Airport abbreviations include LAX (Los Angeles, California), CVG (Cincinnati, Ohio), ORD (Chicago, Illinois), YYZ (Toronto, Canada) and DAY (Dayton, Ohio). Other airport codes include JFK (New York, New York) and ATL (Atlanta, Georgia).
Three-letter airport codes are used by airports all around the world. In aviation parlance, they are known as International Air Transport Association Location Identifier. Airport codes originally consisted of a two-letter weather station identification system that was first created by National Weather Service. As the airline industry grew, locations that did not have weather station codes needed a identification system. The three-letter system ensured there were enough codes.