Document:

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                                                                     EXHIBIT 4.4

                             SUBORDINATION AGREEMENT

        THIS SUBORDINATION AGREEMENT dated as of December 31, 1999 (this
"Agreement") is among BANK ONE, MICHIGAN, a Michigan banking corporation,
formerly known as NBD Bank, as agent (in such capacity, the "Agent") for the
Senior Lenders (as defined below), AIRNET MANAGEMENT, INC., an Ohio corporation
(the "Subordinated Lender"), and AIRNET SYSTEMS, INC., an Ohio corporation (the
"Company").

                                   BACKGROUND

        As an inducement for the Senior Lenders to continue to provide a credit
facility in favor of the Company, the Subordinated Lender has agreed to enter
into this subordination agreement to provide for the subordination of the
"Subordinated Indebtedness" to the "Senior Indebtedness", all on the terms and
conditions herein set forth.

                                   AGREEMENTS

        NOW, THEREFORE, for good and valuable consideration, receipt of which is
hereby acknowledged, the parties hereto agree as follows:

               1.     Definitions.

                      1.1    General Terms.  For purposes of this Agreement, the
following terms shall have the following respective meanings:

                      "Agreements" means, collectively, the Senior Lending
Agreements and the Subordinated Lending Agreements.

                     "Credit Agreement" means the Credit Agreement, dated as of
August 1, 1998, among the Company, the Senior Lenders and the Agent, as amended
by the First Amendment to Credit Agreement dated as of September 30, 1998 and as
further amended by the Second Amendment to Credit Agreement dated of even date
herewith, as further amended, supplemented, extended, modified, renewed,
restated, restructured, refinanced or replaced from time to time, and including
without limitation any agreement entered into in substitution therefor or
increasing the amount of available borrowings thereunder.

                     "Creditors" means, collectively, Senior Lenders and
Subordinated Lenders and their respective successors and assigns.

                     "Distribution" means any payment, whether in cash, in kind,
in securities or in any other property, or security therefor.

                     "Guarantor" means any Person at any time guaranteeing or
otherwise contingently liable for or otherwise supporting (including without
limitation any Person granting a Lien on any of its assets) the Senior
Indebtedness or the Subordinated Indebtedness.

                     "Holders of Subordinated Indebtedness" or "Subordinated
Lenders" means, collectively, the Subordinated Lender and any other Persons at
any time or in any manner acquiring any right to or interest in any of the
Subordinated Indebtedness.

                     "Insolvency Event" shall have the meaning set forth in
Section 2.2(c) hereof.

                     "Lien" means any pledge, assignment, hypothecation,
mortgage, deed of trust, security interest, deposit arrangement, option,
conditional sale or title retaining contract, sale and lease back transaction,
financing statement filing, intellectual property transfer or assignment filing,
lessor's or lessee's interest under any lease, subordination of any claim or
right, or any other type of lien, charge, assignment, encumbrance, preferential
arrangement or other claim or right.

                     "Obligations" means all present and future obligations for
principal, premium, interest, make whole payments, penalties, fees,
indemnifications, reimbursements, damages and other liabilities and obligations
under any of the Agreements and other documentation governing or relating to the
Senior Indebtedness or the Subordinated Indebtedness or otherwise owing pursuant
to the Senior Indebtedness or the Subordinated Indebtedness at any time.

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                     "Obligors" means, collectively, the Company and the
Guarantors.

                     "Payment Default" is defined in Section 2.2(d).

                     "Person" means an individual, a partnership, a corporation
(including a business trust), a joint stock company, a trust, an unincorporated
association, a joint venture, a limited liability company, a limited liability
partnership or other entity, or a government or any agency, instrumentality or
political subdivision thereof.

                     "Senior Indebtedness" means all present and future
indebtedness, obligations and liabilities of any kind owing by the Company, any
Guarantor or any other Person to Senior Lenders or any of them from time to time
under or pursuant to any of the Senior Lending Agreements, including, without
limitation, all principal, interest accruing thereon, reimbursement and other
Obligations owing pursuant to any letters of credit or similar documents,
indemnities, charges, expenses, fees and other Obligations chargeable to the
Company, any Guarantor or any such other Person by Senior Lenders or any of them
or otherwise due and payable at any time to the Senior Lenders or any of them,
(including without limitation all interest and fees and other amounts accruing
after commencement of any case, proceeding or other action relating to the
bankruptcy, insolvency or reorganization of the Company or any other Obligor,
whether or not an allowed claim). Senior Indebtedness shall continue to
constitute Senior Indebtedness, notwithstanding the fact that such Senior
Indebtedness or any claim for such Senior Indebtedness is subordinated, avoided
or disallowed under the federal Bankruptcy Code or other applicable law. Without
limiting the foregoing, Senior Indebtedness shall also include any indebtedness,
obligations and liabilities of the Company, any Guarantor or any such other
Person incurred in connection with a refinancing of the Senior Indebtedness.

                     "Senior Lenders" means the Agent and all lenders now or
hereafter parties to the Credit Agreement and any other Persons at any time or
in any manner acquiring any right to or interest in any of the Senior
Indebtedness.

                     "Senior Lending Agreements" means, collectively, the Credit
Agreement (as defined in this Agreement), and all promissory notes, guarantees,
pledge agreements, security agreements, mortgages, financing statements and
other agreements, instruments and documents from time to time entered into by
the Company, any Guarantor or any other Person to evidence, secure, guarantee or
otherwise relating in any way to, or executed in connection with, the Senior
Indebtedness, and all agreements, devices or arrangements providing for payments
which are relating to fluctuations of interest rates, exchange rates or forward
rates (including without limitation any interest rate, swap agreements, dollar
denominated or cross currency interest rate exchange agreements, forward
currency exchange agreements, interest rate cap or collar protection agreements,
forward rate currency or interest rate options, puts and warrants) entered into
by the Company with any Senior Lender or Affiliate of any Senior Lender at any
time, as all of the foregoing may be amended, modified, supplemented, extended,
renewed, restated or replaced from time to time.

