<PAGE>   1
                                                                   Exhibit 10(d)

                  AMENDMENT TO LOAN SUBPARTICIPATION AGREEMENT
                  --------------------------------------------


         THIS AMENDMENT TO LOAN SUBPARTICIPATION AGREEMENT (this "Amendment") is
made as of March 1, 2001, between AIRBASE REALTY HOLDING COMPANY, an Indiana
corporation ("Transferor") and AIRBASE REALTY COMPANY, an Ohio corporation
("Transferee").

                                    RECITALS
                                    --------

         A. The parties have previously entered into a certain Loan
Subparticipation Agreement, dated as of May 1, 1998 (the "Subparticipation
Agreement"). (All capitalized terms used in this Amendment and not otherwise
defined herein shall have the meanings ascribed to such terms in the
Subparticipation Agreement.)

         B. The Subparticipation Agreement was made in connection with a certain
Loan Participation Agreement, also dated as of May 1, 1998, between The
Huntington National Bank (the "Bank") and Transferor (the "Participation
Agreement").

         C. The Participation Interest granted under the Participation Agreement
represented a 95% interest in each of the Loans and the Participation Interest
granted under the Subparticipation Agreement represented a 100% interest in the
Participation Interest granted under the Participation Agreement.

         D. The outstanding principal balance of the Loans as of February 28,
2001, is $6,185,810,018, and the outstanding principal balance of the current
Participation Interest in such Loans is $5,876,519,517.

         E. Simultaneously with the execution of this Amendment, the Bank and
the Transferor have executed an amendment to the Participation Agreement (the
"Participation Agreement Amendment") whereby the Participation Interest granted
under the Participation Agreement is being increased from 95% to 99% in exchange
for the payment by Transferor to the Bank of $247,432,401 in cash.

         F. The parties desire to provide for the increase of the Participation
Interest under the Subparticipation Agreement by virtue of the increase in the
Participation Interest under the Participation Agreement and otherwise to modify
the Subparticipation Agreement as set forth herein.

                                    AGREEMENT
                                    ---------

         The parties hereby agree as follows:

         1. In consideration of the transfer by Transferor to Transferee of an
additional 4% Participation Interest in the Loans, effected by the execution of
the Participation Agreement

<PAGE>   2

Amendment, Transferee has, simultaneously with its execution of this Amendment,
transferred the sum of $247,432,401 in cash to the Transferor.

         2. The Subparticipation Agreement is hereby modified and amended,
effective as of the date hereof, by deleting the first sentence of paragraph 2
of the Subparticipation Agreement in its entirety and substituting the following
in lieu thereof:

         Transferee shall from time to time buy from Transferor or from an
         affiliate of Transferor, without recourse, a continuing undivided
         fractional Participation Interest in the Loans, and Transferor shall
         from time to time sell to Transferee, or cause an affiliate or
         affiliates of Transferor to sell to Transferee, such Participation
         Interests. The consideration for the transfer of the initial
         Participation Interests to be transferred to Transferee hereunder shall
         be the issuance to Transferor of all 750 shares of the common stock of
         Transferee and 896 shares of the Class A Preferred Stock of Transferee.
         Subsequent transfers of Participation Interests by Transferor or an
         affiliate of Transferor to Transferee hereunder may, upon the mutual
         agreement of the parties at the time any such transfers are made, be
         made (i) as additional contributions to the capital of Transferee, (ii)
         in exchange for the payment of cash by Transferee to Transferor or
         appropriate affiliate of Transferor, (iii) in consideration of the
         issuance to Transferor or appropriate affiliate of Transferor of shares
         of the capital stock of Transferee, or (iv) for such other
         consideration as the parties shall mutually agree.

         3. Except as specifically modified and amended herein, the
Subparticipation Agreement shall remain unchanged and in full force and effect.

         IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date set forth above.

                                         AIRBASE REALTY HOLDING COMPANY


                                         By:  /s/ Gregory C. Sheridan
                                              -----------------------
                                              Gregory C. Sheridan, President

                                         AIRBASE REALTY COMPANY


                                         By:  /s/ Steven A. Hinshaw
                                              ---------------------
                                              Steven A. Hinshaw, Vice President




                                      -2-