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                                                                    EXHIBIT 3.24

                                     BY-LAWS

                                       OF

                             UNITED JET CENTER, INC.


                                    ARTICLE I

                                     OFFICES

      SECTION 1. REGISTERED OFFICE.--The registered office shall be established
and maintained at the office of The Prentice-Hall Corporation Services, Inc. in
the City of Dover, in the County of Kent, in the State of Delaware, and said
corporation shall be the registered agent of this corporation in charge thereof.

      SECTION 2. OTHER OFFICES.--The corporation may have other offices, either
within or without the State of Delaware, at such place or places as the Board of
Directors may from time to time appoint or the business of the corporation may
require.

                                   ARTICLE II

                            MEETINGS OF STOCKHOLDERS

      SECTION 1. ANNUAL MEETINGS.--Annual meetings of stockholders for the
election of directors and/or such other business as may be stated in the notice
of the meeting, shall be held at such place, either within or without the State
of Delaware, and at such time and date as the Board of Directors, by resolution,
shall determine and as set forth in the notice of the meeting. In the event the
Board of Directors fails to so determine the time, date and place of meeting,
the annual meeting of stockholders shall be held at the registered office of the
corporation in Delaware on May 15, 1989.

      If the date of the annual meeting shall fall upon a legal holiday, the
meeting shall be held on the next succeeding business day. At each annual
meeting, the stockholders entitled to vote shall elect a Board of Directors and
they may transact such other corporate business as shall be stated in the notice
of the meeting.

      SECTION 2. OTHER MEETINGS.--Meetings of stockholders for any purpose other
than the election of directors may be held at such time and place, within or
without the State of Delaware, as shall be stated in the notice of the meeting.
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      SECTION 3. VOTING.--Each Stockholder entitled to vote in accordance with
the terms of the Certificate of Incorporation and in accordance with the
provisions of these By-Laws shall be entitled to one vote, in person or by
proxy, for each share of stock entitled to vote held by such stockholder, but no
proxy shall be voted after three years from its date unless such proxy provides
for a longer period. Upon the demand of any stockholder, the vote for directors
and the vote upon any question before the meeting, shall be by ballot. All
elections for directors shall be decided by plurality vote; all other questions
shall be decided by majority vote except as otherwise provided by the
Certificate of Incorporation or the laws of the State of Delaware.

      A complete list of the stockholders entitled to vote at the ensuing
election, arranged in alphabetical order, with the address of each, and the
number of shares held by each, shall be open to the examination of any
stockholder, for any purpose germane to the meeting, during ordinary business
hours for a period of at least ten days prior to the meeting, either at a place
within the city where the meeting is to be held, which place shall be specified
in the notice of the meeting, or, if not so specified, at the place where the
meeting is to be held. The list shall also be produced and kept at the time and
place of the meeting during the whole time thereof, and may be inspected by any
stockholder who is present.

      SECTION 4. QUORUM.--Except as otherwise required by law, by the
Certificate of Incorporation or by these By-Laws, the presence, in person or by
proxy, of stockholders holding a majority of the stock of the corporation
entitled to vote shall constitute a quorum at all meetings of the stockholders.
In case a quorum shall not be present at any meeting, a majority in interest of
the stockholders entitled to vote thereat, present in person or by proxy, shall
have power to adjourn the meeting from time to time, without notice other than
announcement at the meeting, until the requisite amount of stock entitled to
vote shall be present. At any such adjourned meeting at which the requisite
amount of stock entitled to vote shall be represented, any business may be
transacted which might have been transacted at the meeting as originally
noticed; but only those stockholders entitled to vote at the meeting as
originally noticed shall be entitled to vote at any adjournment or adjournments
thereof.

      SECTION 5. SPECIAL MEETINGS.--Special meetings of the stockholders for any
purpose or purposes may be called by the President or Secretary, or by
resolution of the directors.


