Exhibit 10.9.4










Exhibit 10.9.4




SIXTH
MODIFICATION AGREEMENT






BY THIS
SIXTH MODIFICATION AGREEMENT (the "Agreement"), made and entered into as of the
13th day of May, 2004, WELLS FARGO BANK, NATIONAL ASSOCIATION, as administrative
agent (the "Administrative Agent") for the Banks listed in the hereinafter
defined Credit Agreement (the "Banks") and as the Issuing Bank and the Swing
Line Lender, and KNIGHT TRANSPORTATION, INC., an Arizona corporation (the
"Company") and all present and future Significant Subsidiaries of the Company
(with the Company, the "Borrower"), in consideration of the mutual covenants
herein contained and other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, hereby confirm and agree as
follows:




SECTION
1.     RECITALS;
ACKNOWLEDGEMENTS.




1.1     The
Borrower and the Administrative Agent and the Banks entered into that Credit
Agreement dated April 6, 2001 (as amended from time to time, the "Credit
Agreement") to provide financial accommodations to the Borrower as provided
therein. The Credit Agreement was previously amended by that Modification
Agreement dated as of June 5, 2001, that Second Modification Agreement dated as
of November 19, 2001, that Third Modification Agreement dated as of February 13,
2003, that Fourth Modification Agreement dated as of September 15, 2003 and that
Fifth Modification Agreement dated as of December 15, 2003.

 


1.2     Borrower
and the Administrative Agent, with the consent of the Banks, desire to modify
the Credit Agreement as set forth herein.




1.3     All
undefined capitalized terms used herein shall have the meaning given them in the
Credit Agreement.



SECTION
2.    CREDIT
AGREEMENT.

 


2.1     The following
definitions in Section 1.1 of the Credit Agreement are hereby amended to read as
follows:




    "Letter of
Credit Commitment" shall mean $11,000,000.00.




    "Maximum RLC
Commitment" shall mean $11,000,000.00.




2.2     Schedule
2.1 of the Credit Agreement is hereby amended to read as attached
hereto.




2.3     All
references in the Note to "10,000,000.00" or to "Ten Million and NO/100 Dollars"
are hereby amended to read "11,000,000.00" and "Eleven Million and NO/100
Dollars," respectively.





SECTION
3.     OTHER
MODIFICATIONS, RATIFICATIONS AND AGREEMENTS.




3.1     All
references to the Credit Agreement in the other Loan Documents are hereby
amended to refer to the Credit Agreement as hereby amended.























3.2     Borrower
hereby reaffirms to the Banks each of the representations, warranties, covenants
and agreements of Borrower set forth in the Credit Agreement, with the same
force and effect as if each were separately stated herein and made as of the
date hereof.




3.3     Borrower
hereby ratifies, reaffirms, acknowledges, and agrees that the Notes and the
Credit Agreement represent valid, enforceable and collectible obligations of
Borrower, and that there are no existing claims, defenses, personal or
otherwise, or rights of setoff whatsoever with respect to any of these documents
or instruments. Borrower further acknowledges and represents that no event has
occurred and no condition exists that, after notice or lapse of time, or both,
would constitute a default under this Agreement, the Notes or the Credit
Agreement.




3.4     All terms,
conditions and provisions of the Credit Agreement are continued in full force
and effect and shall remain unaffected and unchanged except as specifically
amended hereby. The Credit Agreement, as amended hereby, is hereby ratified and
reaffirmed by Borrower, and Borrower specifically acknowledges the validity and
enforceability thereof.



SECTION
4.     GENERAL.


 

4.1     This
Agreement in no way acts as a release or relinquishment of those rights securing
payment of the Loans. Such rights are hereby ratified, confirmed, renewed and
extended by Borrower in all respects.




4.2     The
modifications contained herein shall not be binding upon the Banks until the
Administrative Agent shall have received all of the following:





	 	
      (a)
	
      An
      original of this Agreement fully executed by the
  Borrower.








	 	
      (b)
	
      Such
      resolutions or authorizations and such other documents as the
      Administrative Agent may require relating to the existence and good
      standing of the Borrower and the authority of any person executing this
      Agreement or other documents on behalf of the
Borrower.







4.3     Borrower
shall execute and deliver such additional documents and do such other acts as
the Banks may reasonably require to fully implement the intent of this
Agreement.




