Document:

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                                                                    EXHIBIT 10.2

                           WAIVER AND AMENDMENT NO. 4 dated as of May 10, 2001,
                  to the Credit Agreement dated as of August 12, 1999, as
                  amended (the "Credit Agreement"), among WFS HOLDINGS, INC., a
                  Delaware corporation ("Holdings"), WORLDWIDE FLIGHT SERVICES,
                  INC., a Delaware corporation (the "Borrower"), the lenders
                  party thereto (the "Lenders"), THE CHASE MANHATTAN BANK, a New
                  York banking corporation, as Administrative Agent, and DLJ
                  CAPITAL FUNDING, INC., as Syndication Agent.

         The Borrower has requested that the Lenders grant a limited waiver of
compliance with, and amend certain provisions of, the Credit Agreement in the
manner provided for in this Waiver and Amendment, and the undersigned Lenders
are willing to agree to such waiver and amendment, each as provided for in this
Waiver and Amendment.

         Accordingly, on the terms and subject to the conditions set forth
herein, the parties hereto hereby agree as follows:

         SECTION 1. Defined Terms. Capitalized terms used and not defined herein
shall have the meanings given to them in the Credit Agreement.

         SECTION 2. Waiver of Section 6.13 of the Credit Agreement (Leverage
Ratio). The Lenders hereby expressly waive any Default arising from the failure
to comply with, including any Default attributable to representations and
warranties made or affirmed by the Borrower upon any Credit Event regarding
compliance with, the requirement of Section 6.13 of the Credit Agreement that
the Leverage Ratio for the fiscal quarter ended March 31, 2001 not exceed 5.25
to 1.0.

         SECTION 3. Amendment to Section 6.13 of the Credit Agreement (Leverage
Ratio). Section 6.13 of the Credit Agreement is hereby amended by replacing the
table therein in its entirety with the following:

<TABLE>
<CAPTION>
                        Period                            Ratio
                        ------                            -----
<S>                                                    <C>

 September 30, 1999 through March 30, 2001             5.25 to 1.0
 March 31, 2001 through June 28, 2001                  6.0  to 1.0
 June 29, 2001 through September 29, 2001              5.25 to 1.0
 September 30, 2001 through September 29, 2002         5.0  to 1.0
 September 30, 2002 through September 29, 2003         4.75 to 1.0
 September 30, 2003 and thereafter                     4.5  to 1.0
</TABLE>

         SECTION 4. Representations and Warranties. Each of Holdings and the
Borrower represents and warrants to each of the Lenders that:

<PAGE>   2

                                                                               2

         (a) This Waiver and Amendment has been duly authorized, executed and
     delivered by each of Holdings and the Borrower.

         (b) After giving effect to this Waiver and Amendment, the
     representations and warranties of each of Holdings and the Borrower set
     forth in the Loan Documents are true and correct in all material respects
     on and as of the date hereof, in each case with the same effect as though
     made on and as of the date hereof, except to the extent such
     representations and warranties expressly relate to an earlier date.

         (c) On the date hereof and immediately after giving effect to this
     Waiver and Amendment, no Default has occurred and is continuing.

         SECTION 5. Conditions to Effectiveness. This Waiver and Amendment shall
become effective on the date (the "Amendment Effective Date") when (a) the
Administrative Agent shall have received counterparts of this Waiver and
Amendment that, when taken together, bear the signatures of Holdings, the
Borrower and the Required Lenders, (b) the Borrower shall have paid, to the
extent invoiced, all out-of-pocket expenses (including fees and charges of
counsel for the Administrative Agent) of the Administrative Agent required to be
paid or reimbursed by the Borrower under the Credit Agreement and (c) the
Administrative Agent shall have received payment of all fees payable by the
Borrower in connection with this Waiver and Amendment, including the fees
described in Section 9 below.

         SECTION 6. Credit Agreement. Except as specifically amended hereby, the
Credit Agreement shall continue in full force and effect in accordance with the
provisions thereof as in existence on the date hereof. After the date hereof,
any reference to the Credit Agreement shall mean the Credit Agreement as amended
hereby. This Waiver and Amendment shall be a Loan Document for all purposes.

         SECTION 7. APPLICABLE LAW. THIS WAIVER AND AMENDMENT SHALL BE GOVERNED
BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

         SECTION 8. Counterparts. This Waiver and Amendment may be executed in
two or more counterparts, each of which shall constitute an original but all of
which when taken together shall constitute but one agreement. Delivery of an
executed counterpart of a signature page of this Waiver and Amendment by
facsimile transmission shall be effective as delivery of a manually executed
counterpart of this Waiver and Amendment.

         SECTION 9. Amendment Fees. The Borrower agrees to pay to the
Administrative Agent, for the account of each Lender that delivers an executed
counterpart to this Waiver and Amendment prior to 5:00 p.m., New York City time,
on May 10, 2001 (or, if later, on the Amendment Effective Date), an amendment
fee equal to 0.125% of the sum of (a) the aggregate unpaid principal amount of
Term Loans held by such Lender as of 5:00 p.m., New York City time, on May 10,
2001, and (b) such Lender's Revolving Commitment in effect as of 5:00 p.m., New
York City time, on May 10, 2001; provided that the foregoing fee shall not be
payable unless this Waiver and Amendment becomes effective as provided in
Section 5 above.