                     "Subordinated Indebtedness" means all present and future
indebtedness, obligations and liabilities of any kind owing by the Company, any
Guarantor or any other Person to Subordinated Lenders or any of them from time
to time under or pursuant to any of the Subordinated Lending Agreements,
including, without limitation, all principal, interest accruing thereon,
reimbursement and other Obligations owing pursuant to any letters of credit or
similar documents, indemnities, charges, expenses, fees and other Obligations
chargeable to the Company, any Guarantor or any such other Person by
Subordinated Lenders or any of them or otherwise due and payable at any time to
the Subordinated Lenders or any of them, (including without limitation all
interest and fees and other amounts accruing after commencement of any case,
proceeding or other action relating to the bankruptcy, insolvency or
reorganization of the Company or any other Obligor, whether or not an allowed
claim). Without limiting the foregoing, Subordinated Indebtedness shall also
include any indebtedness, obligations and liabilities of the Company, any
Guarantor or any such other Person incurred in connection with a refinancing of
the Subordinated Indebtedness.

                     "Subordinated Lending Agreements" means, collectively, the
Subordinated Note and all guarantees, and other agreements, instruments and
documents from time to time entered into by the Company, any Guarantor or any
other Person to evidence, secure, guarantee or otherwise relating in any way to,
or executed in connection with, the Subordinated Note, and all agreements,
devices or arrangements providing for payments which are relating to
fluctuations of interest rates, exchange rates or forward rates (including
without limitation any interest rate, swap agreements, dollar denominated or
cross currency interest rate exchange agreements, forward currency exchange
agreements, interest rate cap or collar protection agreements, forward rate
currency or interest rate options, puts and warrants) entered into by the
Company with any Subordinated Lender at any time, as all of the foregoing may be
amended, modified, supplemented, extended, renewed, restated or replaced from
time to time.

                     "Subordinated Note" means the Subordinated Revolving Loan
Promissory Note due in October, 2009 in the principal amount of $100,000,000
dated as of October 1, 1999 of the Company payable to the Subordinated Lender,
as amended, modified, supplemented, extended, renewed, restated, restructured,
refinanced or replaced from time to time, and including any agreement entered
into in substitution thereof.

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                     1.2 Other Terms. Capitalized terms not otherwise defined
herein shall have the meanings given to them in the Credit Agreement.

                     1.3 Certain Matters of Construction. The terms "herein",
"hereof" and "hereunder" and other words of similar import refer to this
Agreement as a whole and not to any particular section, paragraph or
subdivision. Any pronoun used shall be deemed to cover all genders. Wherever
appropriate in the context, terms used herein in the singular also include the
plural and vice versa. All references to statutes and related regulations shall
include any amendments of same and any successor statutes and regulations. All
references to any instruments or agreements, including, without limitation,
references to any of the Senior Lending Agreements or Subordinated Lending
Agreements shall include any and all modifications or amendments thereto and any
and all extensions or renewals thereof.

               2. Covenants. The Company and each Holder of Subordinated
Indebtedness hereby covenant that until the Senior Indebtedness shall have been
irrevocably paid in full and satisfied in cash and the Credit Agreement and any
letters of credit issued pursuant thereto shall have been irrevocably
terminated, all in accordance with the terms of the Credit Agreement and the
other Senior Lending Agreements, each agrees and will comply with such of the
following provisions as are applicable to it:

                     2.1 Transfers; Etc. Each Holder of Subordinated
Indebtedness covenants it will not assign or otherwise transfer any of the
Subordinated Indebtedness or any of the Subordinated Lending Agreements without
the prior written consent of the Agent. Each Holder of Subordinated Indebtedness
covenants that any transferee from it of any Subordinated Indebtedness or any
Liens (if any) securing any Subordinated Indebtedness shall, prior to acquiring
such interest, execute and deliver a counterpart of this Subordination Agreement
to each other party hereto. The Company covenants that any holder of any
Subordinated Indebtedness at any time and any Guarantor shall promptly execute
and deliver a counterpart of this Subordination Agreement to each other party
hereto.

                     2.2 Subordinated Indebtedness Subordination Provisions. To
induce Senior Lenders to enter into the Credit Agreement and to make and
continue to make from time to time loans and advances thereunder,
notwithstanding any other provision of the Subordinated Indebtedness or the
Subordinated Lending Agreements to the contrary, any Distribution with respect
to the Subordinated Indebtedness is and shall be expressly junior and
subordinated in right of payment to all amounts due and owing upon all Senior
Indebtedness from time to time. Specifically, but not by way of limitation:

                            (a) Payments. Neither the Company nor any other
Obligor shall make any Distribution on the Subordinated Indebtedness until such
time as the Senior Indebtedness shall have been irrevocably paid in full in cash
and the Credit Agreement and any letters of credit issued pursuant thereto shall
have been irrevocably terminated.

                            (b) Limitation on Acceleration. No Holder of
Subordinated Indebtedness shall be entitled to accelerate the maturity of the
Subordinated Indebtedness, exercise any remedies with respect to the
Subordinated Indebtedness, commence or join with any other creditors in
commencing any bankruptcy, reorganization, receivership or insolvency proceeding
against the Company or any Obligor or commence any other action or proceeding to
recover any amounts due or to become due with respect to Subordinated
Indebtedness until such time as the Senior Indebtedness shall have been
irrevocably paid in full in cash and the Credit Agreement and any letters of
credit issued pursuant thereto shall have been irrevocably terminated.

                            (c) Prior Payment of Senior Indebtedness in
Bankruptcy, Etc. In the event of any insolvency or bankruptcy proceedings
relative to the Company or any other Obligor or any of their respective
property, or any receivership, liquidation, reorganization or other similar
proceedings in connection therewith, or, in the event of any proceedings for
voluntary liquidation, dissolution or other winding up of the Company or any
other Obligor or distribution or marshaling of its assets or any composition
with creditors of the Company or any other Obligor, whether or not involving
insolvency or bankruptcy, or if the Company or any other Obligor shall cease its
operations, call a meeting of its creditors or no longer do business as a going
concern (each individually or collectively, an "Insolvency Event") then all
Senior Indebtedness shall be paid in full in cash and the Credit Agreement
irrevocably terminated before any Distribution shall be made on account of any
Subordinated Indebtedness, provided, however, that Holders of Subordinated
Indebtedness may receive (and shall be entitled to retain) securities which are
subordinate to (at least to the extent that the Subordinated Indebtedness is
subordinate to the Senior Indebtedness pursuant to the terms hereof) the payment
of all Senior Indebtedness. Any such Distribution which would, but for the
provisions hereof, be payable or deliverable in respect of the Subordinated
Indebtedness, shall be paid or delivered directly to the Senior Lenders or their
representatives, in the proportions in which they hold the same, until all
amounts owing upon the Senior Indebtedness shall have been irrevocably paid in
full in cash and the Credit Agreement and any letters of credit issued pursuant
thereto have been irrevocably terminated.