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      SECTION 6. NOTICE OF MEETINGS.--Written notice, stating the place, date
and time of the meeting, and the general nature of the business to be
considered, shall be given to each stockholder entitled to vote thereat at his
address as it appears on the records of the corporation, not less than ten nor
more than sixty days before the date of the meeting. No business other than that
stated in the notice shall be transacted at any meeting without the unanimous
consent of all the stockholders entitled to vote thereat.

      SECTION 7. ACTION WITHOUT MEETING.--Unless otherwise provided by the
Certificate of Incorporation, any action required to be taken at any annual or
special meeting of stockholders, or any action which may be taken at any annual
or special meeting, may be taken without a meeting, without prior notice and
without a vote, if a consent in writing, setting forth the action so taken,
shall be signed by the holders of outstanding stock having not less than the
minimum number of votes that would be necessary to authorize or take such action
at a meeting at which all shares entitled to vote thereon were present and
voted. Prompt notice of the taking of the corporate action without a meeting by
less than unanimous written consent shall be given to those stockholders who
have not consented in writing.

                                   ARTICLE III

                                    DIRECTORS

      SECTION 1. NUMBER AND TERM.--The number of directors shall be one (1). The
director shall be elected at the annual meeting of the stockholders and such
director shall be elected to serve until his or her successor shall be elected
and shall qualify. The Director need not be a stockholder.

      SECTION 2. RESIGNATIONS.--Any director, member of a committee or other
officer may resign at any time. Such resignation shall be made in writing, and
shall take effect at the time specified therein, and if no time be specified, at
the time of its receipt by the President or Secretary. The acceptance of a
resignation shall not be necessary to make it effective.

      SECTION 3. VACANCIES.--If the office of any director, member of a
committee or other officer becomes vacant, the remaining directors in office,
though less than a quorum by a majority vote, may appoint any qualified person
to fill such vacancy, who shall hold office for the unexpired term and until his
successor shall be duly chosen.


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      SECTION 4. REMOVAL.--Except as hereinafter provided, any director or
directors may be removed either for or without cause at any time by the
affirmative vote of the holders of a majority of all the shares of stock
outstanding and entitled to vote, at a special meeting of the stockholders
called for the purpose and the vacancies thus created may be filled, at the
meeting held for the purpose of removal, by the affirmative vote of a majority
in interest or the stockholders entitled to vote.

      Unless the Certificate of Incorporation otherwise provides, stockholders
may effect removal of a director who is a member of a classified Board of
Directors only for cause. If the Certificate of Incorporation provides for
cumulative voting and if less than the entire board is to be removed, no
director may be removed without cause if the votes cast against his removal
would be sufficient to elect him if then cumulatively voted at an election of
the entire board of directors, or, if there be classes of directors, at an
election of the class or directors of which he is a part.

      If the holders of any class or series are entitled to elect one or more
directors by the provisions of the Certificate of Incorporation, these
provisions shall apply, in respect to the removal without cause of a director or
directors so elected, to the vote of the holders of the outstanding shares of
that class or series and not to the vote of the outstanding shares as a whole.

      SECTION 5. INCREASE OF NUMBER.--The number of directors may be increased
by amendment of these By-Laws by the affirmative vote of a majority of the
directors, though less than a quorum, or, by the affirmative vote of a majority
in interest of the stockholders, at the annual meeting or at a special meeting
called for that purpose, and by like vote the additional directors may be chosen
at such meeting to hold office until the next annual election and until their
successors are elected and qualify.

      SECTION 6. POWERS.--The Board of Directors shall exercise all of the
powers of the corporation except such as are by law, or by the Certificate of
Incorporation of the corporation or by these By-Laws conferred upon or reserved
to the stockholders.

