEN-DDC                        Dodge City, KS
DEN-DIK                        Dickinson, ND
DEN-DRO                        Durango, CO

<PAGE>

DEN-EAR                      Kearney, NE
DEN-EGE                      Eagle/Vail, CO
DEN-FMN                      Farmington, NM
DEN-GCC                      Gillette, WY                       July 9, 2001
DEN-GCK                      Garden City, KS
DEN-GJT                      Grand Junction, CO
DEN-GRI                      Grand Island, NE
DEN-GUC                      Gunnison, CO
DEN-HDN                      Hayden/SteamboatSprings,CO         July 9, 2001
DEN-HYS                      Hays, KS
DEN-ISN                      Williston, ND
DEN-JAC                      Jackson, WY
DEN-LAR                      Laramie, WY
DEN-LBF                      North Platte, NE
DEN-LBL                      Liberal, KS
DEN-MCK                      McCook, NE
DEN-MTJ                      Montrose, CO
DEN-OFK                      Norfolk, NE
DEN-PGA                      Page, AZ
DEN-PIR                      Pierre, SD
DEN-PUB                      Pueblo, CO
DEN-RAP                      Rapid City, SD
DEN-RIW                      Riverton, WY
DEN-RKS                      Rock Springs, WY
DEN-SAF                      Santa Fe, NM                       July 9, 2001
DEN-SHR                      Sheridan, WY
DEN-SLN                      Salina, KS
DEN-TEX                      Telluride, CO
DEN-VEL                      Vernal, UT
DEN-WRL                      Worland, WY
MSP-BKX                      Brookings, SD
MSP-DVL                      Devils Lake, ND

<PAGE>

MSP-HON                      Huron, SD
MSP-IMT                      Iron Mountain, MI
MSP-IWD                      Iron Wood, MI
MSP-JMS                      Jamestown, ND
PHX-PGA                      Page, AZ

          ATTACHMENT B - Prorate fares - published high y as of 4/26/01

                                      * - with tax

                    ABQ               $     *

                    ATL               $     *

                    BOS               $     *

                    BWI               $     *

                    DCA               $     *

                    DFW               $     *

                    ELP               $     *

                    IAH               $     *

                    LAS               $     *

                    LAX               $     *

                    LGA               $     *

                    MCI               $     *

                    MCO               $     *

                    MDW               $     *

                    MSP               $     *

                    OMA               $     *

                    PDX               $     *

* Confidential material omitted and filed separately with the Securities and
  Exchange Commission pursuant to a request for confidential treatment.

<PAGE>

                    PHX               $     *

                    SAN               $     *

                    SEA               $     *

                    SFO               $     *

                    SLC               $     *

                    AMA               $     *

                    CPR               $     *

                    CYS               $     *

                    COD               $     *

                    GCC               $     *

                    HDN               $     *

                    SAF               $     *

* Confidential material omitted and filed separately with the Securities and
  Exchange Commission pursuant to a request for confidential treatment.

<PAGE>

                               AMENDMENT NO. 1 TO
                               CODESHARE AGREEMENT

     This Amendment No. 1 (the "Amendment") is made and entered into as of
February 8, 2002 (the "Effective Date"), by and between Frontier Airlines, Inc.
("Frontier"), a corporation organized under the laws of Colorado, and Great
Lakes Aviation Ltd. ("Great Lakes"), a corporation organized under the laws of
Iowa.

RECITALS:

     A.   Frontier and Great Lakes have entered into a Codeshare Agreement,
          dated as of May 3, 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.   Frontier has also entered into a codeshare agreement with Mesa
          Airlines, Inc.

NOW, THEREFORE, in consideration of the recitals and for other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged,
Great Lakes and Frontier agree to amend the Codeshare Agreement as follows:

     1.   Add the following new Section 2(4): In consideration for the
          reservation services, CRS fees, credit card charge commissions, and
          certain ticketing services provided by Frontier under the Codeshare
          Agreement, Great Lakes agrees to pay to Frontier a * per passenger fee
          for passengers flying solely on connecting routes that involve flight
          segments operated by both Mesa and Great Lakes under the F9 code;
          i.e., connecting routes that do not involve any Frontier-operated
          segments.

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

                                        GREAT LAKES AVIATION, LTD.

                                        By:  /s/ Douglas G. Voss
                                             -----------------------------------
                                        Name:  Douglas G. Voss
                                        Title:  President

                                        FRONTIER AIRLINES, INC.

                                        By:  /s/ Sean Menke
                                             -----------------------------------
                                        Name:  Sean Menke
                                        Title:  VP Marketing

* Confidential material omitted and filed separately with the Securities and
Exchange Commission pursuant to a request for confidential treatment.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00051-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00051-of-00352.parquet"}]]