International Air Transport Association airport code
An IATA airport code, also known an IATA location identifier, IATA station code or simply a location identifier, is a three-letter code designating many airports around the world, defined by the International Air Transport Association (IATA). The characters prominently displayed on baggage tags attached at airport check-in desks are an example of a way these codes are used.
IATA also provides codes for railway stations and for airport handling entities. A list of airports sorted by IATA code is available. A list of railway stations codeshared in agreements between airlines and rail lines such as Amtrak, SNCF French Rail, and Deutsche Bahn is available. There is also a separate List of Amtrak station codes, three-character codes used by Amtrak for its railway stations in the United States and Canada.
- See also: List of airports by ICAO code
History and conventions
Airport codes arose out of the convenience that it brought pilots for location identification in the 1930s. Initially, pilots in the United States used the two-letter code from the National Weather Service (NWS) for identifying cities. This system became unmanageable for cities and towns without an NWS identifier, thus a three-letter system of airport codes was implemented. This system allowed for 17,576 permutations, assuming all letters can be used in conjunction with each other.
Generally speaking, airport codes are named after the first three letters of the city in which it is located - ATL for Atlanta, SIN for Singapore, MEX for Mexico City, IST for Istanbul; or a combination of the letters in its name, EWR for Newark, GDL for Guadalajara, JNB for Johannesburg, HKG for Hong Kong, SLC for Salt Lake City and WAW for Warsaw. Some airports in the United States retained their NWS codes and simply appended an X at the end, such as LAX for Los Angeles, PDX for Portland, and PHX for Phoenix.
For many reasons, some airport codes do not fit the normal scheme described above. Some airports, for example, cross several municipalities or regions, and mix the letters around, giving rise to DFW for Dallas–Fort Worth, DTW for Detroit–Wayne County, RDU for Raleigh–Durham, MSP for Minneapolis–St. Paul and LBA for Leeds Bradford (Airport).
Large metropolitan areas with more than one airport often resort to codes named after the airport itself instead of the city it serves. Often, another code is reserved which refers to the city itself. For instance:
- Buenos Aires (BUE) — Ezeiza (EZE) is named after the suburb in Ezeiza Partido which the airport is located, while the city also has another airport in city proper, Aeroparque Jorge Newbery (AEP).
- Chicago (CHI) — O'Hare (ORD), named after Orchard Field, the airport's former name which took it, and Midway (MDW)
- Jakarta (JKT) — Soekarno-Hatta (CGK) is named after Cengkareng, the district in which the airport is located, while the city also has another airport, Halim Perdanakusuma (HLP). JKT had referred to the city's former airport, Kemayoran Airport which is now closed.
- London (LON) — Heathrow (LHR), Gatwick (LGW), London City (LCY), Stansted (STN), Luton (LTN) and Southend (SEN)
- Milan (MIL) – Malpensa (MXP), Linate (LIN) and Bergamo-Orio al Serio (BGY)
- Montreal (YMQ) – Trudeau (YUL), Mirabel (YMX), and Saint-Hubert (YHU)
- Moscow (MOW) — Sheremetyevo (SVO), Domodedovo (DME), Vnukovo (VKO)
- New York City (NYC) — John F. Kennedy (JFK, formerly Idlewild (IDL)), La Guardia (LGA), and Newark Liberty (EWR)
- Osaka (OSA) – Kansai (KIX) and Itami (ITM, formerly OSA)
- Paris (PAR) — Orly (ORY), Charles de Gaulle (CDG) and Beauvais–Tillé Airport (BVA)
- Rio de Janeiro (RIO) — Galeão (GIG) and Santos Dumont (SDU)
- Rome (ROM) — Fiumicino (FCO) and Ciampino (CIA)
- São Paulo (SAO) — Congonhas (CGH), Guarulhos (GRU) and Campinas (VCP)
- Seoul (SEL) — Incheon (ICN) and Gimpo (GMP, formerly SEL)
- Stockholm (STO) — Arlanda (ARN), Bromma (BMA) and Västerås (VST)
- Tokyo (TYO) — Haneda (HND) and Narita (NRT)
- Toronto (YTO) — Pearson (YYZ), Bishop (YTZ) and Buttonville (YKZ)
- Washington, D.C. (WAS) — Dulles (IAD), Reagan-National (DCA), and Baltimore-Washington (BWI)
When different cities with the same name each have an airport, the airports need to be assigned different codes. For example, Norman Y. Mineta San Jose International Airport (SJC), is in San Jose, California, United States and Juan Santamaría International Airport (SJO) is in San José, Costa Rica.