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                                                                               3

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

                                  WFS HOLDINGS, INC.,

                                  By: /s/ D.F. Chavenson
                                      --------------------------------------
                                      Name:  D.F. Chavenson
                                      Title: Vice President

                                  WORLDWIDE FLIGHT SERVICES, INC.,

                                  By: /s/ D. F. Chavenson
                                      --------------------------------------
                                      Name:  D.F. Chavenson
                                      Title: Vice President

                                  THE CHASE MANHATTAN BANK,
                                  individually and as Administrative Agent,

                                  By: /s/ Matthew H. Massie
                                      --------------------------------------
                                      Name:  Matthew H. Massie
                                      Title: Managing Director

                                  THE BANK OF NOVA SCOTIA,

                                  By: /s/ F.C.H. Ashby
                                      --------------------------------------
                                      Name:  F.C.H. Ashby
                                      Title: Senior Manager
                                             Loan Operations

                                  THE CIT GROUP/EQUIPMENT
                                  FINANCING, INC.,

                                  By: /s/ Undrea L. Mitchell
                                      --------------------------------------
                                      Name:  Undrea L. Mitchell
                                      Title: Senior Credit Analyst

<PAGE>   4

                                                                               4

                                  CITIZENS BANK OF MASSACHUSETTS

                                  By: /s/ C. Andrew Piculell
                                      --------------------------------------
                                      Name:  C. Andrew Piculell
                                      Title: Vice President

                                  CREDIT SUISSE FIRST BOSTON,

                                  By: /s/ Joel Glodowski
                                      --------------------------------------
                                      Name:  Joel Glodowski
                                      Title: Managing Director

                                  UNION BANK OF CALIFORNIA,

                                  By: /s/ Marc Schaefer
                                      --------------------------------------
                                      Name:  Marc Schaefer
                                      Title: Vice President

                                  U.S. BANK NATIONAL ASSOCIATION,

                                  By: /s/ Robert J. York
                                      --------------------------------------
                                      Name:  Robert J. York
                                      Title: Senior Vice President<PAGE>   1
                                                                 EXHIBIT 10.01

                   INTERNATIONAL HUMANITARIAN DEVELOPMENT LTD.
                               "SERVING HUMANITY"
                     23/F KINWICK CENTRE, 32 HOLLYWOOD ROAD
                               CENTRAL, HONG KONG
          WEBSITE: HTTP://WWW.INTERNATIONALHUMANITARIANDEVELOPMENT.COM

                               PURCHASE AGREEMENT

This agreement between Beijing Longenge Culture Promotion Co., Ltd., located at
No. 1 Hong Wei Road, Shijing Shan District, Beijing, which operates the Beijing
Shenji Dansing School, hereinafter, referred to as the "Purhasor", and
International Humanitarian Development Ltd. a joint venture corporation
organized under the laws of Hong Kong, and located at 32 Hollywood Rd., Central
Hong Kong, hereinafter referred to as the "Seller" defines the terms of sale for
the reconstruction of the Beijing Shenji Dansing School.

Whereas the purchaser has created a plan for the construction and rehabilitation
of a new facility. These facilities will cover a 30000 sq. meter parcel of land
with 14400 square meters of buildings inclusive of:

         a central education building
         an experimental education building
         an apartment building
         a theatre
         an art gym
         a dining building
         a supporting building

The facilities budgets have been submitted by the purchasor.

The facilities design, and construction are the responsibility of the seller.

Both the buyer and the seller agree that the budget shall be an aggregate of
$25,000,000 USD (200,000,000 RMB), inclusive of interest costs. The seller will
submit final designs and budgets. Building sizes may vary in accordance with the
budgetary requirements.

This project requires a deposit of $5,000,000 USD.

Upon receipt of the deposit the seller shall begin the design and budgetary
process. This process shall take approximately 90 days. The completion of the
facilities is expected to take approximately 2 years.

The building standards for the theatre and school buildings is to be
International Building Code, while the dormitories and support facilities shall
be built in accordance with the Chinese construction standards and codes as
applicable.

The purchasors plans are an exhibit to this agreement. In addition to the
primary prices defined by the purchasor additional reserves for interest are
estimated at $1,000,000 USD, and a scholarship fund is to be set aside in the
amount of $1,750,000 USD.

This agreement may be terminated by either party for failure to perform in
accordance with the final approved budgets and plans. The effect of such
termination shall be return of the deposit less any documentable disbursements.

Disputes shall be settled by arbitration in Hong Kong. The international rules
of arbitration shall apply.

The seller warrants that the buildings shall be delivered in accordance with the
standards prescribed in this contract as well as the final budgetary proposal.

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The seller shall submit, file, present, all documentary requirements for these
buildings as prescribed by law.

The seller shall maintain proper public liability insurance during the
construction period.

The seller shall warrant the building be free of structural defects, and shall
effect repair to any structural defect for a period of one year.

The purchasor warrants that the specifications provided are adequate for the
proposed facilities.

The purchasor is responsible for all applicable academic, vocational, and
technical standards.

The purchasor is responsible for all licenses, permits, taxes, duties, transfer
fees, and regulatory approvals.

The governing law for this agreement shall be Hong Kong, SAR, Peoples Republic
of China.

We the owners, officers and directors of International Humanitarian Development
Ltd. set forth to this agreement our signatures and stamps with full corporate
authority and in agreement with the purchasor who sets forth his signature and
stamps with full corporate authority.

For and on behalf of: International Humanitarian Development Ltd.
Date: Feb 13, 2001

/s/  Lawrence Artz, Chairman, Neurotech Shareholder

/s/  Zhao Ly, Managing Director, CCS Shareholder

For and on behalf of: Bei Jing Longenge Culture Promotion Co. Ltd.
Date: Feb 13, 2001

/s/  Jing, Agent

Authorized by:
/s/  Jing Qi Zhu, director

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