4.4     Borrower
shall pay all costs and expenses, including, but not limited to, reasonable
attorneys' fees incurred by the Administrative Agent in connection herewith,
whether or not all of the conditions described in Paragraph 4.2 above are
satisfied. Banks, at their option, but without any obligation to do so, may
advance funds to pay any such costs and expenses that are the obligation of the
Borrower, and all such funds advanced shall bear interest at the highest rate
provided in the Notes and shall be due and payable upon demand.




4.5     Notwithstanding
anything to the contrary contained herein or in any other instrument executed by
Borrower, the Administrative Agent or the Banks, or in any other action or
conduct undertaken by Borrower, the Administrative Agent or the Banks on or
before the date hereof, the agreements, covenants and provisions contained
herein shall constitute the only evidence of the Banks' consent to modify the
terms and provisions of the Credit Agreement. Accordingly, no 











2













express
or implied consent to any further modifications involving any of the matters set
forth in this Agreement or otherwise shall be inferred or implied by the Banks'
consent to this Agreement. Further, the Banks' consent to this Agreement shall
not constitute a waiver (either express or implied) of the requirement that any
further modification of the Credit Agreement shall require the express written
consent of the Bank; no such consent (either express or implied) has been given
as of the date hereof.




4.6     Time is
hereby declared to be of the essence hereof of the Credit Agreement, and Banks
require, and Borrower agrees to, strict performance of each and every covenant,
condition, provision and agreement hereof, of the Credit Agreement.




4.7     This
Agreement shall be binding upon, and shall inure to the benefit of, the parties
hereto and their heirs, personal representatives, successors and
assigns.




4.8     This
Agreement is made for the sole protection and benefit of the parties hereto, and
no other person or entity shall have any right of action hereon.




4.9     This
Agreement shall be governed by and construed according to the laws of the State
of Arizona.







    IN WITNESS
WHEREOF, these presents are executed as of the date indicated
above.





	 	
      WELLS
      FARGO BANK, NATIONAL ASSOCIATION

	 	
       

       

      By:
      
	
       

       

      /s/
      Keri Tignini

	 	
      Name:
	
      Keri
      Tignini

	 	
      Its:
	
      Vice
      President

	 	 
	 	 	
      ADMINISTRATIVE
      AGENT

	 	 
	 	
      KNIGHT
      TRANSPORTATION, INC.

	 	
       

       

      By:
      
	
       

       

      /s/
      Tim Kohl

	 	
      Name:
	
      Tim
      Kohl

	 	
      Its:
	
      Treasurer

	 	 
	 	
      QUAD-K
      LEASING, INC., an Arizona corporation

	 	
       

       

      By:
      
	
       

       

      /s/
      Tim Kohl

	 	
      Name:
	
      Tim
      Kohl

	 	
      Its:
	
      President

	 	 
	 	 	
      BORROWER

	 	 	 
	 	 	 












3












CONSENT
OF THE BANKS 







Re: Knight
Transportation, Inc.




The
following:




(a)     is a Bank
named in that Credit Agreement dated April 6, 2001 between Knight
Transportation, Inc., an Arizona corporation (the "Company"), all present and
future Significant Subsidiaries of the Company (the "Borrower"), Wells Fargo
Bank, National Association, as administrative agent for the Banks (the
"Administrative Agent"), and the Banks; and




(b)     consents
to that Sixth Modification Agreement dated May 13,
2004
entered into between the Borrower and the Administrative Agent.





	 	
      WELLS
      FARGO BANK, NATIONAL ASSOCIATION

	 	
       

       

      By:
      
	
       

       

      /s/
      Keri Tignini

	 	
      Name:
	
      Keri
      Tignini

	 	
      Its:
	
      Vice
      President

	 	 
	 	 	
      "Bank"



































SCHEDULE
2.1




COMMITMENTS
OF BANKS

as to the
Facility

as of
___________, 2004





	 	 	
                      
      Bank
	 	% 	 	
      $
	 
	 	 	 	 	 	 	 	 
	1.
	 	 	
      Wells
      Fargo Bank,

      National
      Association
	 	 	
      100%
	 
	 
	
      $11,000,000.00
	 
	 

       
	 	 	
       

      Maximum
      RLC

      Commitment 
	 	 	
      100%
	 
	 
	
      $11,000,000.00
	 









Addresses:





	
      1.
	
      100
      West Washington 

      Commercial
      Banking 

      MAC
      S4101-251 

      Phoenix,
      Arizona 85003 

      Attention:
      Keri Tignini 

      Phone:
      602-378-4593 

      Fax:
      602-378-4758