49 C.F.R. § 1546.201 – Acceptance and screening of individuals and accessible property.

(a) Preventing or deterring the carriage of any explosive, incendiary, or weapon. Unless otherwise authorized by TSA, each foreign air carrier must use the measures in its security program to prevent or deter the carriage of any explosive, incendiary, or weapon on or about each individual's person or accessible property before boarding an aircraft or entering a sterile area.
(b) Screening of individuals and accessible property. Except as provided in its security program, each foreign air carrier must ensure that each individual entering a sterile area at each preboard screening checkpoint for which it is responsible, and all accessible property under that individual's control, are inspected for weapons, explosives, and incendiaries as provided in § 1546.207.
(c) Refusal to transport. Each foreign air carrier conducting an operation for which a security program is required by § 1546.101(a), (b), or (c) must refuse to transport—
1. (1) Any individual who does not consent to a search or inspection of his or her person in accordance with the system prescribed in this part; and
2. (2) Any property of any individual or other person who does not consent to a search or inspection of that property in accordance with the system prescribed by this part.
(d) Explosive, incendiary, weapon: Prohibitions and exceptions. No individual may, while on board an aircraft being operated by a foreign air carrier in the United States, carry on or about his person a deadly or dangerous weapon, either concealed or unconcealed. This paragraph (d) does not apply to—
1. (1) Officials or employees of the state of registry of the aircraft who are authorized by that state to carry arms; and
2. (2) Crewmembers and other individuals authorized by the foreign air carrier to carry arms.