Airport ABCs: An Explanation of Airport Identifier Codes
From ABC (Albacete, Spain) to ZRH (Zurich, Switzerland), airports around the world are universally known by a unique three-letter code: the "International Air Transport Association (IATA) Location Identifier" in aviation-speak. It's obviously much easier for pilots, controllers, flight attendants, travel agents, frequent flyers, computers and baggage handlers to say and write ORD than the O'Hare International Airport in Chicago, Illinois—but how did this practice start, and why are some airport codes easy to understand (ABE and ZRH) while others seem to make absolutely no sense (ORD)?