Exhibit 10

                                AMENDMENT NO. 13
                                       TO
                            AIRLINE LEASE NO. AC-865


          THIS AMENDMENT TO CONTRACT OF LEASE is made and entered into as of the
5th  day  of  April,   1999,  by  and  between  MILWAUKEE  COUNTY,  a  municipal
corporation,  organized  and  existing  as  one  of the  counties  in  Wisconsin
(hereinafter referred to as "Lessor" or "County"), and MIDWEST EXPRESS AIRLINES,
INC.,  a  corporation  organized  and  existing  under  the laws of the State of
Wisconsin (hereinafter referred to as "Lessee" or "Airline").

                              W I T N E S S E T H:

          THAT,  WHEREAS,  the parties  hereto have  heretofore  entered into an
Airline Lease dated April 5, 1985, as amended,  relating to space, occupancy and
the use of the premises and facilities of General Mitchell International Airport
(GMIA) for the transportation of persons and cargo by air; and

          WHEREAS,  Airline  requests  that Lessor assign  approximately  15,000
square feet of additional  space under gates D-39,  D-52,  D-53,  D-55, and D-56
which Airline will improve at Airline's cost; and,

          WHEREAS,  Airline has requested to make improvements to other areas of
the terminal  building  currently under lease to Airline at Airline's cost which
changes the amount of space under lease to Airline; and,

          WHEREAS,  on May  22,  1998,  (File  No.  98-310)  County's  Board  of
Supervisors approved amending Airline's Lease to include space under gates D-39,
D-52, D-53, D-55, and D-56;

          WHEREAS,  Airline  has  requested  and  County  has  consented  to the
issuance of rental credits to reimburse  Airline for the cost which County would
otherwise  incur on behalf of the Airline to improve said  approximately  15,000
square feet of lower level space;

          NOW,  THEREFORE,  for and in  consideration of the premises and of the
mutual   covenants  and   agreements   herein   contained  and  other   valuable
considerations,  it is  mutually  agreed  between  the  parties  hereto that the
aforesaid agreement dated April 5, 1985, as amended, be and it is hereby further
amended in the following particulars, to wit:

          1. In order to establish a base document  which  summarizes  all space
occupied  by  Airline,  Exhibit "P" Base  Document  6/98,  pages 1 through 14 is
attached hereto and made a part hereof, containing all space occupied by Airline
as of 6/98 and replaces all previous Exhibit "P" pages.

          2.  Effective  on July 15,  1998,  paragraph  S of Article IV shall be
deleted in its entirety  and a new  paragraph S inserted  therefore,  reading as
follows:

<PAGE>

          "S. LESSEE'S  EXCLUSIVE USE SPACE WITHIN THE TERMINAL BUILDING ON JULY
1, 1998

          For purposes of calculation of Lessee's Terminal rents for those areas
designated for Lessee's  exclusive use in the Terminal  Building,  the following
space definitions, relative cost factors, and resultant ERUs shall be utilized:

                                                   Relative      
    Space Function                    Sq. Ft.      Cost Factor        ERUs
    --------------                    -------      -----------        ----
Concourse Lower Level                     -0-            .20            -0-
Office Unfinished 
(Unheated)

Concourse Lower Level                5,262.50            .70       3,683.75
Office Finished
(Heated)
Concourse Lower Level               36,040.90            .85      30,634.77
Office Finished
(Heated & Air Conditioned)
Concourse Upper Level                     -0-            .95            -0-
Office Unfinished
Concourse Upper Level                  945.00            .95         897.75
Office Finished 
Ticket Counter                         661.70           1.10         727.87

Ticket County Office                 1,307.40            .95       1,242.03

Gate Hold Rooms                     29,518.00           1.00      29,518.00

Baggage Makeup Area                  3,939.10            .75       2,954.33

Baggage Service Office                 405.00           1.00         405.00

Hold Room Stairwell                  2,625.44            .15         393.82

Basement                                    0            .25              0

Mezzanine Office Areas                      0            .90              0

Operations Control tower               401.00           1.08         433.08

TOTALS                              81,106.04                     70,890.40


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<PAGE>


The spaces  outlined above are those occupied by Lessee on July 15, 1998,  which
deletes 191 square feet of Concourse  Lower Level Office  Unfinished  (Unheated)
space, and includes an additional  1,157.50 square feet of Concourse Lower Level
Office  finished  (Heated)  space,  8,197 square feet of  Concourse  Lower Level
Office finished (Heated and Air Conditioned) space, 112 square feet of Concourse
Upper level Office  Finished  space,  3,457 square feet of Gate Hold Room space,
and 550 feet of Hold Room Stairwell space, as shown on Exhibit "P", pages 6, 12,
13 and 14 of 14, Revised 7/15/98, attached hereto and made a part hereof."

          3. Except as specifically provided herein, the terms and conditions of
the Lease  heretofore  entered into between the parties  dated April 5, 1985, as
amended, shall remain in full force and effect.

          IN WITNESS  WHEREOF,  the parties hereto have caused these presents to
be signed by their  respective  proper officers and their corporate seals hereto
affixed on the dates hereinafter set forth.

                                     COUNTY

          Dated at Milwaukee, Wisconsin, this 5th day of April, 1999.

APPROVED:                                   MILWAUKEE COUNTY
                                            a municipal corporation



/s/                      3/31/99            By /s/ William Heinemann   4/2/99
----------------------------------             -------------------------------
Airport Director           Date                William Heinemann
                                               Acting Director of Public Works


/s/                      3/31/99            By /s/ Mark E. Ryan        4/5/99
----------------------------------             -------------------------------
Corporation Counsel        Date                Mark E. Ryan
                                               County Clerk, Deputy

                                     AIRLINE

          Dated at Milwaukee, Wisconsin, this 23rd day of March, 1999.

                                            MIDWEST EXPRESS AIRLINES, INC.
                                            a Wisconsin corporation


                                            By /s/ Robert S. Bahlman  
                                               ------------------------------
                                               Robert S. Bahlman
                                            Title:  Sr. Vice President
                                            Date: March 23, 1999


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