The aviation system is everything that allows us to fly. The ultimate users are the public, passengers and shippers. The ultimate purpose is transport of passengers and products safely, securely, and efficiently. The aviation system is part of a larger system that also serves the emerging commercial space transportation industry.
Most air transport is provided by private airlines who serve passengers, shippers, or both.
Manufacturing businesses such as Boeing build the aircraft and equipment. The airlines hire pilots, maintenance technicians, cabin crews, airport personnel, and others who directly serve air travelers and shippers. Airports are locally or regionally owned, and a host of people and businesses provide services ranging from parking and limousine service to shops and restaurants. But that is just commercial aviation. General aviation is an important part of the aviation system.