27 C.F.R. § 31.92
Carriers not engaged in passenger service
Except as otherwise provided in § 31.93, the retailing of liquors on any train, aircraft, boat, or other conveyance that is not engaged in the business of carrying passengers is prohibited.
Except as otherwise provided in § 31.93, the retailing of liquors on any train, aircraft, boat, or other conveyance that is not engaged in the business of carrying passengers is prohibited.