      SECTION 7: COMMITTEES.--The Board of Directors may, by resolution or
resolutions passed by a majority of the whole board, designate one or more
committees, each committee to consist of two or more of the directors of the
corporation. The board may designate one or more directors as alternate members
of any committee, who may replace any absent or


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disqualified member at any meeting of the committee. In the absence or
disqualification of any member of such committee or committees, the member or
members thereof present at any meeting and not disqualified from voting, whether
or not he or they constitute a quorum, may unanimously appoint another member of
the Board of Directors to act at the meeting in the place of any such absent or
disqualified member.

      Any such committee, to the extent provided in the resolution of the Board
of Directors, or in these By-Laws, shall have and may exercise all the powers
and authority of the Board of Directors in the management of the business and
affairs of the corporation, and may authorize the seal of the corporation to be
affixed to all papers which may require it; but no such committee shall have the
power or authority in reference to amending the Certificate of Incorporation,
adopting an agreement of merger or consolidation, recommending to the
stockholders the sale, lease or exchange of all or substantially all of the
corporation's property and assets, recommending to the stockholders a
dissolution of the corporation or a revocation of a dissolution, or amending the
By-Laws of the corporation; and, unless the resolution, these By-Laws or the
Certificate of Incorporation expressly so provide, no such committee shall have
the power or authority to declare a dividend or to authorize the issuance of
stock.

      SECTION 8. MEETINGS.--The newly elected directors may hold their first
meeting for the purpose of organization and the transaction of business, if a
quorum be present, immediately after the annual meeting of the stockholders; or
the time and place of such meeting may be fixed by consent in writing of all the
directors.

      Regular meetings of the directors may be held without notice at such
places and times as shall be determined from time to time by resolution of the
directors.

      Special meetings of the board may be called by the President or by the
Secretary on the written request of any two directors on at least two days'
notice to each director and shall be held at such place or places as may be
determined by the directors, or as shall be stated in the call of the meeting.

      Unless otherwise restricted by the Certificate of Incorporation or these
By-Laws, members of the Board of Directors, or any committee designated by the
Board of Directors, may participate in a meeting of the Board of Directors, or
any committee, by means of conference telephone or similar communications
equipment by means of which all persons participating in the meeting can hear
each other, and such participation in a meeting shall constitute presence in
person at the meeting.


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      SECTION 9. QUORUM.--A majority of the directors shall constitute a quorum
for the transaction of business. If at any meeting of the board there shall be
less than a quorum present, a majority of those present may adjourn the meeting
from time to time until a quorum is obtained, and no further notice thereof need
be given other than by announcement at the meeting which shall be so adjourned.

      SECTION 10. COMPENSATION.--Directors shall not receive any stated salary
for their services as directors or as members of committees, but by resolution
of the board a fixed fee and expenses of attendance may be allowed for
attendance at each meeting. Nothing herein contained shall be construed to
preclude any director from serving the corporation in any other capacity as an
officer, agent or otherwise, and receiving compensation therefor.

      SECTION 11. ACTION WITHOUT MEETING.--Any action required or permitted to
be taken at any meeting of the Board of Directors, or of any committee thereof,
may be taken without a meeting, if prior to such action a written consent
thereto is signed by all members of the board, or of such committee as the case
may be, and such written consent is filed with the minutes of proceedings of the
board or committee.

                                   ARTICLE IV

                                    OFFICERS

      SECTION 1. OFFICERS.--The officers of the corporation shall be a
President, a Treasurer, and a Secretary, all of whom shall be elected by the
Board of Directors and who shall hold office until their successors are elected
and qualified. In addition, the Board of Directors may elect a Chairman, one or
more Vice-Presidents and such Assistant Secretaries and Assistant Treasurers as
they may deem proper. None of the officers of the corporation need be directors.
The officers shall be elected at the first meeting of the Board of Directors
after each annual meeting. More than two offices may be held by the same person.

      SECTION 2. OTHER OFFICERS AND AGENTS.--The Board of Directors may appoint
such other officers and agents as it may deem advisable, who shall hold their
offices for such terms and shall exercise such powers and perform such duties as
shall be determined from time to time by the Board of Directors.


