The IATA (International Air Transport Association) and ARC (Airlines Reporting Corporation) Number are both unique identifiers for the travel and tourism industry. The IATA number is a unique code that identifies a particular airline. The IATA number is used by travel agents and airlines to book flights, track payments and for other administrative tasks. The ARC number is used by travel agents to identify their agency and to process payments for airline tickets. It is also used by airlines to track ticket sales and to provide credit to the travel agency.