                            (d) Power of Attorney. To enable the Senior Lenders
to assert and enforce its rights hereunder in any proceeding referred to in
Section 2.2(c) or upon the happening of any Insolvency Event, the Agent or any
other Person whom the Senior Lenders may designate is hereby irrevocably

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appointed attorney in fact for such Holder of Subordinated Indebtedness with
full power to act in the place and stead of such Holder of Subordinated
Indebtedness including the right to make, present, file and vote such proofs of
claim against the Company or any other Obligor on account of all or any part of
the Subordinated Indebtedness as Agent may deem advisable and to receive and
collect any and all dividends or other payments made thereon and to apply the
same on account of the Senior Indebtedness but excluding the right to exercise
voting or approvals rights. The Subordinated Lenders will execute and deliver to
the Senior Lenders such instruments as may be required by the Senior Lenders to
enforce any and all Subordinated Indebtedness, to effectuate the aforesaid power
of attorney and to effect collection of any and all dividends or other payments
which may be made at any time on account thereof.

                            (e) Payments Held In Trust. Should any Distribution
or the proceeds thereof, in respect of the Subordinated Indebtedness, be
collected or received by any Holder of Subordinated Indebtedness or any
Affiliate of any such holder at a time when the Holders of Subordinated
Indebtedness are not permitted, pursuant to the terms hereof, to receive any
such Distribution or proceeds thereof, then each Holder of Subordinated
Indebtedness will forthwith deliver, or cause to be delivered, the same to the
Senior Lenders in precisely the form held by such Holder of Subordinated
Indebtedness (plus any necessary endorsements) and, until so delivered, the same
shall be held in trust by each Holder of Subordinated Indebtedness, or any such
Affiliate, as the property of the Senior Lenders and shall not be commingled
with other property of such Holder of Subordinated Indebtedness or any such
Affiliate.

                            (f) Subrogation. Subject to the prior payment in
full in cash of the Senior Indebtedness and the irrevocable termination of the
Credit Agreement and all Letters of Credit issued pursuant thereto, to the
extent that Senior Lenders have received any Distribution on the Senior
Indebtedness which, but for this Agreement, would have been applied to the
Subordinated Indebtedness, the Subordinated Lenders shall be subrogated to the
then or thereafter rights of the Senior Lenders including, without limitation,
the right to receive any Distribution made on the Senior Indebtedness until the
principal of, interest on and other charges due under the Subordinated
Indebtedness shall be paid in full; and, for the purposes of such subrogation,
no Distribution to the Senior Lenders to which the Subordinated Lenders would be
entitled except for the provisions of this Agreement, and no delivery to the
Senior Lenders by the Subordinated Lenders pursuant to Section 2.2(g) hereof,
shall, as between the Company, its creditors (other than the Senior Lenders) and
the Subordinated Lender, be deemed to be a Distribution by the Company to or on
account of Senior Indebtedness, it being understood that the provisions hereof
are and are intended solely for the purpose of defining the relative rights of
the Subordinated Lenders on the one hand, and the Senior Lenders on the other
hand.

                      2.3    Liens.  The Company, the other Obligors and the
Subordinated Lenders acknowledge, agree and represent and warrant to the Senior
Lenders that there are not and will not be any Liens on or with respect to any
assets of the Company, any Guarantor or any other Obligor at any time to secure
all or any part of the Subordinated Indebtedness and any such Lien shall be null
and void.

               3.     Miscellaneous.

                      3.1    Scope of Subordination; Reliance.  The provisions
of this Agreement are solely to define the relative rights of the Holders of
Subordinated Indebtedness and the Senior Lenders. Nothing in this Agreement
shall impair, as between the Company and the Holders of Subordinated
Indebtedness, the unconditional and absolute obligation of the Company to
punctually pay the principal, interest and any other amounts and obligations
owing under the Subordinated Lending Agreements in accordance with the terms
thereof, subject to the rights of the Senior Lenders under this Agreement. The
Subordinated Lenders acknowledge and agree that this Agreement is, and is
intended to be, an inducement and a consideration to the Senior Lenders for
entering into the Senior Lending Agreements and lending and continuing to hold
any Senior Indebtedness, whether such Senior Indebtedness was created or
acquired before or after the issuance of the Subordinated Indebtedness, to
acquire and continue to hold such Senior Indebtedness, and the Senior Lending
Agreements were initially entered into in reliance on the Subordinated Lender's
agreement to execute this Agreement. The Senior Lenders shall be deemed
conclusively to have relied on such subordination provisions in acquiring and
continuing to hold the Senior Indebtedness.

                      3.2    Provisions of Subordinated Lending Agreements.
From and after the date hereof, the Company, each other Obligor and the
Subordinated Lenders shall cause each Subordinated Lending Agreement to contain
a provision to the following effect:

               "This [describe agreement/instrument] is subject to the
               Subordination Agreement, dated as of December 31, 1999, among the
               Company, the Holders of Subordinated Indebtedness (as defined
               therein) and Bank One, Michigan, as agent for the Senior Lenders,
               under which this [describe agreement/instrument] and the
               [Obligor's] obligations hereunder and other rights of the Holder
               are subordinated in the manner set forth therein to the prior
               payment of obligations to the holders of Senior Indebtedness as
               defined therein and all collateral security therefor."

Proof of compliance with the foregoing shall be promptly given to Senior
Lenders.

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                      3.3 Survival of Rights. The right of Senior Lenders to
enforce the provisions of this Agreement shall not be prejudiced or impaired by
any act or omitted act of any Senior Lender, the Company, any Guarantor or any
other Person, including forbearance, waiver, consent, compromise, amendment,
extension, renewal, or taking or release of security in respect of any Senior
Indebtedness or noncompliance by the Company, any Guarantor or any other Person
with such provisions, regardless of the actual or imputed knowledge of Senior
Lenders. In the event that the Senior Indebtedness is refinanced in full, each
Holder of Subordinated Indebtedness agrees at the request of such refinancing
party to enter into a subordination agreement on terms substantially the same as
this Subordination Agreement.

