Scheduled air transport includes all passenger and cargo flights that operate on regularly scheduled routes. The larger, scheduled airlines and air carriers that operate in the U.S. as well as worldwide are governed by the FAR – Part 121. As described by the FAR: “Part 121” Operating Requirements: Domestic, Flag, and Supplemental Operations. It is important to note that Part 135 and 121 do not distinguish between type of aircraft used, but rather the type of activity done with the aircraft. In general, Part 121 is more stringent on most aspects of operation than Part 135, though it should be noted that when followed to the letter, as members of ACANA (Air Charter Association of North America) such as Stratos Jets ensure on every flight, the level of safety and efficient operation is quite high. Commercial aviation is the part of civil aviation (both general aviation and scheduled air transport) that involves operating aircraft for hire to transport passengers or cargo. A flight may be operated for money only if it meets three criteria: The pilot must hold a valid commercial pilot’s certificate The aircraft must hold a valid commercial registration The operator must hold a certificate or some other authorization for commercial operations