Wikipedia
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport. An airport consists of at least one surface such as a runway, a helipad, or water for takeoffs and landings, and often includes buildings such as hangars and terminal buildings.
Larger airports may have fixed base operator services, seaplane docks and ramps, air traffic control, passenger facilities such as restaurants and lounges, and emergency services. A military airport is known as an airbase or air station. The terms airfield, airstrip, and aerodrome may also be used to refer to airports, and the terms heliport, seaplane base, and STOLport refer to airports dedicated exclusively to helicopters, seaplanes, or short takeoff and landing aircraft. In some jurisdictions, the term airport is used where the facility is licensed as such by the relevant government organization (e.g. the U.S. Federal Aviation Administration (FAA), Transport Canada). Elsewhere the distinction is one of general appearance. Other jurisdictions define an airport by its having the customs offices etc expected of a port, though the more general term is airport of entry.
Attributes
Smaller or less-developed airports — which represent the vast majority — often have a single runway shorter than 1,000 m (3,300 ft). Larger airports for airline flights generally have paved runways 2,000 m (6,600 ft) or longer. Many small airports have dirt, grass, or gravel runways, rather than asphalt or concrete.
In the United States, the minimum dimensions for dry, hard landing fields are defined by the FAR Landing And Takeoff Field Lengths. These include considerations for safety margins during landing and takeoff. Heavier aircraft require longer runways.
The longest public-use runway in the world is at Qamdo Bangda Airport in China. It has a length of 5,500 m (18,045 ft). The worlds widest paved ru read more at » http://en.wikipedia.org/wiki/Airport