                      3.4 Amendments to Senior Lending Agreements. Nothing
contained in this Agreement, or in any other agreement or instrument binding
upon any of the parties hereto, shall in any manner limit or restrict the
ability of the Senior Lenders from increasing or changing the terms of the
Obligations under the Senior Lending Agreements, or to otherwise waive, amend or
modify the terms and conditions of the Senior Lending Agreements, in such manner
as the Senior Lenders and the Company shall mutually determine. Each Holder of
Subordinated Indebtedness hereby consents to any and all such waivers,
amendments, modifications and compromises, and any other renewals, extensions,
indulgences, releases of collateral or other accommodations granted by the
Senior Lenders to the Company or any other Obligor from time to time, and agrees
that none of such actions shall in any manner affect or impair the subordination
established by this Subordination Agreement in respect of the Subordinated
Indebtedness. Without limiting the foregoing, and without notice to or the
consent of the Subordinated Lender, the Senior Lenders may, at any time and from
time to time and without impairing or releasing the subordination herein made,
do any one or more of the following: (a) change the manner, place or terms of
payment, or change or extend the time of payment of the Senior Indebtedness, or
amend or supplement in any manner the documentation evidencing, securing or
relating to the Senior Indebtedness, or increase without limit the amount of the
Senior Indebtedness; (b) release any person liable in any manner for the payment
or collection of the Senior Indebtedness; (c) exercise or refrain from
exercising any rights with respect to the Senior Indebtedness against the
Company or any of its Subsidiaries, any Guarantor or any other person; (d) apply
any monies or other property paid by any person or otherwise available to the
Senior Indebtedness; (e) accept or release, or fail to perfect an interest in,
any collateral or security for the Senior Indebtedness; or (f) take or omit to
take any other action with respect to the Senior Indebtedness which may impair
or adversely affect the subordination herein made.

                      3.5 Notices. Any notice or other communication required or
permitted pursuant to this Agreement shall be deemed given (a) when personally
delivered to any officer of the party to whom it is addressed, (b) on the
earlier of actual receipt thereof or three (3) days following posting thereof by
certified or registered mail, postage prepaid, (c) upon actual receipt thereof
when sent by a recognized overnight delivery service or (d) upon actual receipt
thereof when sent by telecopier to the number set forth below with electronic
confirmation of receipt, in each case addressed to each party at its address set
forth below or at such other address as has been furnished in writing by a party
to the other by like notice:

         If to Senior Lenders:              c/o Bank One
                                            100 East Broad Street
                                            7th Floor
                                            Columbus, OH  43215
                                            Attn: Thomas E. Redmond
                                            Phone: 614-248-5540
                                            Fax: 614-248-5518

         If to the Subordinated Lenders:    AirNet Management, Inc.
                                            4700 E. Fifth Avenue
                                            Columbus, Ohio  43219
                                            Attention:  Julie Hughes, Controller
                                            Telephone:  614-236-3840
                                            Telecopier:  614-2381969

         If to Company:                     AirNet Systems, Inc.
                                            3939 International Gateway
                                            Columbus, Ohio  43219
                                            Attention:  William R. Sumser
                                            Telephone:  614-236-3850
                                            Telecopier:  614-237-7876

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                      3.6 Representations. The Subordinated Lender and the
Company each hereby represent and warrant that: (a) attached hereto as Exhibit A
is a true, correct and complete copy of the Subordinated Note, the sole original
of the Subordinated Note has been conspicuously imprinted with the legend
required by Section 3.2 hereof, and there are no other documents, agreements or
instruments evidencing, securing or relating in any way to the Subordinated
Indebtedness; (b) all Subordinated Lending Agreements are attached hereto as
Exhibit B, and there are no other documents, agreements or instruments
evidencing, securing or relating in any way to the Subordinated Indebtedness
other than those attached hereto as Exhibits A and B; (c) the Subordinated
Lender has not relied and will not rely on any representation or information of
any nature made by or received from the Senior Lenders in deciding to execute
this Agreement; (d) the Subordinated Lender has not heretofore assigned or
transferred any of the Subordinated Indebtedness, any interest therein or any
other rights pertaining thereto; (e) the Subordinated Lender has not heretofore
given any subordination in respect of the Subordinated Indebtedness; (f) the
execution, delivery and performance of this Agreement are within its corporate
powers, have been duly authorized and are not in contravention of law or, if
applicable, of the terms of its articles of incorporation or bylaws, or of any
law, order, judgment, decree, contract or undertaking to which it is a party or
by which it or any of its properties is bound or affected; and (g) this
Agreement constitutes the legal, valid and binding obligation of each of them,
enforceable against each in accordance with its terms.

                      3.7 Additional Covenants. Until all of the Senior
Indebtedness has been irrevocably paid in full in cash and the Credit Agreement
and any letters of credit issued pursuant thereto have expired or been
terminated, unless otherwise consented to by the Agent in writing: (a) the
Company and the Subordinated Lenders shall not assign, transfer, hypothecate or
modify, terminate, amend or supplement, or consent to any cancellation,
modification, termination, amendment or supplement of, any Subordinated Lending
Agreement or any of the other terms of the Subordinated Indebtedness; (b) the
Subordinated Lenders shall not hereafter give any subordination in respect to
the Subordinated Indebtedness; (c) the Company and the Subordinated Lenders will
not hereafter issue any instrument, agreement or other writing evidencing or
securing any part of the Subordinated Indebtedness or allow any liens or
securing interests on or with respect to any of its assets to secure any part of
the Subordinated Indebtedness, and the Subordinated Lenders will not receive any
such instrument, security or other writing of any such liens or securing
interests, and any such instrument, security or other writing and any such liens
or security interests shall be null and void; and (d) the Company and the
Subordinated Lenders shall give the Senior Lender prompt notice of any default
under the Subordinated Indebtedness.

                      3.8 Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Michigan, without giving
effect to the choice of law principles of such State.