Sometimes, a new airport is built, replacing the old one, leaving the city's new "major" airport code to no longer correspond with the city's name. This is in conjunction to rules aimed to avoid confusion, which state that "the first and second letters or second and third letters of an identifier may not be duplicated with less than 200 nautical miles separation." Thus, Washington D.C.-area's three airports all have radically different codes: IAD for Washington-Dulles), DCA for Reagan National (District of Columbia Airport), and BWI for Baltimore (Baltimore–Washington International, formerly BAL). Since HOU is used for William P. Hobby Airport, the new Houston-Intercontinental became IAH. The code BKK was originally assigned to Bangkok-Don Mueang and was later transferred to Suvarnabhumi Airport, while the former adopted DMK. Shanghai-Hongqiao retained the code SHA, while the newer Pudong Airport adopted PVG. The opposite is true for Berlin, the international airport Berlin-Tegel uses the code TXL, while its smaller counterpart Berlin-Schönefeld uses SXF; the new Berlin Brandenburg Airport is going to have the code BER.
Since the US Navy reserved "N" codes and the Federal Communications Commission has reserved rights for "W" and "K", certain U.S. cities which begin with these letters had to adopt "irregular" airport codes: EWR for Newark, ORF for Norfolk, Virginia, EYW for Key West, Florida, and APC for Napa, California. This "rule" does not apply outside of the United States: Karachi is KHI, Warsaw is WAW, Nagoya is NGO. In addition, since "Q" was used for international communications, cities with "Q" beginning their name also had to find alternate codes, as in the case of Qiqihar (NDG), Quetta (UET) and Quito (UIO).
IATA codes should not be confused with the FAA identifiers of US airports. Most FAA identifiers agree with the corresponding IATA codes, but some do not, such as Saipan whose FAA identifier is GSN and its IATA code SPN, and some coincide with IATA codes of non-US airports.
Many cities retain historical names in their airport codes despite the fact that their official name is now different. This is especially prominent in India: BOM for Mumbai (formerly Bombay), CCU for Kolkata (formerly Calcutta), and MAA for Chennai (formerly Madras); in China: CAN for Guangzhou (formerly Canton), PEK for Beijing (formerly Peking), and TAO for Qingdao (formerly Tsingtao). Similarly, this is the case with FRU for Bishkek (formerly Frunze), LED for St. Petersburg (formerly Leningrad), GOJ for Nizhny Novgorod (formerly Gorky), SGN for Ho Chi Minh City (formerly Saigon), and TGD for Podgorica (formerly Titograd).
Some airport codes are based on previous names associated with a present airport, such as Chicago's O'Hare, which is assigned ORD, based on its old name of Orchard Field, before it was expanded and renamed O'Hare in the mid-1950s. Similarly, Orlando International Airport uses MCO, based on the old McCoy Air Force Base, which was converted to joint civilian/military use and renamed Orlando Jetport at McCoy in the early 1960s and finally Orlando International in the early 1980s. Other airport codes are similarly not immediately obvious in origin, and each have their own peculiarities. Nashville uses BNA, Knoxville uses TYS, and Kahului (the main gateway into Maui) uses OGG, while Spokane International Airport goes by GEG. Most of these are named after individuals. In Asia, codes that do not correspond with their city's names include Niigata's KIJ, Nanchang's KHN, Zhengzhou's CGO, Pyongyang's FNJ, and Kobe's UKB.
Some airports are identified even in colloquial speech by their airport code. The most notable example is LAX.
All major airports in Canada use airport codes that begin with the letter "Y", although not all "Y" codes are Canadian. Many Canadian airports simply append a combinations of letters in the city's name to the "Y": YOW for Ottawa, YYC for Calgary, and YVR for Vancouver, whereas other Canadian airports simply use the arbitrary letters assigned to them, such as YQX in Gander and YXS in Prince George. While certain codes themselves make it more difficult to identify an airport, some codes have become popular in usage due to the airports, particularly two of Canada's largest airports, YYZ for Toronto-Pearson and YUL for Montreal-Trudeau. Canada's third busiest airport, Calgary International Airport, has begun using its airport code YYC as a marketing brand and name for the airport authority web site (yyc.com). 
Numerous New Zealand airports use codes which contain a letter Z, to distinguish them from similar airport names in other countries. Examples include HLZ for Hamilton, ZQN for Queenstown, and WSZ for Westport.
- IATA Coding Systems
- IATA Airline Coding Directory
- "Airport ABCs: An Explanation of Airport Identifier Codes". Air Line Pilot. Air Line Pilots Association. 1994. Retrieved 6 January 2012.
- Stephenson, Amanda (11 February 2013). "Calgary International surpasses Montreal to become third busiest airport in Canada". Calgary Herald. Retrieved 22 March 2015.
- "YYC: Calgary Airport Authority". Retrieved 22 March 2015.
- IATA official web site
- IATA Airline and Airport Code Search
- United Nations Code for Trade and Transport Locations (UN/LOCODE) - includes IATA codes
- "Airport ABCs: An Explanation of Airport Identifier Codes". Air Line Pilot. Air Line Pilots Association. December 1994.
- Airport IATA/ICAO Designator / Code Database Search (from Aviation Codes Central Web Site - Regular Updates)
- Airport codes from around the world (Searchable IATA, ICAO, FAA codes, etc.)
- Search Airport/Airline by IATA/ICAO code