Which statement best describes the difference between IATA and ICAO airport codes?

• A. IATA codes are three-letter codes used by airlines and travel; ICAO codes are four-letter codes used by ATC and aviation operations.
• B. IATA codes are numeric; ICAO codes are alphanumeric.
• C. IATA codes are four-letter codes; ICAO codes are three-letter.
• D. IATA codes are used only domestically; ICAO codes are used internationally.

Answer: (A)

Two common airport code systems serve different purposes and audiences. IATA codes are three-letter identifiers used by airlines, travel agents, baggage handling, and passengers for tickets, schedules, and luggage. ICAO codes are four-letter identifiers used by air traffic control, flight planning, and official aviation operations for safety and coordination; these codes are standardized internationally and often include a regional prefix (for example, many U.S. airports begin with K).

An example helps illustrate the difference: Los Angeles International has an IATA code of LAX for passenger-facing uses, and an ICAO code of KLAX for operational procedures. This shows how the same airport can have a short, everyday code for public use and a longer, system-wide code for technical and safety purposes.

So the best description is that one system is three-letter for passenger-facing use, while the other is four-letter for ATC and operations. IATA codes are not numeric and are not four-letter; ICAO codes are not used only domestically and are not three-letter.