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      SECTION 3. CHAIRMAN.--The Chairman of the Board of Directors, if one be
elected shall preside at all meetings of the Board of Directors and he shall
have and perform such other duties as from time to time may be assigned to him
by the Board of Directors.

      SECTION 4. PRESIDENT.--The President shall be the chief executive officer
of the corporation and shall have the general powers and duties of supervision
and management usually vested in the office of President of a corporation. He
shall preside at all meetings of the stockholders if present thereat, and in the
absence or non-election of the Chairman of the Board of Directors, at all
meetings of the Board of Directors, and shall have general supervision,
direction and control of the business of the corporation. Except as the Board of
Directors shall authorize the execution thereof in some other manner, he shall
execute bonds, mortgages and other contracts in behalf of the corporation, and
shall cause the seal to be affixed to any instrument requiring it and when so
affixed the seal shall be attested by the signature of the Secretary or the
Treasurer or an Assistant Secretary or an Assistant Treasurer.

      SECTION 5. VICE-PRESIDENT.--Each Vice-President shall have such powers and
shall perform such duties as shall be assigned to him by the directors.

      SECTION 6. TREASURER.--The Treasurer shall have the custody of the
corporate funds and securities and shall keep full and accurate account of
receipts and disbursements in books belonging to the corporation. He shall
deposit all moneys and other valuables in the name and to the credit of the
corporation in such depositaries as may be designated by the Board of Directors.

      The Treasurer shall disburse the funds of the corporation as may be
ordered by the Board of Directors, or the President, taking proper vouchers for
such disbursements. He shall render to the President and Board of Directors at
the regular meetings of the Board of Directors, or whenever they may request it,
an account of all his transactions as Treasurer and of the financial condition
of the corporation. If required by the Board of Directors, he shall give the
corporation a bond for the faithful discharge of his duties in such amount and
with such surety as the board shall prescribe.

      SECTION 7. SECRETARY.--The Secretary shall give, or cause to be given,
notice of all meetings of stockholders and directors, and all other notices
required by law or by these ByLaws, and in case of his absence or refusal or
neglect so to do, any such notice may be given by any person thereunto


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directed by the President, or by the directors, or stockholders, upon whose
requisition the meeting is called as provided in these By-Laws. He shall record
all the proceedings of the meetings of the corporation and of the directors in a
book to be kept for that purpose, and shall perform such other duties as may be
assigned to him by the directors or the President. He shall have custody of the
seal of the corporation and shall affix the same to all instruments requiring
it, when authorized by the directors or the President, and attest the same.

      SECTION 8. ASSISTANT TREASURERS AND ASSISTANT SECRETARIES.--Assistant
Treasurers and Assistant Secretaries, if any, shall be elected and shall have
such powers and shall perform such duties as shall be assigned to them,
respectively, by the directors.

                                    ARTICLE V

                                  MISCELLANEOUS

      SECTION 1. CERTIFICATES OF STOCK.--Certificate of stock, signed by the
Chairman or Vice Chairman of the Board of Directors, if they be elected,
President or Vice-President, and the Treasurer or an Assistant Treasurer, or
Secretary or an Assistant Secretary, shall be issued to each stockholder
certifying the number of shares owned by him in the corporation. Any of or all
the signatures may be facsimiles.

      SECTION 2. LOST CERTIFICATES.--A new certificate of stock may be issued in
the place of any certificate theretofore issued by the corporation, alleged to
have been lost or destroyed, and the directors may, in their discretion, require
the owner of the lost or destroyed certificate, or his legal representatives, to
give the corporation a bond, in such sum as they may direct, not exceeding
double the value of the stock, to indemnify the corporation against any claim
that may be made against it on account of the alleged loss of any such
certificate, or the issuance of any such new certificate.

