An airport is a facility at which aircraft take off, land, and can be stored and maintained. The main features of an airport are usually a runway, helicopter pad, or water (for aircraft equipped for water landing and take-off), and they usually include service buildings such as hangars, terminals, and control towers.
Smaller airports are meant for light, private aircraft and can be just a large grass strip to land and take off airplanes, while large, commercial airports can have many square miles of property with several runways, large terminals, air traffic control towers, maintenance hangars, and radar facilities. Each airport may have a specific type of aircraft that it caters to, while others can accommodate all types of aviation.
Small, private airports make up the majority of airports in the country. These are for privately owned and operated aircraft, such as single- or twin-engine, propeller-driven planes or light helicopters. Some of these airports offer private pilot training or air charter services, and many have their own mechanics to take care of the planes on the flight line. These airports are usually not big enough to land jets or airliners, as the runway must have a much longer length for these larger aircraft. Also, small airports may only be able to accommodate one type of aircraft, such as a heliport that has no runway but only on helicopter landing pads.
Large, commercial airports are for big airliners and a large volume of passengers. These airports are quite large and have extremely long runways, their own radar stations, a fleet of aircraft, and numerous ground personnel to manage all the duties there. Large airports may have multiple runways and can land and take off aircraft of almost every size.
Military airports, also known as airbases or air stations, are run by a branch of the military. These airports are generally off-limits to commercial and civilian aircraft unless the plane has a dire emergency and there is no other option but to land there.