Document:

Exhibit 10.3.5

                                                                  EXECUTION COPY

                               AMENDMENT NO. 4 TO
                           LOAN AND SECURITY AGREEMENT

      AMENDMENT  NO. 4 TO LOAN AND  SECURITY  AGREEMENT,  dated as of March  30,
2006,  entered  into  by and  among  Wachovia  Bank,  National  Association,  as
successor  by merger to  Congress  Financial  Corporation,  a  national  banking
association, in its capacity as agent acting for and on behalf of the parties to
the Loan  Agreement  (as  hereinafter  defined)  as lenders  (in such  capacity,
"Agent"),  the parties to the Loan  Agreement as lenders  (each  individually  a
"Lender" and collectively,  "Lenders"),  Atlas Air, Inc., a Delaware corporation
("Atlas Air"), Polar Air Cargo,  Inc., a California  corporation  ("Polar",  and
together  with Atlas Air,  each  individually,  a "Borrower"  and  collectively,
"Borrowers"), Atlas Air Worldwide Holdings, Inc., a Delaware corporation ("Atlas
Holdings") and Airline Acquisition Corp I, a Delaware  corporation  ("AACI", and
together with  Holdings,  each  individually,  a "Guarantor"  and  collectively,
"Guarantors").

                              W I T N E S S E T H:

      WHEREAS,  Agent,  Lenders,  Borrowers  and  Guarantors  have  entered into
financing arrangements pursuant to which Lenders (or Agent on behalf of Lenders)
have  made  and  may  make  loans  and  advances  and  provide  other  financial
accommodations  to Borrowers  as set forth in the Loan and  Security  Agreement,
dated November 30, 2004, by and among Agent,  Lenders,  Borrowers and Guarantors
as amended by Amendment  No. 1 to Loan and Security  Agreement,  dated as of May
31, 2005,  Amendment No. 2 to Loan and Security Agreement,  dated July 25, 2005,
by and among Agent,  Lenders,  Borrowers and  Guarantors  and Amendment No. 3 to
Loan and Security Agreement,  Consent and Waiver, dated as of October,  2005 and
as  further  amended  hereby  (as the same may  hereafter  be  further  amended,
modified,  supplemented,  extended,  renewed,  restated or  replaced,  the "Loan
Agreement",  and together with all agreements,  documents and instruments at any
time executed and/or delivered in connection  therewith or related  thereto,  as
from time to time amended, modified, supplemented,  extended, renewed, restated,
or replaced, collectively, the "Financing Agreements");

      WHEREAS,  Borrowers and  Guarantors  have requested that Agent and Lenders
agree to certain  amendments  to the Loan  Agreement  and Agent and  Lenders are
willing to so agree, subject to the terms and conditions contained herein; and

      WHEREAS, by this Amendment No. 4, Agent, Lenders, Borrowers and Guarantors
desire and intend to evidence such amendments;

      NOW, THEREFORE,  in consideration of the foregoing,  the mutual agreements
and covenants contained herein, and other good and valuable  consideration,  the
receipt and  sufficiency  of which are hereby  acknowledged,  the parties hereto
agree as follows:

      1. DEFINITIONS.

            (a) ADDITIONAL DEFINITION.  As used herein, the following term shall
have  the  meaning  given to it  below,  and the Loan  Agreement  and the  other
Financing  Agreements  are hereby  amended to include,  in  addition  and not in
limitation, the following definition:

<PAGE>

                  "AMENDMENT  NO. 4" shall mean this Amendment No. 4 to Loan and
                  Security Agreement by and among Agent, Lenders,  Borrowers and
                  Guarantors,  as  the  same  now  exists  or may  hereafter  be
                  amended, modified,  supplemented,  extended, renewed, restated
                  or replaced.

            (b)  INTERPRETATION.  For purposes of this  Amendment  No. 4, unless
otherwise defined herein, all capitalized terms used herein which are defined in
the Loan  Agreement  shall  have the  meanings  given to such  terms in the Loan
Agreement.

