<PAGE>
                                                                    EXHIBIT 10.7

                        Prudential Capital Partners, L.P.
                Prudential Capital Partners Management Fund, L.P.
                       Four Embarcadero Center, Suite 2700
                          San Francisco, CA 94111-4180


                                                 November 12, 2003

Air Methods Corporation
ARCH Air Medical Service, Inc.
Mercy Air Service, Inc.
Rocky Mountain Holdings, L.L.C.
7301 South Peoria
Englewood, Colorado 80112

         Re:  Fourth Amendment/Waiver to Securities Purchase Agreement, dated
              as of October 16, 2002
              ---------------------------------------------------------------

Ladies and Gentlemen:

         Reference is made to the Securities Purchase Agreement, dated as of
October 16, 2002 (as amended, restated or supplemented from time to time, the
"PURCHASE AGREEMENT"), by and between Air Methods Corporation ("AIR METHODS"),
ARCH Air Medical Service, Inc., Mercy Air Service, Inc. and Rocky Mountain
Holdings, L.L.C. ("RMH") (collectively, the "CO-OBLIGORS"), on the one hand, and
Prudential Capital Partners, L.P. ("PCP") and Prudential Capital Partners
Management Fund, L.P. ("PCPMF", and together with PCP, the "PURCHASERS"), on the
other hand. Capitalized terms used and not otherwise defined herein shall have
the meanings provided in the Purchase Agreement.

         Pursuant to the request of the Co-Obligors and the provisions of
paragraph 12C of the Purchase Agreement, and subject to the terms and conditions
of this letter agreement, the Purchasers hereby: (i) waive the Event of Default
that resulted from the Co-Obligors' non-compliance during the fiscal quarter
ended September 30, 2003 with paragraph 7A(5) of the Purchase Agreement (Minimum
Consolidated EBITDA); and (ii) consent, notwithstanding anything to the contrary
in paragraph 7J of the Purchase Agreement, to the prepayment by any of the
Co-Obligors of Aircraft Indebtedness with the net proceeds of an offering of the
equity securities of Air Methods, but only if there is at least $10 million of
availability under the Senior Credit Facility at the time of any such
prepayment.

         Pursuant to the request of the Co-Obligors and the provisions of
paragraph 12C of the Purchase Agreement, and subject to the terms and conditions
of this letter agreement, the Purchasers hereby agree with the Co-Obligors that:

         1. Paragraph 4A(1) of the Purchase Agreement is hereby amended to (i)
delete the term "100%" set forth in the ninth line thereof and replace such term
with "106%", and (ii) delete the date "July 1, 2004" set forth in the last line
thereof and replace such date with "December 31, 2004".

         2. Paragraph 4A(2) of the Purchase Agreement is hereby amended to (i)
delete the date "July 1, 2004" set forth in the second line thereof and replace
such date with "December 31, 2004", and (ii) delete the reference to "7/1/2004"
set forth in the first line of the table set forth therein and replace such
reference with "12/31/2004".


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AIR METHODS CORPORATION
November 12, 2003
Page 2


         3. The caption and contents of paragraph 7A(5) are deleted in their
entirety and replaced with "INTENTIONALLY OMITTED".

         4. Each of Schedule 9D, 9R, 9Q and 9U is amended and restated in the
form set forth behind the Addendum to this letter agreement.

         Each of the waiver and amendments set forth in this letter agreement
shall be limited precisely as written and shall not be deemed to be (a) an
amendment, consent or waiver of any other terms or conditions of the Purchase
Agreement or any other document related to the Purchase Agreement or (b) a
consent to any future amendment, consent or waiver. Except as expressly set
forth in this letter, the Purchase Agreement and the documents related to the
Purchase Agreement shall continue in full force and effect.

         Each Co-Obligor hereby represents and warrants as follows (both before
and after giving effect to the effectiveness of this letter agreement): (i) No
Default or Event of Default has occurred and is continuing (or would result from
the transactions contemplated by this letter agreement) other than the Events of
Default as set forth hereinabove; (ii) such Co-Obligor's execution, delivery and
performance of the Purchase Agreement, as modified by this letter agreement,
have been duly authorized by all necessary corporate and other action and do not
and will not require any registration with, consent or approval of, or notice to
or action by, any Person (including any governmental authority) in order to be
effective and enforceable; (iii) the Purchase Agreement, as modified by this
letter agreement, constitutes the legal, valid and binding obligation of such
Co-Obligor, enforceable against such Co-Obligor in accordance with its terms
except as the enforceability thereof may be limited by bankruptcy, insolvency or
other similar laws of general application relating to or affecting the
enforcement of creditors' rights or by general principles of equity; and (iv)
each of the representations and warranties set forth in paragraph 9 of the
Purchase Agreement is true, correct and complete as of the date hereof after
giving effect to the amendment and restatement of each of Schedule 9D, 9R, 9Q
and 9U in the form set forth behind the Addendum to this letter agreement
(except to the extent such representations and warranties expressly relate to
another date, in which case such representations and warranties are true,
correct and complete as of such other date).

