UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549


                                 SCHEDULE 13G



                   Under the Securities Exchange Act of 1934

                              (Amendment No. 3)*


                   INTERNATIONAL AIRLINE SUPPORT GROUP, INC.
                                (Name of Issuer)

                                 COMMON STOCK
                        (Title of Class of Securities)

                                   458865201
                                (CUSIP Number)

                               December 31, 1999
            (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

     [_] Rule 13d-1(b)
     [_] Rule 13d-(c)
     [_] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).

                               Page 1 of 5 pages


  CUSIP NO. 458865201                 13G                     Page 2 of 5 Pages


 1.   NAME OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOs. OF ABOVE PERSONS

          HEARTLAND ADVISORS, INC.

          #39-1078128

 2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                (a) [_]
                                                                (b) [_]

 3.   SEC USE ONLY


 4.   CITIZENSHIP OR PLACE OF ORGANIZATION


          WISCONSIN, U.S.A.


     NUMBER OF       5. SOLE VOTING POWER
      SHARES
   BENEFICIALLY         82,200
     OWNED BY
       EACH          6. SHARED VOTING POWER
    REPORTING           None
      PERSON
       WITH          7. SOLE DISPOSITIVE POWER
                        332,200

                     8. SHARED DISPOSITIVE POWER
                        None

 9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          332,200

10.   CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES


11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

          15.2%

12.   TYPE OF REPORTING PERSON

          IA


CUSIP NUMBER  458865201                 Page 3 Of 5 Pages

Item 1.

     (a) Name of Issuer: International Airline Support Group, Inc.
         --------------

     (b) Address of Issuer's Principal Executive Offices:
         -----------------------------------------------
               1954 Airport Road, Suite 200
               Atlanta, GA 30341

Item 2.

     (a) Name of Person Filing:    Heartland Advisors, Inc.
         ---------------------

     (b) Address of Principal Business Office:
         ------------------------------------
               Heartland Advisors, Inc.
               789 North Water Street
               Milwaukee, WI 53202

     (c) Citizenship:    Heartland Advisors is a Wisconsin corporation.
         -----------

     (d) Title of Class of Securities:  Common Stock
         ----------------------------

     (e) CUSIP Number:   458865201
         ------------

Item 3. If this statement is filed pursuant to (S)(S)240.13d-1(b) or
        ------------------------------------------------------------
        240.13d-2(b) or (c), check whether the person filing is a:
        ----------------------------------------------------------

     (a) [_]  Broker or Dealer registered under Section 15 of the Act
              (15 U.S.C. 78o).

     (b) [_]  Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c).

     (c) [_]  Insurance company as defined in Section 3(a)(19) of the Act
              (15 U.S.C. 78c).

     (d) [_]  Investment company registered under section 8 of the Investment
              Company Act of 1940 (15 U.S.C. 80a-8).

     (e) [X]  An investment adviser in accordance with
              (S)240.13d-1(b)(1)(ii)(E);

     (f) [_]  An employee benefit plan or endowment fund in accordance with
              (S)240.13d-1(b)(1)(ii)(F).


     (g) [_]  A parent holding company or control person in accordance with
              (S)240.13d-1(b)(ii)(G);

     (h) [_]  A savings association as defined in Section 3(b) of the Federal
              Deposit Insurance Act (12 U.S.C. 1813);

     (i) [_]  A church plan that is excluded from the definition of an
              investment company under section 3(c)(14) of the Investment
              Company Act of 1940 (15 U.S.C. 80a-3);

     (j) [_]  Group, in accordance with (S)240.13d-1(b)(1)(ii)(J).

If this statement is filed pursuant to (S)240.13d-1(c), check this box [_].

Item 4. Ownership.
        ---------

     (a)  Amount beneficially owned:
          --------------------------
          332,200 shares may be deemed beneficially owned within the meaning of
Rule 13d-3 of the Securities Exchange Act of 1934 by Heartland Advisors, Inc.

     (b)  Percent of class:
          ----------------
          15.2%

     (c)  For information on voting and dispositive power with respect to the
above listed shares, see Items 5-8 of the Cover Page.


Item 5. Ownership of Five Percent or Less of a Class.
        --------------------------------------------

          If this statement is being filed to report the fact that as of the
date hereof the reporting person has ceased to be the beneficial owner of more
than five percent of the class of securities, check the following: [_]


Item 6. Ownership of more than Five Percent on Behalf of Another Person.
        ---------------------------------------------------------------

        The shares of common stock to which this Schedule relates are held in
investment advisory accounts of Heartland Advisors, Inc. As a result, various
persons have the right to receive or the power to direct the receipt of
dividends from, or the proceeds from the sale of, the securities. The interests
of one such account, Heartland Value Fund, a series of Heartland Group, Inc., a
registered investment company, relates to more than 5% of the class.


Item 7. Identification and Classification of the Subsidiary Which Acquired the
        ----------------------------------------------------------------------
Security Being Reported on By the Parent Holding Company.
- --------------------------------------------------------

        Not Applicable.

Item 8. Identification and Classification of Members of the Group.
        ---------------------------------------------------------

        Not Applicable.

Item 9. Notice of Dissolution of Group.
        ------------------------------


         Not Applicable.

Item 10. Certification.
         -------------

         By signing below, I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired and are held in the
ordinary course of business and were not acquired and are not held for the
purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.


                                   SIGNATURE

         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

DATE:                 January 27, 2000

                      HEARTLAND ADVISORS, INC.

                      By:  PATRICK J. RETZER
                             Patrick J. Retzer
                             Senior Vice President