49 C.F.R. § 1544.201 : Transportation — OTHER REGULATIONS RELATING TO TRANSPORTATION — TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY — CIVIL AVIATION SECURITY — AIRCRAFT OPERATOR SECURITY: AIR CARRIERS AND COMMERCIAL OPERATORS — OPERATIONS — Acceptance and screening of individuals and accessible property

(a) Preventing or deterring the carriage of any explosive, incendiary, or deadly or dangerous weapon. Each aircraft operator must use the measures in its security program to prevent or deter the carriage of any weapon, explosive, or incendiary 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 aircraft operator 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 §1544.207.
(c) Refusal to transport. Each aircraft operator must deny entry into a sterile area and must refuse to transport-
(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) 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) Prohibitions on carrying a weapon, explosive, or incendiary. Except as provided in §§1544.219, 1544.221, and 1544.223, no aircraft operator may permit any individual to have a weapon, explosive, or incendiary, on or about the individual's person or accessible property when onboard an aircraft.
(e) Staffing. Each aircraft operator must staff its security screening checkpoints with supervisory and non-supervisory personnel in accordance with the standards specified in its security program.

49 C.F.R. § 1544.201