         The Co-Obligors agree to pay to the Purchasers on March 31, 2005 a
one-time fee to be shared ratably by each of the Purchasers (the "ONE-TIME FEE")
in the applicable amount set forth in the table below based on the applicable
amount of Consolidated EBITDA determined as of the fiscal year ended December
31, 2004; provided that, notwithstanding anything to the contrary in the
Purchase Agreement, including in the definition of "Consolidated EBITDA" or any
of the other definitions utilized in the definition of "Consolidated EBITDA",
Consolidated EBITDA measured as of December 31, 2004 for purpose of computing
the One-Time Fee shall not include operating results for Persons that become
Subsidiaries of Air Methods after the date hereof or for assets acquired after
the date hereof, other than acquisitions of equipment in the ordinary course of
the business of Air Methods and its Subsidiaries as conducted on the date
hereof:



<PAGE>

AIR METHODS CORPORATION
November 12, 2003
Page 3

<TABLE>
<CAPTION>
         Consolidated EBITDA as of 12/31/04                   Amount of One-Time Fee
         ----------------------------------                   ----------------------
         <S>                                                  <C>
            GREATER THAN $34,000,000                                       $0
            GREATER THAN $33,000,000 LESS THAN $34,000,000           $100,000
            GREATER THAN $32,000,000 LESS THAN $33,000,000           $200,000
            GREATER THAN $31,000,000 LESS THAN $32,000,000           $300,000
            GREATER THAN $30,000,000 LESS THAN $31,000,000           $400,000
            LESS THAN $30,000,000                                    $500,000
</TABLE>

For avoidance of doubt, the One-Time Fee shall be fully earned as of December
31, 2004 based on such computation of Consolidated EBITDA as of such date, and
shall be due and payable even if the Notes are prepaid on or after December 31,
2004 but prior to March 31, 2005. It shall be an immediate Event of Default
under the Purchase Agreement if the applicable amount of the One-Time Fee is not
received by the Purchasers on March 31, 2005.

         This letter agreement shall become effective on the date on which (i)
each of the Purchasers shall have received a fully executed counterpart of this
letter from each of the Co-Obligors and (ii) Bingham McCutchen LLP shall have
received from the Co-Obligors its accrued and unpaid legal fees and expenses.

         This document may be executed in multiple counterparts, which together
shall constitute a single document.

         If you are in agreement with the foregoing, please sign the enclosed
counterpart of this letter in the space indicated below and return it to the
Purchasers at the above address whereupon, subject to the conditions expressed
herein, it shall become a binding agreement between the Co-Obligors and the
Purchasers.

                                             Sincerely,

                                             PRUDENTIAL CAPITAL PARTNERS, L.P.

                                             By: Prudential Capital Group, L.P.,
                                             General Partner


                                             By: /s/ Stephen J. DeMartini
                                                --------------------------------
                                             Its:  Vice President


                                             PRUDENTIAL CAPITAL PARTNERS,
                                             MANAGEMENT FUND, L.P.

                                             By: Prudential Investment
                                             Management, Inc., General Partner


                                             By: /s/ Stephen J. DeMartini
                                                --------------------------------
                                             Its:  Vice President


<PAGE>


AIR METHODS CORPORATION
November 12, 2003
Page 4


Accepted and agreed to as of the date first appearing above:

AIR METHODS CORPORATION

By: /s/ Trent J. Carman
    ----------------------------------------
Its: Chief Financial Officer


ARCH AIR MEDICAL SERVICE, INC.

By: /s/ Trent J. Carman
    ----------------------------------------
Its: Chief Financial Officer



MERCY AIR SERVICE, INC.

By: /s/ Trent J. Carman
    ----------------------------------------
Its: Chief Financial Officer



ROCKY MOUNTAIN HOLDINGS, L.L.C.

By: /s/ Trent J. Carman
    ----------------------------------------
Its: Chief Financial Officer