      2. FINANCIAL  STATEMENTS AND OTHER INFORMATION.  Section 9.6(a)(ii) of the
Loan  Agreement is hereby  amended by deleting the reference  therein to "ninety
(90) days" and substituting "one hundred twenty (120) days" therefor.

      3.  REPRESENTATIONS,   WARRANTIES  AND  COVENANTS.   In  addition  to  the
continuing  representations,  warranties  and covenants  heretofore or hereafter
made by  Borrowers  and  Guarantors  to Agent and Lenders  pursuant to the other
Financing Agreements,  each of Borrowers and Guarantors,  jointly and severally,
hereby  represents,  warrants  and  covenants  with and to Agent and  Lenders as
follows  (which  representations,  warranties  and covenants are  continuing and
shall survive the execution and delivery hereof and shall be  incorporated  into
and made a part of the Financing Agreements):

            (a) This  Amendment  No. 4 has been duly  authorized,  executed  and
delivered by all  necessary  corporate  action on the part of each  Borrower and
Guarantor  which is a party  hereto,  and is in full  force and effect as of the
date hereof,  and the  agreements  and  obligations  of Borrowers and Guarantors
contained herein  constitute legal,  valid and binding  obligations of Borrowers
and Guarantors enforceable against them in accordance with their terms.

            (b) All of the  representations and warranties set forth in the Loan
Agreement and the other Financing  Agreements,  each as amended hereby, are true
and correct in all material  respects on and as of the date hereof as if made on
the date  hereof,  except to the extent any such  representation  or warranty is
made as of a specified date, in which case such representation or warranty shall
have  been  true  and  correct  in  all  material  respects  as  of  such  date.
Notwithstanding the foregoing, the Agent, on behalf of the Lenders, acknowledges
that Polar received a formal request for information in connection with the U.S.
Government's    investigation    into   air   cargo   pricing   practices   (the
"Investigation")  and  that,  while  the  Investigation  has not had,  and Atlas
Holdings does not expect the  Investigation  to have, a Material Adverse Effect,
the Agent, on behalf of the Lenders,  agrees that the  representation in Section
8.6 of the Loan  Agreement  shall be deemed to be  qualified by reference to the
Investigation for purposes of this Amendment No. 4.

            (c) No  Default or Event of Default  exists or has  occurred  and is
continuing.

            (d) All necessary actions and proceedings  required by the Financing
Agreements in connection with this Amendment No. 2, applicable law or regulation
and the  transactions  contemplated  thereby have been duly and validly taken in
accordance with the terms thereof,  and all required  consents thereto under any
agreement, document or instrument to which Borrowers and Guarantors are a party,
and all applicable consents or approvals of governmental authorities,  have been
obtained.

                                       2
<PAGE>

      4. CONDITIONS  PRECEDENT.  The  effectiveness of the amendments  contained
herein shall only be effective  upon the  satisfaction  of each of the following
conditions precedent in a manner satisfactory to Agent:

            (a) Agent shall have received, as of the date hereof, this Amendment
No. 4 duly authorized, executed and delivered by the parties hereto, and

            (b) no Default or Event of Default shall exist or have occurred.

      5. EFFECT OF THIS  AMENDMENT.  This Amendment No. 4 constitutes the entire
agreement of the parties with respect to the subject  matter hereof and thereof,
and supersedes all prior oral or written communications,  memoranda,  proposals,
negotiations,  discussions,  term  sheets and  commitments  with  respect to the
subject matter hereof and thereof.  Except as expressly  amended pursuant hereto
and except for the amendments  expressly  contained  herein, no other changes or
modifications  or waivers to the Financing  Agreements  are intended or implied,
and in all other  respects  the  Financing  Agreements  are hereby  specifically
ratified,  restated and confirmed by all parties hereto as of the effective date
hereof.  To the extent that any  provision  of the Loan  Agreement or any of the
other  Financing  Agreements  are  inconsistent  with  the  provisions  of  this
Amendment No. 4, the provisions of this Amendment No. 4 shall control.

