Code of Federal Regulations Title 19. Customs Duties § 19.122.41 Aircraft required to enter

(a) Public and private aircraft;

(b) Aircraft chartered by, and transporting only cargo that is the property of, the U.S. Department of Defense (DoD), where the DoD–chartered aircraft is manned entirely by the civilian crew of the air carrier under contract to DoD;  and

(c) Aircraft traveling from airport to airport in the U.S. under subpart I, relating to residue cargo procedures.