Within the terminal, passengers purchase tickets, transfer their luggage, and go through security. The buildings that provide access to the airplanes (via gates) are typically called concourses. However, the terms "terminal" and "concourse" are sometimes used interchangeably, depending on the configuration of the airport.
Smaller airports have one terminal while larger airports have several terminals and/or concourses. At small airports, the single terminal building typically serves all of the functions of a terminal and a concourse.
Some larger airports have one terminal that is connected to multiple concourses via walkways, sky-bridges, or underground tunnels (such as Denver International Airport, modeled after Atlanta's, the world's busiest). Some larger airports have more than one terminal, each with one or more concourses (such as New York's John F. Kennedy International Airport). Still other larger airports have multiple terminals each of which incorporate the functions of a concourse (such as Dallas/Fort Worth International Airport).
According to Frommers, most airport terminals are built in a plain style, with the 'concrete boxes of the 1960s and 1970s generally gave way to glass boxes in the 1990s and 2000s, with the best terminals making a vague stab at incorporating ideas of "light" and "air"'. However, some, such as Baghdad International Airport, are monumental in stature, while others are considered architectural masterpieces, such as Terminal 1 at Charles de Gaulle Airport near Paris or Terminal 5 at New York's JFK Airport. A few are designed to reflect the culture of a particular area, some examples being the terminal at Albuquerque International Sunport in New Mexico, which is designed in the Pueblo Revival style popularized by architect John Gaw Meem, as well as the terminal at Bahías de Huatulco International Airport in Huatulco, Oaxaca, Mexico, which features some palapas that are interconnected to form the airport terminal.
Due to the rapid rise in popularity of passenger flight, many early terminals were built in the 1930s-1940s and reflected the popular art deco style architecture of the time. One such surviving example from 1940 is the Houston Municipal Airport Terminal. Early airport terminals opened directly onto the tarmac: passengers would walk or take a bus to their aircraft. This design is still common among smaller airports, and even many larger airports have "bus gates" to accommodate aircraft beyond the main terminal.
A pier design uses a small, narrow building with aircraft parked on both sides. One end connects to a ticketing and baggage claim area. Piers offer high aircraft capacity and simplicity of design, but often result in a long distance from the check-in counter to the gate (up to half a mile in the cases of Kansai International Airport or Lisbon Portela Airport's Terminal 1). Most large international airports have piers, including Chicago's O'Hare International Airport, Larnaca International Airport, Frankfurt International Airport, London Heathrow Airport, Rome Fiumicino Airport, Amsterdam Schiphol Airport, Murtala Muhammed International Airport, Ninoy Aquino International Airport, Kuala Lumpur International Airport, Mérida International Airport, Bangkok International Airport, Mazatlan International Airport, Beirut International Airport, Hong Kong International Airport, Allama Iqbal International Airport, Tijuana International Airport, Toronto-Pearson International Airport, Indira Gandhi International Airport, New Delhi, Salt Lake City International Airport, Fort Lauderdale-Hollywood International Airport, Chhatrapati Shivaji International Airport, Mumbai, Ronald Reagan Washington National Airport and Miami International Airport.
A satellite terminal is a building detached from other airport buildings, so that aircraft can park around its entire circumference. The first airport to use a satellite terminal was London Gatwick Airport. It used an underground pedestrian tunnel to connect the satellite to the main terminal. This was also the first setup at Los Angeles International Airport, but it has since been converted to a pier layout. The first airport to use an automatic people mover to connect the main terminal with a satellite was Tampa International Airport, which is the standard today. Other examples include the following:
Some airports use a semicircular terminal, with aircraft parked on one side and cars on the other. This design results in long walks for connecting passengers, but greatly reduces travel times between check-in and the aircraft. Airports designed around this model include Charles de Gaulle Airport (terminal 2), Chhatrapati Shivaji International Airport, Mumbai ( old terminal 2), Dallas/Fort Worth International Airport, Seoul's Incheon International Airport, Jakarta's Soekarno-Hatta International Airport (terminal 1 & 2), Toronto Pearson Airport, Kansas City Airport, Nairobi's Jomo Kenyatta International Airport, Rio de Janeiro-Galeão International Airport and Sapporo's New Chitose Airport.
One rarer terminal design is the mobile lounge, where passengers are transported from the gate to their aircraft in a large vehicle which docks directly to the terminal and the aircraft. Washington Dulles International Airport, Mexico City International Airport, and Mirabel International Airport have used this design.
A common-use facility or terminal design disallows airlines to have its own proprietary check-in counters, gates and IT systems. Rather, check-in counters and gates can be flexibly reassigned as needed.
With an area of over (1,713,000 m²) and capacity of over 60 million passengers,Dubai International Airport (Terminal 3) in Dubai, United Arab Emirates, became the largest single Terminal building in the world when it opened on October 14, 2008. Other large scale airport terminal buildings with floor area over 500,000 m2 include Terminal 3 of Beijing Capital International Airport (986,000 m2), Hamad International Airport in Doha, Qatar (600,000 m2), main terminal of Incheon International Airport in Seoul (594,000 m2), Terminal 1 of Hong Kong International Airport (570,000 m2), Suvarnabhumi Airport in Bangkok (563,000 m2), Kunming Changshui International Airport (548,300 m2) Terminal 1 of Barcelona Airport, (546,000 square metres), and Terminal 3 of Indira Gandhi International Airport in Delhi, India (502,000 m2).
Many small and mid-size airports have a single two or three-lane one-way loop road which is used by local private vehicles and buses to drop off and pick up passengers.
An international airport may have two grade-separated one-way loop roads, one for departures and one for arrivals. It may have a direct rail connection by regional rail, light rail, or subway to the downtown or central business district of the closest major city. The largest airports may have direct connections to the closest freeway. Airport Transportation for there will be car rental agencies and taxi companies operating around the terminals. The Hong Kong International Airport has ferry piers on the airside for ferry connections to and from mainland China and Macau without passing through Hong Kong immigration controls.