You see them everywhere, when booking your flights, on your boarding pass, on your luggage tag, whether you notice it or not, there is always a three-letter code accompanying the full name of an airport. Most of them make sense, BRU for Brussels Airport, JFK for New York’s John F Kennedy Airport. But why is Chicago O’Hare Airport’s code ORD or why is there an X in Dubai’s DXB?
1. History of airport codes
As air travel became more popular and the aviation industry developed, airports needed a simple system to be classified. Codes first started being used in the 1930’s. These were only two letters and the airports themselves chose them, usually based on the name of the city they were located in.
By the late 1940’s however, there were more airports than two-letter combinations, so the three letter codes were adopted. Then in the 1960’s, the International Air Transport Association (IATA) stepped in to document and standardise the codes internationally. For those that only had two letters, it was easier to just add an X than chose another code completely, thus Los Angeles International Airport’s LA became LAX and Dubai’s DB became DXB.
2. IATA
IATA‘s Airline Coding Directory (ACD) and Location Identifiers are now the official industry source for airline and location codes worldwide. These are used as a single point of reference for reservations, schedules, timetables, telecommunications, ticketing, cargo documentation, legal, tariffs and other commercial/traffic purposes. Besides airports, location identifiers are also assigned to bus stations, rail stations and ferry ports that are involved in intermodal airline travel.
3. ICAO
IATA codes are the ones known by passengers, however, the International Civil Aviation Organization (ICAO) assigns four letter codes which are the international standard for interoperability between air navigation service providers. Pilots, dispatchers and air traffic controllers work with ICAO codes rather than IATA ones.
While IATA’s codes are based either on the name of the city or of the airport, ICAO codes are based on geographic region. The first one or two letters designate the region and/or country, while authorities in each country then delegate the remaining available letters in the code.
For example, the letter of the northern region of Europe is E, so all the codes for airports in these countries start with E. Then, the letter for the UK is G, thus the ICAO code for London’s Heathrow Airport is EGLL or, for Liverpool John Lennon Airport, EGGP. The US only has K, so airports are then assigned three letters, for example, Florida’s Fort Lauderdale-Hollywood International Airport is KFLL.
4. Oddities
Sometimes the codes don’t seem to make sense. One explanation for this is that the airprots changed names at some point, but the original codes were kept, for example Chicago O’Hare Airport is ORD because it was called Orchard Field Airport before 1949.
In other cases, the three-letter combination gains a different meaning when read as a word. Brazil’s Poco de Caldas Airport’s code is POO, while Russia’s Bolshoye Savino Airport is PEE. Iowa’s Sioux City is SUX, but the airport decided to make the most of a funny situation and sells “Fly SUX” souvenirs in the gift shop.
Others are just amusing coincidences, like Nevada’s Derby Field Airport, coded LOL, Namibia’s Omega Airport – OMG or Arizona’s Yuma Airport – YUM.