      6.  GOVERNING  LAW.  The rights and  obligations  hereunder of each of the
parties hereto shall be governed by and interpreted and determined in accordance
with the internal laws of the State of New York (but excluding any principles of
conflicts  of law or other rule of law that would cause the  application  of the
law of any jurisdiction other than the laws of the State of New York).

      7. BINDING EFFECT. This Amendment No. 4 shall be binding upon and inure to
the benefit of each of the parties  hereto and their  respective  successors and
assigns.

      8.  COUNTERPARTS.  This  Amendment  No. 4 may be executed in any number of
counterparts, but all of such counterparts shall together constitute but one and
the same  agreement.  In making proof of this  Amendment  No. 4, it shall not be
necessary to produce or account for more than one counterpart  thereof signed by
each  of the  parties  hereto.  Delivery  of an  executed  counterpart  of  this
Amendment No. 4 by  telecopier  shall have the same force and effect as delivery
of an  original  executed  counterpart  of  this  Amendment  No.  4.  Any  party
delivering an executed  counterpart of this  Amendment No. 4 by telecopier  also
shall deliver an original executed  counterpart of this Amendment No. 4, but the
failure  to  deliver  an  original  executed  counterpart  shall not  affect the
validity,  enforceability, and binding effect of this Amendment No. 4 as to such
party or any other party.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       3
<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 4 to
be duly executed and delivered by their authorized officers as of the day and
year first above written.

                                           BORROWERS

                                           ATLAS AIR, INC.

                                           By: /s/ Dorinda Pannozzo
                                               ---------------------------------
                                           Title: Staff Vice President
                                                  Assistant Treasurer
                                                  ------------------------------

                                           POLAR AIR CARGO, INC.

                                           By: /s/ Dorinda Pannozzo
                                               ---------------------------------
                                           Title: Staff Vice President
                                                  Assistant Treasurer
                                                  ------------------------------

                                           GUARANTORS

                                           ATLAS AIR WORLDWIDE
                                           HOLDINGS, INC.

                                           By: /s/ William C. Bradley
                                               ---------------------------------
                                           Title: Vice President & Treasurer
                                                  ------------------------------

                                           AIRLINE ACQUISITION CORP I

                                           By: /s/ William C. Bradley
                                               ---------------------------------
                                           Title: Vice President & Treasurer
                                                  ------------------------------

AGREED:

WACHOVIA BANK, NATIONAL ASSOCIATION,
as successor by merger to Congress Financial Corporation,
as Agent and Lender

By: /s/ Dave Luce
    --------------------
Title: VICE PRESIDENT
       -----------------Exhibit 10.5.4

                          CONSENT AND SECOND AMENDMENT

      CONSENT  AND SECOND  AMENDMENT  (this  "AMENDMENT"),  dated as of July 28,
2005,  among  ATLAS  AIR  WORLDWIDE  HOLDINGS,   INC.,  a  Delaware  corporation
("HOLDINGS"),  ATLAS AIR, INC., a Delaware corporation ("COMPANY"),  the lenders
from  time to time  party to the  Credit  Agreement  referred  to below  (each a
"LENDER"  and,  collectively,  the  "LENDERS"),  and DEUTSCHE BANK TRUST COMPANY
AMERICAS,  as  Administrative  Agent for the  Lenders,  (in such  capacity,  the
"ADMINISTRATIVE  AGENT"). Unless otherwise defined herein, all capitalized terms
used  herein  and  defined in the Credit  Agreement  referred  to below are used
herein as therein defined.

