Ever wondered why the Calabar Airport is Designated CBQ and Lagos Airport as LOS on your boarding pass? Or why the designation for Vancouver International Airport is YVR? Have you bothered to know the story behind the queer SUX abbreviation for Sioux City, Iowa or why Beijing is given the code PEK?

Have you ever stopped to wonder where those unique three-letter airport codes came from? If you have not, then here is your crash course. Airport codes or Location Identifier Codes are an enigma as we see them constantly but only know what few of them mean. For starters, the three-letter airport codes came about because pilots found the National Weather System’s two-letter codes inadequate to identify all the available airports.

Today, airport codes are called International Air Transport Association Airport Codes (IATA) and are established by the airline trade association, founded in the 1940s. Thus, an IATA airport code, also known an IATA location identifiers are the three-letter codes designating many airports around the world, defined by 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 codes are an integral part of the travel industry, and essential for the identification of an airline, its destinations and its traffic documents. They are also fundamental to the smooth running of hundreds of electronic applications which have been built around these coding systems for passenger and cargo traffic purposes. You might know that ATL stands for Atlanta, but can you identify the cities for PEK, BOM, BDL, MSY, and SNA? If you’re curious, they’re the codes for airports in Beijing in China, Mumbai in India and Hartford, Connecticut; New Orleans, Louisiana, Orange County, California all in America. Most of these words are keys or hints the airport’s or city’s history.

The Canadian airports are especially quite intriguing because many of their codes don’t seem to have any correlation with the cities where they are located. Now here’s an easy way to find out what airport codes actually mean. The highlights are the codes that don’t match up with their cities.

EWR (Newark): Newark is called EWR because the Navy reserved all the codes that begin with “N.” PDX (Portland): Why do some airport codes have an X at the end? Portland’s is an illustrative case: when airport codes switched from two to three letters in the 1930s, some cities that already had airport codes added an X to the end as a quick fix. Portland started as PD, and then added X. Some, like San Francisco’s airport, added other letters (which is why its code is SFO).

YVR (Vancouver): Canadian airport codes start with a “Y”, which is why Vancouver has one before the more predictable VR.

PEK (Beijing): Sometimes airport codes are historical artifacts. PEK refers to Peking, an older, English name used for Beijing gotten from the postal map romanization of Mandarin Chinese.

BOM (Mumbai): The airport code is BOM, a reference to its former name of Bombay, derived from the Isle of Bombay, one of the seven islands that made up the archipelago on which it was once built.

CBQ (Calabar): Designation ordinarily would have been CB for the Magaret Ekpo International airport, but when airport codes switched from 2 to 3 characters, it was imperative that newly built airports added a third alphabet....

Read more at: http://www.intercityadventures.com/ever-wondered-about-airport-codes/