Every commercial airport on planet Earth possesses two distinct identifying codes: a 3-letter IATA Code and a 4-letter ICAO Code. While they often designate the exact same strip of concrete, they were engineered by different international organizations for fundamentally different missions.
1. IATA Airport Codes (3 Letters)
The International Air Transport Association (IATA) represents the commercial interests of world airlines. IATA codes are three-letter alphanumeric abbreviations engineered for passenger convenience, ticketing systems, baggage tag routing, and public departure screens:
JFK— New York John F. KennedyLHR— London HeathrowDXB— Dubai InternationalCMN— Casablanca Mohammed V
Because there are only 17,576 possible combinations of three letters ((26^3)), IATA codes are finite and often shared or recycled when airports close.
2. ICAO Airport Codes (4 Letters)
The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations responsible for international civil aviation safety, navigation, and regulatory standardization. ICAO codes consist of 4 letters and are strictly structured according to regional geography:
- First letter: Global region or continent (e.g.,
K= Contiguous United States,E= Northern Europe,L= Southern Europe & Mediterranean,G= Northwest Africa,O= Middle East,R= East Asia). - Second letter: Country or national airspace sub-region.
- Third & Fourth letters: Specific aerodrome station identifier.
For example, EGLL identifies: E (Northern Europe) → G (Great Britain) → LL (London Heathrow). ICAO codes are used exclusively by pilots, air traffic control towers, flight plan dispatchers, and aviation weather reports (METARs/TAFs).