Which code is four-letter and primarily used for air traffic control and flight operations?

• A. IATA code
• B. ICAO code
• C. FAA code
• D. AOC code

Answer: (B)

ICAO codes are four-letter airport identifiers used in air traffic control and flight operations. They’re standardized by the International Civil Aviation Organization so controllers and pilots around the world can uniquely identify each airport in flight plans, routing, and communications. The four-letter format also allows regional prefixes, so the code clearly points to the country or region and the specific airport, which is essential for international flight coordination. In contrast, IATA codes are three-letter and used mainly for passenger services like tickets and baggage handling, not for ATC. FAA identifiers are a national system used within the United States, and AOC refers to an Air Operator Certificate, not an airport code. So the four-letter ICAO code is the one designed for ATC and flight operations.