Airports are divided into landside and airside areas. Landside areas include parking lots, public transportation train stations and access roads. Airside areas include all areas accessible to aircraft, including runways, taxiways and ramps. Access from landside areas to airside areas is tightly controlled at most airports. Passengers on commercial flights access airside areas through terminals, where they can purchase tickets, clear security check, or claim luggage and board aircraft through gates. The waiting areas which provide passenger access to aircraft are typically called concourses, although this term is often used interchangeably with terminal. The apron from the top floor observation room, Halifax International Airport, Canada The area where aircraft park next to a terminal to load passengers and baggage is known as a ramp (or "the tarmac"). Parking areas for aircraft away from terminals are called aprons. Airports can be towered or non-towered, depending on air traffic density and available funds. Due to their high capacity and busy airspace, many international airports have air traffic control located on site. Airports with international flights have customs and immigration facilities. However, as some countries have agreements that allow travel between them without customs and immigrations, such facilities are not a definitive need for an international airport. International flights often require a higher level of physical security, although in recent years, many countries have adopted the same level of security for international and domestic travel. Some airport structures include on-site hotels built within or attached to a terminal building. Airport hotels have grown popular due to their convenience for transient passengers and easy accessibility to the airport terminal. Many airport hotels also have agreements with airlines to provide overnight lodging for displaced passengers. "Floating airports" are being designed which could be located out at sea and which would use designs such as pneumatic stabilized platform technology. Products and services[edit] ve may bay vé máy bay tết ve may bay quoc te vé máy bay vé máy bay nội địa dat ve may bay vé máy bay khuyến mãi dai ly ve may bay