49 U.S.C. § 44101 - Operation of aircraft

(1) when authorized under section 40103 (d) or 41703 of this title;

(2) when it is an aircraft of the national defense forces of the United States and is identified in a way satisfactory to the Administrator of the Federal Aviation Administration; and

(3) for a reasonable period of time after a transfer of ownership, under regulations prescribed by the Administrator.