14 CFR § 91.147 - Passenger carrying flights for compensation or hire.
Each Operator conducting passenger-carrying flights for compensation or hire must meet the following requirements unless all flights are conducted under § 91.146.
(a) For the purposes of this section and for drug and alcohol testing, Operator means any person conducting nonstop passenger-carrying flights in an airplane or helicopter for compensation or hire in accordance with §§ 119.1(e)(2), 135.1(a)(5), or 121.1(d), of this chapter that begin and end at the same airport and are conducted within a 25-statute mile radius of that airport.
(b) An Operator must comply with the safety provisions of part 136, subpart A of this chapter, and apply for and receive a Letter of Authorization from the responsible Flight Standards office.
(c) Each application for a Letter of Authorization must include the following information:
(1) Name of Operator, agent, and any d/b/a (doing-business-as) under which that Operator does business;
(2) Principal business address and mailing address;
(3) Principal place of business (if different from business address);
(4) Name of person responsible for management of the business;
(6) Type of aircraft, registration number(s), and make/model/series; and
(7) An Antidrug and Alcohol Misuse Prevention Program registration.
(d) The Operator must register and implement its drug and alcohol testing programs in accordance with part 120 of this chapter.
(e) The Operator must comply with the provisions of the Letter of Authorization received.