KATHY SHUPE: My name is Kathy Shupe, and I'm from Tucson, Arizona. And I want to ask</s>CNN: How are city airport codes determined in the United States and in Canada?</s>MIKE WASCON, V.P. COMMUNICATIONS, AIR TRANSPORT ASSOCIATION: The Federal Aviation Administration here in the United States, working in conjunction with the Department of the Navy and Transport Canada, the Department of Transportation equivalent in Canada, set the three letter codes for airports. For example, when Detroit's city airport was built, the code was simply DET, short for Detroit. When metropolitan Wayne County Airport was built, the code was DTW for Detroit, Wayne County. Most of these codes are permanent and very rarely is a code change. The most prominent change occurred in the New York City area when Idlewild Airport, formerly IDL, was changed to John F. Kennedy Airport and the new designation of JFK.
ASK CNN: How are city airport codes determined?