EXHIBIT 3.21

                            ARTICLES OF INCORPORATION

                                       OF

                               FIFTEEN PAC COMPANY

                  KNOW ALL MEN BY THESE PRESENTS: That I, the undersigned, for
         the purpose of forming a corporation under the laws of the State of
         Nevada, do certify:

                                    ARTICLE I

                  The name of the corporation is: FIFTEEN PAC COMPANY

                                   ARTICLE II

                  The principal place of business of this Corporation shall be:
         1325 Airmotive Way, Suite 100, Reno, Nevada 89502.

                                   ARTICLE III

                  The corporation's resident agent shall be: The Corporation
         Trust Company of Nevada, One East First Street, Reno, Nevada 89501.

                                   ARTICLE IV

                  The nature of the business and the objects and purposes to be
         transacted, promoted, [ILLEGIBLE] carried on by the corporation are to
         engage in any lawful act or activity for which corporations may be
         organized under the General Corporation Law of Nevada.



                                    ARTICLE V

         The corporation shall have authority to issue the following:

                           The number of shares of common stock which this
                  corporation is authorized to issue is One Hundred Thousand
                  (100,000) shares with a par value of One Cent ($.01) per
                  share.

                                   ARTICLE VI

         The Board of Directors shall consist of one (1) to nine (9)
individuals, as determined by resolution of the Board of Directors. The initial
Board of Directors shall consist of one person, who shall serve as Director
until the annual meeting of shareholders or until his successor is elected and
qualified. Such person shall be Charles J. Bayer, 2721 N. Central Avenue,
Phoenix, Arizona 85004.

                                     ARTICLE VII

         The name and address of the incorporator is:

                      Jennifer M. Settles
                      2721 N. Central Avenue, 11th Floor
                      Phoenix, Arizona 85003

                                  ARTICLE VIII

         The period of existence of the Corporation shall be perpetual.

                                   ARTICLE IX

         The corporation shall indemnify, to the fullest extent authorized or
permitted by law, as the same exists or may hereafter be amended, any person
made, or threatened to

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be made, a defendant or witness to any threatened, pending or completed action,
suit, or proceeding (whether civil, criminal, administrative, investigative or
otherwise) by reason of the fact that he or she, or his or her testator or
intestate, is or was a director or officer of the corporation or by reason of
the fact that such director or officer, at the request of the corporation, is or
was serving any other corporation, partnership, joint venture, trust, employee
benefit plan, or other enterprise. Nothing contained herein shall diminish any
rights to indemnification to which employees or agents other than directors or
officers may be entitled by law, and the corporation may indemnify such
employees and agents to the fullest extent and in the manner permitted by law.
The rights to indemnification set forth in this Article shall not be exclusive
of any other rights to which any person may be entitled under any statute,
provision of the Articles of Incorporation, Bylaw, agreement, contract, vote of
shareholders or directors, or as otherwise provided.

In furtherance and not in limitation of the powers conferred by statute:

         1. The corporation may purchase and maintain insurance on behalf of any
person who is or was a director, officer, employee or agent of the corporation,
or is serving in any capacity, at the request of the corporation, any other
corporation, partnership, joint venture, trust, employee benefit plan or other
enterprise, against any liability or expense incurred by him or her in any such
capacity, or arising out of his or her status as such, whether or not the
corporation would have the power to indemnify him or her against such liability
or expense under the provisions of law; and

         2. The corporation may create a trust fund, grant a security interest
or lien on any assets of the corporation and/or use other means (including,
without limitation, letters of

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credit, guaranties, surety bonds and/or other similar arrangements), and enter
into contracts providing indemnification to the full extent authorized or
permitted by law and including as part thereof provisions with respect to any or
all of the foregoing to ensure the payment of such amounts as may become
necessary to effect indemnification as provided therein, or elsewhere.

         No director or officer shall be personally liable to the corporation or
its stockholders for damages for breach of fiduciary duty as a director or
officer, except the liability of a director or officer shall not be limited or
eliminated for: (a) acts or omissions which involve intentional misconduct,
fraud or a knowing violation of law; or (b) the payment of distribution in
violation of Nevada Revised Statutes Section 78.300.

         IN WITNESS WHEREOF, I, the aforementioned incorporator, have signed the
Articles of Incorporation this 11th day of August, 1999.

                                       /s/ Jennifer M. Settles
                                       -----------------------------------------
                                       Jennifer M. Settles, Incorporator

STATE OF ARIZONA    )
                    )
COUNTY OF MARICOPA  )

         I, Nancy K. Ventre, the undersigned authority, a Notary Public in and
for said County in said State, hereby certify that on the 11th day of August,
1999 before me personally appeared, Jennifer M. Settles, who is the person named
in and who executed the foregoing Articles of Incorporation and who is known to
me, executed the same as

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Incorporator and with full authority, executed the same voluntarily for and as
the act of said corporation.

         IN TESTIMONY WHEREOF, I have hereunto set my hand and affixed my
official seal this 11th day of August, 1999.

                                         /s/ Nancy K. Ventre
                                         -----------------------
                                         NOTARY PUBLIC
                                         My Commission Expires: 8/19/99

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