All modes of transportation have certain common features. They require an infrastructure, terminals, vehicles as mean of transportation and operations to control the transportation system. In the airline industry the 'transport networks' are referred to as 'Airways' and the terminal as the 'Airports.' The 'vehicles' used are 'different types of airplanes. 'Air Traffic Control (ATC)' refers to a service offered by the appropriate authority to promote the safe, orderly, flow of air traffic.