IATA airport code

[1] The characters prominently displayed on baggage tags attached at airport check-in desks are an example of a way these codes are used.

A list of railway station codes, shared in agreements between airlines and rail lines such as Amtrak, SNCF, and Deutsche Bahn, is available.

Airport codes arose out of the convenience that the practice 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.

[citation needed] Canada's unusual codes—which bear little to no similarity with any conventional abbreviation to the city's name—such as YUL in Montréal, and YYZ in Toronto, originated from the two-letter codes used to identify weather reporting stations in the 1930s.

The result is that most major Canadian airport codes start with "Y" followed by two letters in the city's name (for example, YOW for Ottawa, YWG for Winnipeg, YYC for Calgary, or YVR for Vancouver), whereas other Canadian airports append the two-letter code of the radio beacons that were the closest to the actual airport, such as YQX in Gander or YXS in Prince George.

Examples include HLZ for Hamilton, ZQN for Queenstown, and WSZ for Westport.

The original airport in Nashville, Tennessee, was built in 1936 as part of the Works Progress Administration and called Berry Field with the designation, BNA.

[7] The code BKK was originally assigned to Bangkok–Don Mueang and was later transferred to Suvarnabhumi Airport, while the former adopted DMK.

The airports of Hamburg (HAM) and Hannover (HAJ) are less than 100 nautical miles (190 km) apart and therefore share the same first and middle letters, indicating that this rule might be followed only in Germany.

These include: Some airports are named for an administrative division or nearby city, rather than the one they are located in: Other airport codes are of obscure origin, and each has its own peculiarities: In Asia, codes that do not correspond with their city's names include Niigata's KIJ, Nanchang's KHN and Pyongyang's FNJ.

EuroAirport Basel Mulhouse Freiburg, which serves three countries, has three airport codes: BSL, MLH, EAP.