Part 91
Small non-commercial aircraft within the United States
Part 121
Large U.S.-based airlines, regional air carriers, and all cargo operators
Part 135
Small single aircraft operators to large operators that often provide a network to move cargo to larger Part 121 air carriers
Part 141
Federal Aviation Administration (FAA)-certificated pilot schools
Part 145
Maintenance facilities that are engaged in the maintenance, inspection, and alteration of aircraft and aircraft products
OEM
Original Equipment Manufacturer
