19 CFR § 148.61 - Status as crewmembers.
The following persons arriving in the United States shall not be treated as crewmembers:
(a) Members of the uniformed services of the United States and persons in the civil service of the United States engaged in the operation of a vessel, vehicle, or aircraft owned by, or under the complete control and management of, the United States or any of its agencies.
(b) Persons engaged in the operation of a private or public aircraft.
(c) Persons not connected with the operation, navigation, ownership, or business of a vessel, vehicle or aircraft engaged in international traffic.