IATA vs ICAO codes
IATA and ICAO codes both identify airports and airlines, but for different audiences. IATA codes are shorter, 3 letters for airports and 2 characters for airlines, used for tickets and baggage. ICAO codes are longer, 4 letters and 3 letters, used by pilots and air traffic control.
The short version
| IATA | ICAO | |
|---|---|---|
| Airport code length | 3 letters (JFK) | 4 letters (KJFK) |
| Airline code length | 2 characters (AA) | 3 letters (AAL) |
| Who uses it | Passengers, booking, baggage | Pilots, ATC, flight plans |
| Geographic pattern | No | Yes, by first letter |
| Codes reused over time | Sometimes | Rarely |
Airports: JFK vs KJFK
Take John F. Kennedy International Airport. Its IATA code is JFK, the code on your ticket. Its ICAO code is KJFK. The leading K tells you it is in the contiguous United States, because ICAO codes are regional: the first letter marks a broad zone of the world. IATA codes carry no such pattern.
Want to see both for a specific airport? Every airport page lists them together, for example JFK, LHR and HND.
Airlines: two letters vs three
Airlines have a two-character IATA code and a three-letter ICAO code. The IATA code is the flight-number prefix you book under; the ICAO code is what controllers use, and it maps to the airline's radio callsign. Compare them on any airline page.
Why both systems exist
IATA optimises for humans buying tickets: short, memorable, and only three letters so they fit on a bag tag. ICAO optimises for a global operational network: unique, regional and unlikely to be confused over a crackly radio. Neither replaces the other, which is why almost every airport carries both.
Frequently asked questions
What is the difference between IATA and ICAO codes?
IATA codes are shorter and used for passenger-facing tasks like tickets and baggage. Airport IATA codes are 3 letters, airline codes 2 characters. ICAO codes are longer and used operationally by pilots and air traffic control: 4 letters for airports, 3 for airlines.
Why does JFK have two codes?
JFK is the IATA code used for booking and baggage at John F. Kennedy International Airport. KJFK is its ICAO code, used in flight plans and by air traffic control. They identify the same airport for different audiences.
Are ICAO codes geographic?
Yes. ICAO airport codes follow a regional pattern. The first letter marks a broad region, for example K for the contiguous United States, E for northern Europe and Y for Australia, so codes cluster geographically.
Which code should I use?
If you are booking travel or reading a departure board, use the IATA code. If you are filing a flight plan or working in aviation operations, use the ICAO code.
New to the topic? Start with what is an IATA code.