SUPPLEMENT NO. 4

                                       TO

                            SERIES 1998-1 SUPPLEMENT

                          dated as of February 18, 2000

                                      among

                            RENTAL CAR FINANCE CORP.,

                        DOLLAR RENT A CAR SYSTEMS, INC.,

                        THRIFTY RENT-A-CAR SYSTEM, INC.,

                     DOLLAR THRIFTY AUTOMOTIVE GROUP, INC.,

                             BANKERS TRUST COMPANY,
                        as Trustee and Enhancement Agent

                  CREDIT  SUISSE FIRST  BOSTON,  NEW YORK BRANCH,
                        as the Series 1998-1 Letter of
                                 Credit Provider

                                       and

                          DOLLAR THRIFTY FUNDING CORP.,
                      as the sole Series 1998-1 Noteholder

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                                SUPPLEMENT NO. 4
                           TO SERIES 1998-1 SUPPLEMENT

     This Supplement No. 4 to Series 1998-1  Supplement dated as of February 18,
2000  ("Supplement  No.  4"),  among  Rental  Car  Finance  Corp.,  an  Oklahoma
corporation ("RCFC"),  Dollar Rent A Car Systems,  Inc., an Oklahoma corporation
("Dollar"),   Thrifty   Rent-A-Car   System,   Inc.,  an  Oklahoma   corporation
("Thrifty"),  Dollar  Thrifty  Automotive  Group,  Inc., a Delaware  corporation
("DTAG"), Bankers Trust Company, a New York banking corporation,  as Trustee and
Enhancement Agent (the "Trustee"),  Credit Suisse First Boston, New York Branch,
as the Series  1998-1 Letter of Credit  Provider  ("CSFB"),  and Dollar  Thrifty
Funding Corp.,  an Oklahoma  corporation,  as the sole Series 1998-1  Noteholder
("DTFC")(RCFC,   Dollar,   Thrifty,   DTAG,  the  Trustee,  CSFB  and  DTFC  are
collectively referred to herein as the "Parties").

                                    RECITALS:

         A.  RCFC, as Issuer, and the Trustee  entered  into that  certain  Base
Indenture  dated as of December  13, 1995,  as amended by the  Amendment to Base
Indenture dated as of December 23, 1997 (the "Base Indenture"); and

         B.  RCFC and the  Trustee  entered  into  that  certain  Series  1998-1
Supplement  dated as of March 4, 1998, as subsequently  (i) amended by Amendment
No. 1 to Series 1998-1  Supplement dated as of March 4, 1999, (ii)  supplemented
by Supplement No. 1 to Series 1998-1 Supplement dated as of March 4, 1999, (iii)
supplemented by Supplement No. 2 to Series 1998-1  Supplement  dated as of March
4, 1999, and (iv)  supplemented by Supplement No. 3 to Series 1998-1  Supplement
dated as of October 20, 1999 (as amended to the date hereof,  the "Series 1998-1
Supplement"; the Base Indenture and any Supplement thereto, including the Series
1998-1 Supplement are collectively referred to herein as the "Indenture"); and

        C. The Parties wish to amend the Series 1998-1  Supplement  as  provided
herein.

         NOW THEREFORE, the Parties hereto agree as follows:

     1. Definitions.  Capitalized terms used in this Supplement No. 4 not herein
defined shall have the meaning  contained in the Series 1998-1 Supplement and if
not defined  therein  shall have the meaning set forth in the  Definitions  List
attached as Schedule 1 to the Base Indenture.

     2.  Amendments.  Section  4A.1 of the Series  1998-1  Supplement  is hereby
amended by deleting  the  reference  to  "$640,000,000"  and  replacing  it with
"$780,000,000".

