IATA airport code
The IATA airport code is a three-letter alphanumeric code designating each airport around the world. These codes are defined by the IATA organization of travel agents. The codes are not quite unique: 323 of these approximately 20,000 codes are used by more than one airport. The characters prominently displayed on baggage tags attached at airport check-in desks are an example of a way these codes are used.
While the IATA codes are the most familiar airport codes, the 4-letter ICAO airport codes are also common.
A list of airports, sorted by IATA code, is available. Also, a List of Rail Stations codeshared in agreements between airlines and rail lines such as Amtrak, SNCF French Rail, Deutsche Bahn, Thalys International, and Swiss Rail is available.