Public Law 106-181, codified in Title 49 U.S.C., Chapter 401, Sections 40102(a)(37) and 40125, contains the latest version of the definition of "public aircraft.” This law was signed in April 2000.

 TITLE 49 - TRANSPORTATION
    SUBTITLE VII - AVIATION PROGRAMS
    PART A - AIR COMMERCE AND SAFETY
    subpart i - general
    CHAPTER 401 - GENERAL PROVISIONS

-HEAD-
    Sec. 40102. Definitions

-STATUTE-
      (a) General Definitions. - In this part -

(37) "public aircraft" means any of the following:

 (A) Except with respect to an aircraft described in
        subparagraph (E), an aircraft used only for the United States
        Government, except as provided in section 40125(b).
       

 (B) An aircraft owned by the Government and operated by any
        person for purposes related to crew training, equipment
        development, or demonstration, except as provided in section
        40125(b).

 (C) An aircraft owned and operated by the government of a
        State, the District of Columbia, or a territory or possession
        of the United States or a political subdivision of one of these
        governments, except as provided in section 40125(b).

 (D) An aircraft exclusively leased for at least 90 continuous
        days by the government of a State, the District of Columbia, or
        a territory or possession of the United States or a political
        subdivision of one of these governments, except as provided in
        section 40125(b).

 (E) An aircraft owned or operated by the armed forces or
        chartered to provide transportation to the armed forces under
        the conditions specified by section 40125(c).

    TITLE 49 - TRANSPORTATION
    SUBTITLE VII - AVIATION PROGRAMS
    PART A - AIR COMMERCE AND SAFETY
    subpart i - general
    CHAPTER 401 - GENERAL PROVISIONS

-HEAD-                                                                                                                              01/02/01
    Sec. 40125. Qualifications for public aircraft status

-STATUTE-
      (a) Definitions. - In this section, the following definitions apply:

        (1) Commercial purposes. - The term "commercial purposes"
      means the transportation of persons or property for compensation
      or hire, but does not include the operation of an aircraft by the
      armed forces for reimbursement when that reimbursement is
      required by any federal statute, regulation, or directive, in
      effect on November 1, 1999, or by one government on behalf of
      another government under a cost reimbursement agreement if the
      government on whose behalf the operation is conducted certifies
      to the Administrator of the Federal Aviation Administration that
      the operation is necessary to respond to a significant and
      imminent threat to life or property (including natural resources)
      and that no service by a private operator is reasonably available
      to meet the threat.
        (2) Governmental function. - The term "governmental function"
      means an activity undertaken by a government, such as national
      defense, intelligence missions, firefighting, search and rescue,
      law enforcement (including transport of prisoners, detainees, and
      illegal aliens), aeronautical research, or biological or
      geological resource management.
        (3) Qualified non-crewmember. - The term "qualified
      non-crewmember" means an individual, other than a member of the
      crew, aboard an aircraft -
          (A) operated by the armed forces or an intelligence agency of
        the United States Government; or
          (B) whose presence is required to perform, or is associated
        with the performance of, a governmental function.
        (4) Armed forces. - The term "armed forces" has the meaning
      given such term by section 101 of title 10.
      (b) Aircraft Owned by Governments. - An aircraft described in
    subparagraph (A), (B), (C), or (D) of section 40102(a)(37) does not
    qualify as a public aircraft under such section when the aircraft
    is used for commercial purposes or to carry an individual other
    than a crewmember or a qualified non-crewmember.
      (c) Aircraft Owned or Operated by the Armed Forces. -
        (1) In general. - Subject to paragraph (2), an aircraft
      described in section 40102(a)(37)(E) qualifies as a public
      aircraft if -
          (A) the aircraft is operated in accordance with title 10;
          (B) the aircraft is operated in the performance of a
        governmental function under title 14, 31, 32, or 50 and the
        aircraft is not used for commercial purposes; or
          (C) the aircraft is chartered to provide transportation to
        the armed forces and the Secretary of Defense (or the Secretary
        of the department in which the Coast Guard is operating)
        designates the operation of the aircraft as being required in
        the national interest.
        (2) Limitation. - An aircraft that meets the criteria set forth
      in paragraph (1) and that is owned or operated by the National
      Guard of a State, the District of Columbia, or any territory or
      possession of the United States, qualifies as a public aircraft
      only to the extent that it is operated under the direct control
      of the Department of Defense.

-SOURCE-
    (Added Pub. L. 106-181, title VII, Sec. 702(b)(1), Apr. 5, 2000,
    114 Stat. 155.)
-MISC1-
                               EFFECTIVE DATE
      Section applicable only to fiscal years beginning after Sept. 30,
    1999, see section 3 of Pub. L. 106-181, set out as an Effective
    Date of 2000 Amendments note under section 106 of this title.

-SECREF-
                   SECTION REFERRED TO IN OTHER SECTIONS
      This section is referred to in section 40102 of this title.