An airport with a helipad for rotorcraft but no runway is called a heliport. An airport for use by seaplanes and amphibious aircraft is called a seaplane base. Such a base typically includes a stretch of open water for takeoffs and landings, and seaplane docks for tying-up.
An international airport has additional facilities for customs and passport control as well as incorporating all of the aforementioned elements above. Such airports rank among the most complex and largest of all built typologies with 15 of the top 50 buildings by floor area being airport terminals.
In warfare, airports can become the focus of intense fighting, for example the Battle of Tripoli Airport or the Battle for Donetsk Airport, both taking place in 2014. An aerodrome primarily for military use is called an airbase (or "Air Base") or air station.
The majority of the world's airports are non-towered, with no air traffic control presence. Busy airports have air traffic control (ATC) system. All airports use a traffic pattern to assure smooth traffic flow between departing and arriving aircraft. There are a number of aids available to pilots, though not all airports are equipped with them. Many airports have lighting that help guide planes using the runways and taxiways at night or in rain, snow, or fog. In the U.S. and Canada, the vast majority of airports, large and small, will either have some form of automated airport weather station, a human observer or a combination of the two. Air safety is an important concern in the operation of an airport, and airports often have their own safety services.
The terms aerodrome, airfield, and airstrip 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 take-off and landing aircraft.