Airports often have facilities to store and maintain aircraft, and a control tower.
An airport consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface such as a runway for a plane to take off or a helipad, and often includes adjacent utility buildings such as control towers, hangars and terminals.
An airport with a helipad for rotorcraft but no runway is called a heliport.
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 immigration.