ICAO Airport Code

Definition

A four-letter code assigned by the International Civil Aviation Organization to identify airports and air navigation facilities worldwide. The first letter generally indicates the region (Z for China, E for northern Europe, K for the contiguous US). ICAO codes are used by air traffic control, flight planning systems, and meteorological services. Examples: ZSPD (Shanghai Pudong), EDDF (Frankfurt), KLAX (Los Angeles). While IATA codes (3 letters) are more visible to passengers and shippers, ICAO codes are the official identifiers in aviation operations.