                              W I T N E S S E T H:

      WHEREAS, Holdings,  Company, the Lenders and the Administrative Agent have
entered into a Fifth Amended and Restated Credit Agreement, dated as of July 27,
2004 (as amended,  supplemented  or otherwise  modified  from time to time,  the
"CREDIT AGREEMENT"); and

      WHEREAS,  Holdings and Company have  requested  that the Lenders amend the
Credit Agreement and enter into a consent in respect of the Credit Agreement and
the Aircraft Chattel Mortgages as set forth below;

      NOW, THEREFORE, it is agreed;

A.    AMENDMENT TO THE CREDIT AGREEMENT

      1. The definition of "AFL III  Equipment"  appearing in Section 1.1 of the
Credit Agreement is hereby amended by (x) deleting the text "thirteen" appearing
therein and (y) inserting the text "twelve" in lieu thereof; by (z) deleting the
text ", N808MC" contained therein.

B.    CONSENT

      1. The Lenders  hereby  consent to amend  Section  4(g)(ii) of each of the
Aircraft  Chattel  Mortgages  to reduce the minimum  required  insured  value in
respect of each Financed Aircraft to an amount not less than $15,000,000.

C.    MISCELLANEOUS PROVISIONS

      1. In order to induce the Lenders to enter into this  Amendment,  Holdings
and Company hereby  represent and warrant to each of the Lenders that (i) all of
the representations and warranties  contained in the Credit Agreement and in the
other Loan Documents are true and correct in all material respects on the Second
Amendment Effective Date (as defined below), both before and after giving effect
to this  Amendment  (unless  such  representations  and  warranties  relate to a
specific earlier date, in which case such  representations  and warranties shall
be true and correct as of such earlier  date),  and (ii) there exists no Default
or Event of

<PAGE>

Default on the Second  Amendment  Effective  Date,  both before and after giving
effect to this Amendment.

      2. This  Amendment is limited as  specified  and shall not  constitute  an
amendment,  modification,  acceptance  or waiver of any other  provision  of the
Credit Agreement or any other Loan Document.

      3. This Amendment may be executed in any number of counterparts and by the
different parties hereto on separate  counterparts,  each of which  counterparts
when  executed  and  delivered  shall be an  original,  but all of  which  shall
together constitute one and the same instrument.  A complete set of counterparts
executed  by all the  parties  hereto  shall  be  lodged  with  Company  and the
Administrative Agent.

      4. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES  HEREUNDER
SHALL BE  CONSTRUED IN  ACCORDANCE  WITH AND GOVERNED BY THE LAW OF THE STATE OF
NEW YORK.

      5.  This  Amendment  shall  become  effective  on the  date  (the  "SECOND
AMENDMENT EFFECTIVE DATE") when Holdings, Company and the Required Lenders shall
have signed a counterpart  hereof  (whether the same or different  counterparts)
and  shall  have  delivered  (including  by way of  telecopier)  the same to the
Administrative Agent.

      6. From and after Second  Amendment  Effective Date, all references in the
Credit  Agreement and in the other Loan Documents to the Credit  Agreement shall
be deemed to be referenced to the Credit Agreement as modified hereby.

                                      * * *

                                      -2-
<PAGE>

      IN WITNESS WHEREOF,  the undersigned have caused this Amendment to be duly
executed and delivered as of the date first above written.

                                              ATLAS AIR WORLDWIDE HOLDINGS, INC.

                                              By: /s/ Dorinda Pannozzo
                                                  ------------------------------
                                                  Name:
                                                  Title:

                                              ATLAS AIR, INC.