      SECTION 3. TRANSFER OF SHARES.--The shares of stock of the corporation
shall be transferable only upon its books by the holders thereof in person or by
their duly authorized attorneys or legal representatives, and upon such transfer
the old certificates shall be surrendered to the corporation by the delivery
thereof to the person in charge of the stock and transfer books and ledgers, or
to such other person as the directors may designate, by whom they shall be
cancelled, and new certificates shall thereupon be issued. A record shall be
made of each transfer and whenever a transfer shall be made for collateral
security, and not absolutely, it shall be so expressed in the entry of the
transfer.


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      SECTION 4. STOCKHOLDERS RECORD DATE.--In order that the corporation may
determine the stockholders entitled to notice of or to vote at any meeting of
stockholders or any adjournment thereof, or to express consent to corporate
action in writing without a meeting, or entitled to receive payment of any
dividend or other distribution or allotment of any rights, or entitled to
exercise any rights in respect of any change, conversion or exchange of stock or
for the purpose of any other lawful action, the Board of Directors may fix, in
advance, a record date, which shall not be more than sixty nor less than ten
days before the date of such meeting, nor more than sixty days prior to any
other action. A determination of stockholders of record entitled to notice of or
to vote at a meeting of stockholders shall apply to any adjournment of the
meeting; provided, however, that the Board of Directors may fix a new record
date for the adjourned meeting.

      SECTION 5. DIVIDENDS.--Subject to the provisions of the Certificate of
Incorporation, the Board of Directors may, out of funds legally available
therefor at any regular or special meeting, declare dividends upon the capital
stock of the corporation as and when they deem expedient. Before declaring any
dividend there may be set apart out of any funds of the corporation available
for dividends, such sum or sums as the directors from time to time in their
discretion deem proper for working capital or as a reserve fund to meet
contingencies or for equalizing dividends or for such other purposes as the
directors shall deem conducive to the interests of the corporation.

      SECTION 6. SEAL.--The corporate seal shall be circular in form and shall
contain the name of the corporation, the year of its creation and the words
"CORPORATE SEAL DELAWARE." Said seal may be used by causing it or a facsimile
thereof to be impressed or affixed or reproduced or otherwise.

      SECTION 7. FISCAL YEAR.--The fiscal year of the corporation shall be
determined by resolution of the Board of Directors.

      SECTION 8. CHECKS.--All checks, drafts or other orders for the payment of
money, notes or other evidences of indebtedness issued in the name of the
corporation shall be signed by such officer or officers, agent or agents of the
corporation, and in such manner as shall be determined from time to time by
resolution of the Board of Directors.


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      SECTION 9. NOTICE AND WAIVER OF NOTICE.--Whenever any notice is required
by these By-Laws to be given, personal notice is not meant unless expressly so
stated, and any notice so required shall be deemed to be sufficient if given by
depositing the same in the United States mail, postage prepaid, addressed to the
person entitled thereto at his address as it appears on the records of the
corporation, and such notice shall be deemed to have been given on the day of
such mailing. Stockholders not entitled to vote shall not be entitled to receive
notice of any meetings except as otherwise provided by Statute.

      Whenever any notice whatever is required to be given under the provisions
of any law, or under the provisions of the Certificate of Incorporation of the
corporation or these By-Laws, a waiver thereof in writing, signed by the person
or persons entitled to said notice, whether before or after the time stated
therein, shall be deemed equivalent thereto.

                                   ARTICLE VI

                                   AMENDMENTS

      These By-Laws may be altered or repealed and By-Laws may be made at any
annual meeting of the stockholders or at any special meeting thereof if notice
of the proposed alteration or repeal or By-Law or By-Laws to be made be
contained in the notice of such special meeting, by the affirmative vote of a
majority of the stock issued and outstanding and entitled to vote thereat, or by
the affirmative vote of a majority of the Board of Directors, at any regular
meeting of the Board of Directors, or at any special meeting of the Board of
Directors, if notice of the proposed alteration or repeal, or By-Law or By-Laws
to be made, be contained in the notice of such special meeting.


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