EXHIBIT 10.8.4


                ACKNOWLEDGMENT, CONSENT AND AGREEMENT (MSN 22237)

            ATLAS  AIR  WORLDWIDE   HOLDINGS,   INC.,  a  Delaware   corporation
("GUARANTOR"), with reference to the Guaranty, dated as of November 9, 2001 (the
"GUARANTY"),  made by  Guarantor  in favor of Polaris  Holding  Company  and its
successors  and assigns  ("GUARANTEED  PARTY")  relating to the  Aircraft  Lease
Agreement,  dated as of October 24, 2001,  between Polaris Holding  Company,  as
lessor,  and  Polar  Air  Cargo,  Inc.,  as  lessee,  as  supplemented  by Lease
Supplement  No. 1 dated  November  9, 2001 and the  Letter  Agreement  No. 1 (as
defined in such Aircraft Lease  Agreement),  and as assigned by Polaris  Holding
Company to Polaris  Aircraft  (Pacific Rim),  Inc.,  assumed by Polaris Aircraft
(Pacific Rim),  Inc. and amended  pursuant to the Aircraft Lease  Assignment and
Amendment  Agreement,  dated as of June 23, 2003, among Polaris Holding Company,
Polaris  Aircraft  (Pacific  Rim),  Inc.  ("LESSOR")  and Polar Air Cargo,  Inc.
("LESSEE")  (as so  supplemented  and as so assigned and  amended,  the "LEASE";
capitalized  terms used herein but not defined herein having the meanings stated
or ascribed in the Lease), and to the other Operative Documents, DOES HEREBY (in
each case, for the benefit of the Guaranteed  Party and, in each case (except to
the  extent  otherwise  provided  herein),  without  limitation  of any  term or
provision of the Guaranty):

                  (i)  ACKNOWLEDGE  receipt  (pursuant to and as required by the
      Guaranty)  of  notice  of (a)  the  amendment  of the  Lease  pursuant  to
      Amendment  Agreement  (MSN  22237),  dated as of August 1,  2003,  between
      Lessor and  Lessee  (the  "LEASE  AMENDMENT"),  and (b) the  Restructuring
      Letter Agreement (MSN 22237),  dated as of August 1, 2003,  between Lessor
      and Lessee which is referred to in the Lease Amendment (THE "RESTRUCTURING
      LETTER AGREEMENT");

                  (ii)  CONSENT  to (a) the  terms and  provisions  of the Lease
      Amendment  and the  Restructuring  Letter  Agreement,  (b) the  execution,
      delivery  and  performance  thereof  by  Lessor  and  Lessee,  and (c) the
      amendment of the Lease pursuant thereto and on the terms provided therein;

                  (iii)  AGREE  that,  from and  after  the  Effective  Date (as
      defined in the Lease  Amendment),  (a) any reference in the Guaranty,  the
      Lease or any other Operative Document,  or otherwise by Guarantor,  to the
      Lease shall mean the Lease, as amended by the Lease Amendment  (including,
      without  limitation,  the references  therein to the Restructuring  Letter
      Agreement),  and (b) any reference by Guarantor or Guaranteed Party to the
      Guaranty shall mean the Guaranty, as supplemented hereby; and

                  (iv) AGREE that, except as supplemented  hereby,  the Guaranty
      shall  remain in full force and effect as in  existence on the date hereof
      and is hereby ratified and confirmed in all respects.

                            [Signature Page Follows]



            IN  WITNESS  WHEREOF,  Guarantor  has  caused  this  Acknowledgment,
Consent  and  Agreement  to be  executed  and  delivered  as of this 18th day of
November, 2003.

                                         ATLAS AIR WORLDWIDE HOLDINGS, INC.


                                         By /s/ Jeffrey H. Erickson
                                            ------------------------------------
                                            Name: Jeffrey H. Erickson
                                            Title: President & COO


      [Signature Page to Acknowledgment, Consent and Agreement (MSN 22237)]