                                              By: /s/ Dorinda Pannozzo
                                                  ------------------------------
                                                  Name:
                                                  Title:

<PAGE>

                                    DEUTSCHE BANK TRUST COMPANY
                                    AMERICAS, Individually and as Administrative
                                    Agent

                                    By: /s/ David J. Bell
                                        ----------------------------------------
                                        Name:  David J. Bell
                                        Title: Managing Director

                                    By: /s/ Robert M. Wood, Jr.
                                        ----------------------------------------
                                        Name:  Robert M. Wood, Jr.
                                        Title: Director

<PAGE>

                                      NAME OF LENDER:

                                      Canpartners Investments IV, LLC

                                      By: /s/ Mitchell R. Julis
                                          --------------------------------------
                                          Mitchell R. Julis
                                          Managing Director

                                      By: Canpartners Investment IV, LLC,
                                          a California limited liability company

PROPORTIONATE VOTING PROVISIONS

The above signed,  Canpartners  Investments IV, LLC  ("Canyon"),  is a Lender to
Atlas Air, dated as of July 27, 2004 (the "Credit Agreement"). Canyon's approval
of a Consent  and Second  Amendment  to the Fifth  Amended and  Restated  Credit
Agreement has been requested pursuant to the terms of the Credit Agreement.

Canyon  hereby  votes  its  percentage  interest  as a Lender in favor of and/or
against the approval of the Consent and Second  Amendment  to the Fifth Amended
and Restated Credit  Agreement in direct  proportion to the votes of those other
Lenders under the Credit  Agreement  that have voted for or against the approval
of the Consent and Second  Amendment to the Fifth  Amended and  Restated  Credit
Agreement (without counting failure to vote or abstentions.)

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      FERNWOOD RESTRUCTURINGS LIMITED

                                      By: /s/ Robert Gaviglio
                                          --------------------------------------
                                          Name:  Robert Gaviglio
                                          Title: VP

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      FERNWOOD FOUNDATION FUND LLC

                                      By: /s/ Robert Gaviglio
                                          --------------------------------------
                                          Name:  Robert Gaviglio
                                          Title: VP

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      FERNWOOD ASSOCIATES LLC

                                      By: /s/ Robert Gaviglio
                                          --------------------------------------
                                          Name:  Robert Gaviglio
                                          Title: VP

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      Sankaty Advisors, LLC as Collateral
                                      Manager for Prospect Funding I,
                                      LLC as Term Lender

                                      NAME OF LENDER:

                                      ___________________________

                                      By: /s/ Diane J. Exter
                                          --------------------------------------
                                          Name:  Diane J. Exter
                                          Title: MANAGING DIRECTOR
                                                 PORTFOLIO MANAGER

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      Restoration Holdings Ltd.

                                      By: /s/ Pamela M. Lawrence
                                          --------------------------------------
                                          Name:  Pamela M. Lawrence
                                          Title: Director

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      __________________________

                                      By: /s/ Suzanne Kelcher
                                          --------------------------------------
                                          Name:  Suzanne Kelcher
                                          Title: Attorney-In-Fact
                                                 Royal Bank of Canada

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      Sankaty High Yield Asset Partners, L.P.

                                      By: /s/ Diane J. Exter
                                          --------------------------------------
                                          Name:  Diane J. Exter
                                          Title: MANAGING DIRECTOR
                                                 PORTFOLIO MANAGER

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      Sankaty High Yield Asset Partners II, L.P.

                                      By: /s/ Diane J. Exter
                                          --------------------------------------
                                          Name:  Diane J. Exter
                                          Title: MANAGING DIRECTOR
                                                 PORTFOLIO MANAGER

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                     NAME OF LENDER:

                                     Sankaty High Yield Asset Partners III, L.P.

                                     By: /s/ Diane J. Exter
                                         ---------------------------------------
                                         Name:  Diane J. Exter
                                         Title: MANAGING DIRECTOR
                                                PORTFOLIO MANAGER

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

<PAGE>

                                      NAME OF LENDER:

                                      U.S. BANK NATIONAL ASSOCIATION

                                      By: /s/ Dale L. Welke
                                          --------------------------------------
                                          Name:  Dale L. Welke
                                          Title: Vice President

              [Signature Page to the Consent and Second Amendment
              to the Fifth Amended and Restated Credit Agreement]

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