Airports are sites where aircraft take off and land and where passengers, baggage and freight are transferred between air and ground transport. They range from large international hubs serving scheduled and charter flights to regional airports, smaller airfields and facilities used mainly for business aviation, training or cargo. Their operators maintain runways, taxiways, aprons and terminals, and coordinate aircraft movements, ground handling and other services needed for flights to operate. Passenger facilities commonly include check-in areas, security screening, departure and arrival halls, baggage handling, toilets, seating and information points. Larger airports may also have shops, food outlets, lounges, car parks and public transport links. Depending on the site, businesses and services based at an airport can include airlines, aircraft maintenance providers, cargo handlers, flight schools, car hire operators and aviation support services.