                      3.9 Counterparts. This Agreement may be executed in any
number of counterparts, all of which taken together shall constitute one in the
same instrument and any of the parties hereto may execute this Agreement by
signing any such counterpart.

                      3.10 Amendments; Successors and Assigns. No provision of
this Agreement may be modified or waived except by an instrument or instruments
in writing signed by the Senior Lenders (or the requisite number of Senior
Lenders as may be required pursuant to the Senior Lending Agreements), the
Subordinated Lenders (or the requisite number of Subordinated Lenders as may be
required under the Subordinated Lending Agreements) and the Company. This
Agreement shall bind the parties hereto and their respective successors and
assigns, and shall inure to the benefit of their respective successors and
assigns.

                      3.11 This Agreement Controls. The subordination and
related provisions contained in this Agreement are in addition to and supplement
all debt subordination and other provisions contained in the Subordinated
Lending Agreements and any other instruments or agreements evidencing or
relating to the Subordinated Indebtedness in favor of or for the benefit of the
Senior Lenders; provided that, in the event of any conflict between this
Agreement and the Subordinated Lending Agreements or such other instruments and
agreements, the terms of this Agreement shall control.

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        WITNESS the due execution of this Agreement as of the day and year first
above written.

                               BANK ONE, MICHIGAN,
                               as Agent for the Senior Lenders

                               By: ____________________________________
                                  Title:_______________________________

                               AIRNET SYSTEMS, INC.

                               By: ____________________________________
                                  Title:_______________________________

                               AIRNET MANAGEMENT, INC.

                               By: ____________________________________
                                  Title:_______________________________

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                                    EXHIBIT A

                            Copy of Subordinated Note

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                                    EXHIBIT B

                   Copy of all Subordinated Lending Agreements

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                                                                     EXHIBIT 4.5

                               SUBSIDIARY GUARANTY

        THIS SUBSIDIARY GUARANTY (this "Guaranty") is made as of the 31st day of
December, 1999, by AirNet Management, Inc., an Ohio corporation (the "Subsidiary
Guarantor") in favor of the Agent, for the benefit of the Lenders, under the
Credit Agreement referred to below;

                                   WITNESSETH:

        WHEREAS, AirNet Systems, Inc., an Ohio corporation (the "Principal"),
certain Lenders from time to time party thereto and Bank One, Michigan, formerly
known as NBD Bank, as agent for the Lenders (in such capacity, together with any
successor agent, the "Agent") have entered into a certain Credit Agreement dated
as of August 1, 1998, as amended by that certain First Amendment to Credit
Agreement dated as of September 30, 1998, and as further amended by that certain
Second Amendment to Credit Agreement dated of even date herewith (as same may be
amended or modified from time to time, the "Credit Agreement"), providing,
subject to the terms and conditions thereof, for extensions of credit to be made
by the Lenders to the Principal;

        WHEREAS, it is pursuant to Section 5.1(f) of the Credit Agreement that
the Subsidiary Guarantor executes and delivers this Guaranty whereby the
Subsidiary Guarantor shall guarantee the payment when due, subject to Section 9
hereof, of all Guaranteed Obligations, as defined below; and

        WHEREAS, in consideration of the financial and other support that the
Principal has provided, and such financial and other support as the Principal
may in the future provide to the Subsidiary Guarantor, and in order to induce
the Lenders and the Agent to enter into the Credit Agreement, and the Lenders
and their Affiliates to enter into one or more Rate Management Transactions with
the Principal, and because the Subsidiary Guarantor has determined that
executing this Guaranty is in its interest and to its financial benefit, the
Subsidiary Guarantor is willing to guarantee the obligations of the Principal
under the Credit Agreement, any Note, any Rate Management Transaction, and the
other Loan Documents;

        NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

        SECTION  l.1.  Selected Terms Used Herein.

        "Guaranteed Obligations" is defined in Section 3 below.

        "Rate Management Transaction" means any transaction (including an
agreement with respect thereto) now existing or hereafter entered into between
the Principal and any Lender or Affiliate thereof which is a rate swap, basis
swap, forward rate transaction, commodity swap, commodity option, equity or
equity index swap, equity or equity index option, bond option, interest rate
option, foreign exchange transaction, cap transaction, floor transaction, collar
transaction, forward transaction, currency swap transaction, cross-currency rate
swap transaction, currency option or any other similar transaction (including
any option with respect to any of these transactions) or any combination
thereof, whether linked to one or more interest rates, foreign currencies,
commodity prices, equity prices or other financial measures.

        "Rate Management Obligations" means any and all obligations of the
Principal, whether absolute or contingent and howsoever and whensoever created,
arising, evidenced or acquired (including all renewals, extensions and
modifications thereof and substitutions therefor), under (i) any and all Rate
Management Transactions, and (ii) any and all cancellations, buy backs,
reversals, terminations or assignments of any Rate Management Transactions.

        SECTION 1.2. Terms in Credit Agreement. Other capitalized terms used
herein but not defined herein shall have the meaning set forth in the Credit
Agreement.

        SECTION 2.1. Representations and Warranties. The Subsidiary Guarantor
represents and warrants (which representations and warranties shall be deemed to
have been renewed upon each date an Advance is made under the Credit Agreement)
that:

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<PAGE>

               (a) It is a corporation, partnership or limited liability company
duly and properly incorporated or organized, as the case may be, validly
existing and (to the extent such concept applies to such entity) in good
standing under the laws of its jurisdiction of incorporation or organization and
has all requisite authority to conduct its business in each jurisdiction in
which its business is conducted.

               (b) It has the power and authority and legal right to execute and
deliver this Guaranty and to perform its obligations hereunder. The execution
and delivery by it of this Guaranty and the performance of its obligations
hereunder have been duly authorized by proper corporate proceedings, and this
Guaranty constitutes a legal, valid and binding obligation of such Subsidiary
Guarantor enforceable against it in accordance with its terms, except as
enforceability may be limited by bankruptcy, insolvency or similar laws
affecting the enforcement of creditors' rights generally.

