EXHIBIT 99.4

                  FOURTH AMENDMENT TO REVOLVING CREDIT FACILITY


     THIS FOURTH AMENDMENT, dated as of February 8, 2005 (this "Amendment"),  to
the REVOLVING  CREDIT  FACILITY,  dated as of January 14, 2003 and amended as of
February 5, 2003,  November 28, 2003 and  December 13, 2004 (as so amended,  the
"Agreement"),   between  NORTHWEST  AIRLINES,   INC.,  a  Minnesota  corporation
("Northwest"), and Pinnacle Airlines, Inc., a Georgia corporation ("Pinnacle");


                              W I T N E S S E T H:
                              --------------------

     WHEREAS, Northwest and Pinnacle are parties to the Agreement; and

     WHEREAS,  Pinnacle has requested that the Agreement be amended as set forth
herein;

     NOW THEREFORE,  in  consideration  of the premises and the mutual covenants
hereinafter set forth, the parties hereto hereby agree as follows:

     SECTION 1. Defined  Terms.  Terms  defined in the Agreement and used herein
shall have the meanings given to them in the Agreement.

     SECTION 2.  Amendment to Section 1. Section 1(a) of the Agreement is hereby
amended to read in its entirety as set forth below:

     "(a) June 30, 2005;"

     SECTION  3.  Amendment  to Section  13(a).  Clause (a) of Section 13 of the
Agreement is hereby amended to read in its entirety as set forth below:

     "(a)  Debt.  Create or suffer to exist any Debt,  except  (i) that  certain
promissory  note,  dated  November  28,  2003 and  payable  to our  order in the
original  principal  amount of  $135,000,000  (the "Dividend  Note");  provided,
however, that you hereby agree to cancel the Dividend Note immediately following
its  purchase  by  Guarantor  upon the  issuance  of  Guarantor's  3.25%  Senior
Convertible  Notes  due  2025  (the   "Convertible   Notes")  and  (ii)  a  cash
collateralized  line of credit  with  Union  Planters  Bank in an amount  not in
excess of  $1,000,000  at any time and used solely for the purpose of  obtaining
letters of credit from Union Planters Bank."

     SECTION  4.  Amendment  to Section  13(d).  Clause (d) of Section 13 of the
Agreement is hereby amended to read in its entirety as set forth below:



     "(d) Dividends, etc.. Declare or make any dividend or other distribution of
assets,  properties,  cash, rights,  obligations or securities on account of any
shares of your  classes of  capital  stock,  or  purchase,  redeem or  otherwise
acquire for value any shares of your classes of capital  stock or any  warrants,
rights or options to acquire  any such  shares,  now or  hereafter  outstanding;
provided,  however,  that  you may  declare  and  make  any  dividend  or  other
distribution of assets,  properties,  cash, rights, obligations or securities on
account of any shares of your classes of capital  stock,  or series of dividends
or  distributions  thereof,  to Guarantor in an aggregate  amount  sufficient to
enable  Guarantor  to  meet  its  financial  obligations   associated  with  the
Convertible  Notes and the issuance thereof which become due and payable between
the  date  of  issuance  of the  Convertible  Notes  and the  Termination  Date,
provided,  further,  that the sum of any such dividends or  distributions,  when
added to the sum of any outstanding loans and advances to Guarantor  pursuant to
Section  13(f)  hereof,  shall not at any time exceed  $5,000,000,  unless there
occurs a conversion event with respect to the Convertible  Notes which obligates
Guarantor to repay holders thereof all or part of their principal, provided that
upon such  conversion  event you agree that we shall have no  obligation to make
Loans hereunder in excess of the aggregate  amount that would have been drawn by
you in the ordinary course of business in the absence of such conversion event."

     SECTION 5. Effectiveness of this Amendment.

     This Amendment shall become  effective on the date on which Northwest shall
have  received  counterparts  of this  Amendment  duly executed and delivered by
Pinnacle and Guarantor.

     SECTION 6. Miscellaneous.

     (a) Effect. Except as expressly amended hereby, all of the representations,
warranties,  terms,  covenants  and  conditions  of the  Agreement  shall remain
unamended and not waived and shall continue to be in full force and effect.

     (b)  Counterparts.  This  Amendment  may be  executed by one or more of the
parties to this Amendment on any number of separate  counterparts  (including by
telecopy  transmission),  and all of said  counterparts  taken together shall be
deemed to constitute one and the same instrument.

     (c)  Severability.  Any provision of this Amendment  which is prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability  without  invalidating the
remaining provisions hereof, and any such prohibition or unenforceability in any
jurisdiction shall not invalidate or render  unenforceable such provision in any
other jurisdiction.

     (d)  Integration.  This  Amendment  represents the agreement of the parties
with  respect  to  the  subject  matter  hereof,  and  there  are  no  promises,

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undertakings,  representations  or  warranties  relative to the  subject  matter
hereof not expressly set forth or referred to herein.

     (e) GOVERNING  LAW. THIS  AMENDMENT AND THE RIGHTS AND  OBLIGATIONS  OF THE
PARTIES UNDER THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF MINNESOTA.

     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Amendment to be
duly executed and delivered by their proper and duly  authorized  officers as of
the day and year first above written.

                                NORTHWEST AIRLINES, INC.


                                By: /s/  Daniel B. Matthews
                                    ----------------------------------------
                                  Name:  Daniel B. Matthews
                                  Title: Senior Vice President & Treasurer


                                PINNACLE AIRLINES, INC.


                                By: /s/ Philip H. Trenary
                                    -------------------------------
                                  Name:   Philip H. Trenary
                                  Title:  President and CEO



                                GUARANTOR CONSENT

     The undersigned  Guarantor hereby acknowledges  receipt of a counterpart of
the foregoing Fourth Amendment to Revolving Credit Facility,  consents to all of
the terms and provisions  thereof and acknowledges and agrees that its Guaranty,
dated as of January 14, 2003,  in favor of Northwest  shall remain in full force
and effect after giving  effect to the foregoing  Fourth  Amendment to Revolving
Credit Facility.


                                PINNACLE AIRLINES CORP.


                                By: /s/ Philip H. Trenary
                                    -------------------------------
                                  Name:   Philip H. Trenary
                                  Title:  President and CEO


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