     3.  Effect of  Supplement.  Except as  expressly  set  forth  herein,  this
Supplement No. 4 shall not by implication or otherwise limit, impair, constitute
a waiver of, or  otherwise  affect the rights and remedies of any of the Parties
hereto under the Series 1998-1 Supplement,  nor alter,  modify,  amend or in any
way affect any of the terms, conditions, obligations, covenants or

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agreements  contained in the Series 1998-1  Supplement,  all of which are hereby
ratified and affirmed in all  respected by each of the Parties  hereto and shall
continue  in full force and  effect.  This  Supplement  No. 4 shall apply and be
effective  only with respect to the  provisions of the Series 1998- 1 Supplement
specifically  referred  to  herein  and  any  references  in the  Series  1998-1
Supplement  to the  provisions  of the  Series  1998-1  Supplement  specifically
referred to herein shall be to such provisions as amended by this Supplement No.
4.

     4.  Applicable  Provisions.  Pursuant to Section 11.2 of the Base Indenture
and  Section  8.6 of the  Series  1998-1  Supplement,  the  Trustee,  RCFC,  the
Servicers,  the Required Noteholders with respect to the Series 1998-1 Notes and
the Series 1998-1  Letter of Credit  Provider may enter into a supplement to the
Indenture  for the  purpose of  amending  any  provisions  of the Series  1998-1
Supplement  provided that the Rating Agencies shall confirm that such supplement
will not result in the reduction or  withdrawal  of their ratings  applicable to
the  Commercial  Paper Notes and, as  evidenced  by an Opinion of Counsel,  such
supplement affects only the Series 1998-1 Noteholders.

     5. Waiver of Notice. Each of the Parties hereto waives any prior notice and
any notice  period that may be required  by any other  agreement  or document in
connection with the execution of this Supplement No. 4.

     6. Binding Effect. This Supplement No. 4 shall be binding upon and inure to
the benefit of the Parties and their respective successors and assigns.

     7.  GOVERNING  LAW. THIS  SUPPLEMENT NO. 4 SHALL BE CONSTRUED IN ACCORDANCE
WITH THE LAWS OF THE STATE OF NEW YORK (WITHOUT  GIVING EFFECT TO THE PROVISIONS
THEREOF REGARDING  CONFLICTS OF LAWS), AND THE OBLIGATIONS,  RIGHTS AND REMEDIES
OF THE PARTIES HERETO SHALL BE DETERMINED IN ACCORDANCE WITH SUCH LAWS.

     8.  Counterparts.  This  Supplement  No. 4 may be executed in any number of
counterparts and by different parties hereto in separate  counterparts,  each of
which when executed and  delivered  shall be deemed to be an original and all of
which taken together shall constitute but one and the same agreement.

                         [SIGNATURES ON FOLLOWING PAGES]

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         IN WITNESS WHEREOF, the Parties have caused this Supplement No. 4 to be
duly executed and delivered as of the day and year first above written.

           RCFC:

           RENTAL CAR FINANCE CORP.,
           an Oklahoma corporation

           By: ___________________________________________
                    Pamela S. Peck
                    Vice President


           TRUSTEE:

           BANKERS TRUST COMPANY, a New York banking
           corporation, as Trustee and Enhancement Agent

           By: ___________________________________________
           Name: _________________________________________
           Title: ________________________________________


           SERVICERS:

           DOLLAR RENT A CAR SYSTEMS, INC.,
           an Oklahoma corporation

           By: __________________________________________
                    Michael H. McMahon
                    Treasurer

           THRIFTY RENT-A-CAR SYSTEM, INC.,
           an Oklahoma corporation

           By: __________________________________________
                    Pamela S. Peck
                    Treasurer


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<PAGE>


               DOLLAR THRIFTY AUTOMOTIVE GROUP, INC.,
               a Delaware corporation

               By: ______________________________________

                        Pamela S. Peck
                        Treasurer

               SERIES 1998-1 LETTER OF CREDIT PROVIDER:

               CREDIT SUISSE FIRST BOSTON, NEW YORK
               BRANCH, a Swiss banking corporation

               By: ______________________________________
               Name: ____________________________________
               Title: ___________________________________

               By: ______________________________________
               Name: ____________________________________
               Title: ___________________________________


               SOLE SERIES 1998-1 NOTEHOLDER:

               DOLLAR THRIFTY FUNDING CORP.,
               an Oklahoma corporation

               By: ______________________________________
                        Pamela S. Peck
                        Vice President




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