               (c) Neither the execution and delivery by it of this Guaranty,
nor the consummation of the transactions herein contemplated, nor compliance
with the provisions hereof will violate (i) any law, rule, regulation, order,
writ, judgment, injunction, decree or award binding on it or any of its
subsidiaries or (ii) its articles or certificate of incorporation, partnership
agreement, certificate of partnership, articles or certificate of organization,
by-laws, or operating or other management agreement, as the case may be, or
(iii) the provisions of any indenture, instrument or agreement to which it or
any of its subsidiaries is a party or is subject, or by which it, or its
property, is bound, or conflict with or constitute a default thereunder, or
result in, or require, the creation or imposition of any Lien in, of or on the
property of such Subsidiary Guarantor or a subsidiary thereof pursuant to the
terms of any such indenture, instrument or agreement. No order, consent,
adjudication, approval, license, authorization, or validation of, or filing,
recording or registration with, or exemption by, or other action in respect of
any governmental or public body or authority, or any subdivision thereof, which
has not been obtained by it or any of its subsidiaries, is required to be
obtained by it or any of its subsidiaries in connection with the execution and
delivery of this Guaranty or the performance by it of its obligations hereunder
or the legality, validity, binding effect or enforceability of this Guaranty.

        SECTION 2.2. Covenants. The Subsidiary Guarantor covenants that, so long
as any Lender has any Commitment outstanding under the Credit Agreement, any
Rate Management Transaction remains in effect or any of the Guaranteed
Obligations shall remain unpaid, that it will, and, if necessary, will enable
the Principal to, fully comply with those covenants and agreements set forth in
the Credit Agreement.

        SECTION 3. The Guaranty. Subject to Section 9 hereof, the Subsidiary
Guarantor hereby absolutely and unconditionally guarantees, as primary obligor
and not as surety, the full and punctual payment (whether at stated maturity,
upon acceleration or early termination or otherwise, and at all times
thereafter) and performance of the Obligations and the Rate Management
Obligations, including without limitation any such Obligations or Rate
Management Obligations incurred or accrued during the pendency of any
bankruptcy, insolvency, receivership or other similar proceeding, whether or not
allowed or allowable in such proceeding (collectively, subject to the provisions
of Section 9 hereof, being referred to as the "Guaranteed Obligations"). Upon
failure by the Principal to pay punctually any such amount, the Subsidiary
Guarantor agrees that it shall forthwith on demand pay to the Agent for the
benefit of the Lenders and, if applicable, their Affiliates, the amount not so
paid at the place and in the manner specified in the Credit Agreement, any Note,
any Rate Management Transaction or the relevant Loan Document, as the case may
be. This Guaranty is a guaranty of payment and not of collection. The Subsidiary
Guarantor waives any right to require the Lender to sue the Principal, any other
guarantor, or any other person obligated for all or any part of the Guaranteed
Obligations, or otherwise to enforce its payment against any collateral securing
all or any part of the Guaranteed Obligations.

        SECTION 4. Guaranty Unconditional. Subject to Section 9 hereof, the
obligations of the Subsidiary Guarantor hereunder shall be unconditional and
absolute and, without limiting the generality of the foregoing, shall not be
released, discharged or otherwise affected by:

        (i) any extension, renewal, settlement, compromise, waiver or release in
        respect of any of the Guaranteed Obligations, by operation of law or
        otherwise, or any obligation of any other guarantor of any of the
        Guaranteed Obligations, or any default, failure or delay, willful or
        otherwise, in the payment or performance of the Guaranteed Obligations;

        (ii) any modification or amendment of or supplement to the Credit
        Agreement, any Note, any Rate Management Transaction or any other Loan
        Document;

        (iii) any release, nonperfection or invalidity of any direct or indirect
        security for any obligation of the Principal under the Credit Agreement,
        any Note, any Rate Management Transaction, any other Loan Document, or
        any obligations of any other guarantor of any of the Guaranteed
        Obligations, or any action or failure to act by the Agent, any Lender or
        any Affiliate of any Lender with respect to any collateral securing all
        or any part of the Guaranteed Obligations;

                                       11
<PAGE>

        (iv) any change in the corporate existence, structure or ownership of
        the Principal or any other guarantor of any of the Guaranteed
        Obligations, or any insolvency, bankruptcy, reorganization or other
        similar proceeding affecting the Principal, or any other guarantor of
        the Guaranteed Obligations, or its assets or any resulting release or
        discharge of any obligation of the Principal, or any other guarantor of
        any of the Guaranteed Obligations;

        (v) the existence of any claim, setoff or other rights which the
        Subsidiary Guarantor may have at any time against the Principal, any
        other guarantor of any of the Guaranteed Obligations, the Agent, any
        Lender or any other Person, whether in connection herewith or any
        unrelated transactions;

        (vi) any invalidity or unenforceability relating to or against the
        Principal, or any other guarantor of any of the Guaranteed Obligations,
        for any reason related to the Credit Agreement, any Rate Management
        Transaction, any other Loan Document, or any provision of applicable law
        or regulation purporting to prohibit the payment by the Principal, or
        any other guarantor of the Guaranteed Obligations, of the principal of
        or interest on any Note or any other amount payable by the Principal
        under the Credit Agreement, any Note, any Rate Management Transaction or
        any other Loan Document; or

        (vii) any other act or omission to act or delay of any kind by the
        Principal, any other guarantor of the Guaranteed Obligations, the Agent,
        any Lender or any other Person or any other circumstance whatsoever
        which might, but for the provisions of this paragraph, constitute a
        legal or equitable discharge of the Subsidiary Guarantor's obligations
        hereunder.

        SECTION 5. Discharge Only Upon Payment In Full: Reinstatement In Certain
Circumstances. The Subsidiary Guarantor's obligations hereunder shall remain in
full force and effect until all Guaranteed Obligations shall have been
indefeasibly paid in full, the Commitments under the Credit Agreement shall have
terminated or expired and all Rate Management Transactions have terminated or
expired. If at any time any payment of the principal of or interest on any Note
or any other amount payable by the Principal or any other party under the Credit
Agreement, any Rate Management Transaction or any other Loan Document is
rescinded or must be otherwise restored or returned upon the insolvency,
bankruptcy or reorganization of the Principal or otherwise, each of the
Subsidiary Guarantor's obligations hereunder with respect to such payment shall
be reinstated as though such payment had been due but not made at such time.

