From A(MS) to Z(RH) – The ABC of Airport Codes

Anyone who books a flight inevitably encounters three letters, the so-called airport codes. For many, the codes are a fascinating aspect of travel, but they can also lead to a guessing game. After all, how do these puzzling combinations come about? Let’s take a look and unravel this alphabet soup. 

Does the sound of a suitcase roll spark wanderlust in you? Maybe even more so when you see the luggage label with the barcode and the three letters of the destination airport dangling on your suitcase? Hidden behind these letters are historical developments, global complexities, as well as amusing curiosities – as well in Switzerland. It is not uncommon for airports to even use the three letters for marketing purposes. 

To avoid confusion when booking flights, a standardized global system is essential. This is ensured by the International Air Transport Association (IATA), which has been assigning airport codes (also known as IATA codes or "three-letter codes") since the 1930s. However, there is no logical standard behind this, which is due to historical development. 

Los Angeles International Airpot (LAX)
Airports often use the three letters for marketing purposes and as large photo subjects, such as here in Los Angeles. © Adobe Stock

How airport codes are made up
The abbreviation often consists of the first three letters of the location (AMS - Amsterdam, FRA - Frankfurt, SIN - Singapore). Since larger cities have several airports, they require separate codes (LHR - London Heathrow, LGW - London Gatwick, LCY - London City). To make things even more complicated, large cities with several airports also have the Metropolitan Area Code. When a passenger searches for LON on a booking platform, flights to all airports in the British capital will be displayed, although LON will never appear on the baggage tag because it is not assigned to a specific airport. 

You've probably noticed airports named after famous people (JFK - John F. Kennedy, New York; CDG - Charles de Gaulle, Paris). Why is Dublin abbreviated to DUB and not Dubai (DXB)? This abbreviation was already in use when the first airplanes landed in the Emirates. New airports must therefore use whichever codes have not yet been used. 

From the weather station to the airport
By looking back further in the history books, you will find that the origin of the codes goes back to the American weather service, which had two-letter codes. With the increase in air traffic, the system was expanded to three letters for the airport to orient itself to a nearby weather station. Usually, the letter X was appended to the weather station code, turning LA into LAX in Los Angeles, for example. 

Because in the USA the initial letters N were originally intended for the Navy and W for radio stations, the code of the capital city airport Washington does not begin with W but is called IAD (Washington International Airport Dulles), or EWR for Newark in New Jersey. There are many such special cases around the globe. However, abbreviations also remain omnipresent witnesses of time. LED for St. Petersburg, for instance, dates back to the time when the city was called Leningrad, and Mumbai (formerly Bombay) still bears the code BOM today. 

Mulhouse, France – August 31, 2019: Terminal of Basel Mulhouse airport (EAP) in France.
EuroAirport Basel-Mulhouse-Freiburg has two abbreviations (BSL and MLH) and is the only airport in the world to be operated by two countries. © Adobe Stock

Special case Switzerland
Among the numerous international special cases, it is not surprising that Switzerland has one as well. EuroAirport Basel, Mulhouse, Freiburg is located in the Switzerland-France-Germany triangle and is the only airport in the world that is operated jointly by two countries (Switzerland and France). Accordingly, it also has two IATA codes: BSL (Basel), MLH (Mulhouse), and until 2021 even a third one, namely EAP (EuroAirport).

By the way, IATA is based in Montréal, Canada (YUL), which brings us to another peculiarity. Most airport codes in Canada begin with the letter Y. However, the reason for this is entirely clear. The theories are almost as varied as the amount of letter combinations, which are limited to exactly 17,576 with three letters. With over 40,000 airports worldwide, this means that these must have a certain volume of traffic in order to obtain one of the coveted "three-letter codes". And how can all the other airports be distinguished? 

Travel stickers. Airport vintage luggage labels. Retro baggage tags mockup. Isolated colorful flight cardboard badges with barcodes. Airline coupons from various cities. Vector airplane tickets set
With three letters, there are exactly 17,576 possible combinations. In addition to the well-known codes, there are also some amusing airport abbreviations. © Adobe Stock

Even more (funny) codes
Pilots and air traffic controllers in particular work with four letters in order for everyone to know exactly where the flight is headed. These four-digit codes, which are assigned by the International Civil Aviation Organization (ICAO), are hardly known to passengers. As a rule, the first letters represent the region: for example L for Southern Europe, S for Switzerland. So the code for Geneva is LSGG and for Zurich LSZH. At least there seems to be a bit of a system behind this. 

Finally, we return to the three letters by putting the codes together in the form of a few amusing combinations. 

LOL, WIL’ TEL’ MOM AND DAD, REA-LLY FUN! OMG, SOO HOT AND WON-DER-FUL, WOW! 

LOL (Derby Field, US), WIL (Wilson, Kenya), TEL (Telupid, Malaysia) MOM (Moudjeria, Mauretanien) AND (Anderson, US) DAD (Da Nang, Vietnam), REA (Reao, Franz. Polynesien) LLY (South Jersey, US) FUN (Funafuti, Tuvalu)! OMG (Omega, Namibia), SOO (Söderhamn, Schweden) HOT (Hot Springs, US) AND (Anderson, US) WON (Wondoola, Australia) DER (Derim, Papua New Guinea) FUL (Fullerton, US), WOW (Willow, US)! 

If you are curious about more exciting background information or would like to bring even more order to the alphabet soup of airport codes, we strongly recommend the video The Maddening Mess of Airport Codes!