29 C.F.R. § 783.18
Prior to the 1961 Amendments, the Fair Labor Standards Act applied to all employees, not specifically exempted, who are engaged (a) in interstate or foreign commerce or (b) in the production of goods for such commerce, which is defined to include any closely related process or occupation directly, essential to such production (29 U.S.C. 206(a) , 207(a) ; and see §§ 783.12 to 783.15 for definitions governing the scope of this coverage). The Act as amended in 1961 continues this coverage. In general, employees of businesses concerned with the transportation of goods or persons on navigable waters are engaged in interstate or foreign commerce, or in the production of goods for such commerce, as defined in the Act, and are subject to the Act's provisions except as otherwise provided in sections 13(a)(14) and 13(b)(6) or other express exemptions. A detailed discussion of the activities in commerce or in the production of goods for commerce which will bring an employee under the Act is contained in part 776 of this chapter, dealing with general coverage.
29 C.F.R. §783.18