        SECTION 6. Waivers. The Subsidiary Guarantor irrevocably waives
acceptance hereof, presentment, demand, protest and, to the fullest extent
permitted by law, any notice not provided for herein, as well as any requirement
that at any time any action be taken by any Person against the Principal, any
other guarantor of any of the Guaranteed Obligations, or any other Person.

        SECTION 7. Subrogation. The Subsidiary Guarantor hereby agrees not to
assert any right, claim or cause of action, including, without limitation, a
claim for subrogation, reimbursement, indemnification or otherwise, against the
Principal arising out of or by reason of this Guaranty or the obligations
hereunder, including, without limitation, the payment or securing or purchasing
of any of the Guaranteed Obligations by the Subsidiary Guarantor unless and
until the Guaranteed Obligations are indefeasibly paid in full, any commitment
to lend under the Credit Agreement and any other Loan Documents is terminated
and all Rate Management Transactions have terminated or expired.

        SECTION 8. Stay of Acceleration. If acceleration of the time for payment
of any of the Guaranteed Obligations is stayed upon the insolvency, bankruptcy
or reorganization of the Principal, all such amounts otherwise subject to
acceleration under the terms of the Credit Agreement, any Note, any Rate
Management Transaction or any other Loan Document shall nonetheless be payable
by the Subsidiary Guarantor hereunder forthwith on demand by the Agent made at
the request of the Required Lenders.

        SECTION 9. Limitation on Obligations. (a) The provisions of this
Guaranty are severable, and in any action or proceeding involving any state
corporate law, or any state, federal or foreign bankruptcy, insolvency,
reorganization or other law affecting the rights of creditors generally, if the
obligations of the Subsidiary Guarantor under this Guaranty would otherwise be
held or determined to be avoidable, invalid or unenforceable on account of the
amount of such Subsidiary Guarantor's liability under this Guaranty, then,
notwithstanding any other provision of this Guaranty to the contrary, the amount
of such liability shall, without any further action by the Subsidiary Guarantor,
the Agent or any Lender, be automatically limited and reduced to the highest
amount that is valid and enforceable as determined in such action or proceeding
(such highest amount determined hereunder being the Subsidiary Guarantor's
"Maximum Liability"). This Section 9(a) with respect to the Maximum Liability of
the Subsidiary Guarantor is intended solely to preserve the rights of the Agent
hereunder to the maximum extent not subject to avoidance under applicable law,
and neither the Subsidiary Guarantor nor any other person or entity shall have
any right or claim under this Section 9(a) with respect to the Maximum
Liability, except to the extent necessary so that the obligations of the
Subsidiary Guarantor hereunder shall not be rendered voidable under applicable
law.

        (b) The Subsidiary Guarantor agrees that the Guaranteed Obligations may
at any time and from time to time exceed the Maximum Liability of such
Subsidiary Guarantor, and may exceed the aggregate Maximum Liability of all
other Subsidiary Guarantors, without impairing this Guaranty or affecting the
rights and remedies of the Agent hereunder. Nothing in this Section 9(b) shall
be construed to increase the Subsidiary Guarantor's obligations hereunder beyond
its Maximum Liability.

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<PAGE>

        (c) In the event any Subsidiary Guarantor (a "Paying Subsidiary
Guarantor") shall make any payment or payments under this Guaranty or shall
suffer any loss as a result of any realization upon any collateral granted by it
to secure its obligations under this Guaranty, each other Subsidiary Guarantor
(each a "Non-Paying Subsidiary Guarantor") shall contribute to such Paying
Subsidiary Guarantor an amount equal to such Non-Paying Subsidiary Guarantor's
"Pro Rata Share" of such payment or payments made, or losses suffered, by such
Paying Subsidiary Guarantor. For the purposes hereof, each Non-Paying Subsidiary
Guarantor's "Pro Rata Share" with respect to any such payment or loss by a
Paying Subsidiary Guarantor shall be determined as of the date on which such
payment or loss was made by reference to the ratio of (i) such Non-Paying
Subsidiary Guarantor's Maximum Liability as of such date (without giving effect
to any right to receive, or obligation to make, any contribution hereunder) or,
if such Non-Paying Subsidiary Guarantor's Maximum Liability has not been
determined, the aggregate amount of all monies received by such Non-Paying
Subsidiary Guarantor from the Principal after the date hereof (whether by loan,
capital infusion or by other means) to (ii) the aggregate Maximum Liability of
all Subsidiary Guarantors hereunder (including such Paying Subsidiary Guarantor)
as of such date (without giving effect to any right to receive, or obligation to
make, any contribution hereunder), or to the extent that a Maximum Liability has
not been determined for any Subsidiary Guarantors, the aggregate amount of all
monies received by such Subsidiary Guarantors from the Principal after the date
hereof (whether by loan, capital infusion or by other means). Nothing in this
Section 9(c) shall affect any Subsidiary Guarantor's several liability for the
entire amount of the Guaranteed Obligations (up to such Subsidiary Guarantor's
Maximum Liability). Each of the Subsidiary Guarantors covenants and agrees that
its right to receive any contribution under this Guaranty from a Non-Paying
Subsidiary Guarantor shall be subordinate and junior in right of payment to all
the Guaranteed Obligations. The provisions of this Section 9(c) are for the
benefit of both the Agent and the Subsidiary Guarantors and may be enforced by
any one, or more, or all of them in accordance with the terms hereof.

        SECTION 10. Application of Payments. All payments received by the Agent
hereunder shall be applied by the Agent to payment of the Guaranteed Obligations
in the following order unless a court of competent jurisdiction shall otherwise
direct:

               (a) FIRST, to payment of all costs and expenses of the Agent
        incurred in connection with the collection and enforcement of the
        Guaranteed Obligations or of any security interest granted to the Agent
        in connection with any collateral securing the Guaranteed Obligations;

               (b) SECOND, to payment of that portion of the Guaranteed
        Obligations constituting accrued and unpaid interest and fees, pro rata
        among the Lenders and their Affiliates in accordance with the amount of
        such accrued and unpaid interest and fees owing to each of them;

               (c) THIRD, to payment of the principal of the Guaranteed
        Obligations and the net early termination payments and any other Rate
        Management Obligations then due and unpaid from the Borrower to any of
        the Lenders or their Affiliates, pro rata among the Lenders and their
        Affiliates in accordance with the amount of such principal and such net
        early termination payments and other Rate Management Obligations then
        due and unpaid owing to each of them; and

               (d) FOURTH, to payment of any Guaranteed Obligations (other than
        those listed above) pro rata among those parties to whom such Guaranteed
        Obligations are due in accordance with the amounts owing to each of
        them.

        SECTION 11. Notices. All notices, requests and other communications to
any party hereunder shall be given or made by telecopier or other writing and
telecopied, or mailed or delivered to the intended recipient at its address or
telecopier number set forth on the signature pages hereof or such other address
or telecopy number as such party may hereafter specify for such purpose by
notice to the Agent in accordance with the provisions of Article XIII of the
Credit Agreement. Except as otherwise provided in this Guaranty, all such
communications shall be deemed to have been duly given when transmitted by
telecopier, or personally delivered or, in the case of a mailed notice sent by
certified mail return-receipt requested, on the date set forth on the receipt
(provided, that any refusal to accept any such notice shall be deemed to be
notice thereof as of the time of any such refusal), in each case given or
addressed as aforesaid.

        SECTION 12. No Waivers. No failure or delay by the Agent or any Lenders
in exercising any right, power or privilege hereunder shall operate as a waiver
thereof nor shall any single or partial exercise thereof preclude any other or
further exercise thereof or the exercise of any other right, power or privilege.
The rights and remedies provided in this Guaranty, the Credit Agreement, any
Note, any Rate Management Transaction and the other Loan Documents shall be
cumulative and not exclusive of any rights or remedies provided by law.

        SECTION 13. No Duty to Advise. The Subsidiary Guarantor assumes all
responsibility for being and keeping itself informed of the Principal's
financial condition and assets, and of all other circumstances bearing upon the
risk of nonpayment of the Guaranteed Obligations and the nature, scope and
extent of the risks that the Subsidiary Guarantor assumes and incurs under this

                                       13
<PAGE>

Guaranty, and agrees that neither the Agent nor any Lender has any duty to
advise the Subsidiary Guarantor of information known to it regarding those
circumstances or risks.

        SECTION 14. Successors and Assigns. This Guaranty is for the benefit of
the Agent and the Lenders and their respective successors and permitted assigns
and in the event of an assignment of any amounts payable under the Credit
Agreement, any Note, any Rate Management Transaction, or the other Loan
Documents, the rights hereunder, to the extent applicable to the indebtedness so
assigned, shall be transferred with such indebtedness. This Guaranty shall be
binding upon the Subsidiary Guarantor and its respective successors and
permitted assigns.

        SECTION 15. Changes in Writing. Neither this Guaranty nor any provision
hereof may be changed, waived, discharged or terminated orally, but only in
writing signed by the Subsidiary Guarantor and the Agent with the consent of the
Required Lenders.

        SECTION 16. Costs of Enforcement. The Subsidiary Guarantor agrees to pay
all costs and expenses including, without limitation, all court costs and
attorneys' fees and expenses paid or incurred by the Agent or any Lender or any
Affiliate of any Lender in endeavoring to collect all or any part of the
Guaranteed Obligations from, or in prosecuting any action against, the
Principal, the Subsidiary Guarantor or any other guarantor of all or any part of
the Guaranteed Obligations.

        SECTION 17. GOVERNING LAW; SUBMISSION TO JURISDICTION; WAIVER OF JURY
TRIAL. THIS GUARANTY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAW OF THE STATE OF MICHIGAN. THE SUBSIDIARY GUARANTOR HEREBY SUBMITS TO THE
NONEXCLUSIVE JURISDICTION OF THE UNITED STATES DISTRICT COURT FOR THE EASTERN
DISTRICT OF MICHIGAN AND OF ANY MICHIGAN STATE COURT SITTING IN DETROIT,
MICHIGAN AND FOR PURPOSES OF ALL LEGAL PROCEEDINGS ARISING OUT OF OR RELATING TO
THIS GUARANTY (INCLUDING, WITHOUT LIMITATION, ANY OF THE OTHER LOAN DOCUMENTS)
OR THE TRANSACTIONS CONTEMPLATED HEREBY. THE SUBSIDIARY GUARANTOR IRREVOCABLY
WAIVES, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW
OR HEREAFTER HAVE TO THE LAYING OF THE VENUE OF ANY SUCH PROCEEDING BROUGHT IN
SUCH A COURT AND ANY CLAIM THAT ANY SUCH PROCEEDING BROUGHT IN SUCH A COURT HAS
BEEN BROUGHT IN AN INCONVENIENT FORUM. THE SUBSIDIARY GUARANTOR, AND THE AGENT
AND THE LENDERS ACCEPTING THIS GUARANTY, HEREBY IRREVOCABLY WAIVE ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO
THIS GUARANTY OR THE TRANSACTIONS CONTEMPLATED HEREBY.

        SECTION 18. Taxes. etc. All payments required to be made by the
Subsidiary Guarantor hereunder shall be made without setoff or counterclaim and
free and clear of and without deduction or withholding for or on account of, any
present or future taxes, levies, imposts, duties or other charges of whatsoever
nature imposed by any government or any political or taxing authority thereof
(but excluding excluded taxes), provided, however, that if the Subsidiary
Guarantor is required by law to make such deduction or withholding, such
Subsidiary Guarantor shall forthwith (i) pay to the Agent or any Lender, as
applicable, such additional amount as results in the net amount received by the
Agent or any Lender, as applicable, equaling the full amount which would have
been received by the Agent or any Lender, as applicable, had no such deduction
or withholding been made, (ii) pay the full amount deducted to the relevant
authority in accordance with applicable law, and (iii) furnish to the Agent or
any Lender, as applicable, certified copies of official receipts evidencing
payment of such withholding taxes within 30 days after such payment is made.

        IN WITNESS WHEREOF, the Subsidiary Guarantor has caused this Guaranty to
be duly executed, under seal, by its authorized officer as of the day and year
first above written.

                                           AIRNET MANAGEMENT, INC.

                                           By: __________________________

                                           Title: _______________________

                                           Address for Subsidiary Guarantor:
                                           AirNet Management, Inc.
                                           4700 E. Fifth Avenue
                                           Columbus, Ohio  43219

                                           Telecopy No.: (614) 238-1969

                                       14

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