In the context of multi-leg flights, the validating carrier (a.k.a. issuing carrier) is the airline that validates or issues tickets, and the one that receives the money when the flights are booked. In the event of cancellations this is the carrier with which the flyer has credit. However, with the advent of online booking, passengers are usually unaware of who their validating carrier is. The only way to tell who the validating carrier is for a passenger to check the first three digits of his/her ticket number after booking the ticket. Airlines who are members of ARC or IATA BSP have their own prefix for airline tickets.
Examples of prefixes of several major airlines include:
Asia Pacific Airline PrefixAir China 999SriLankan Airlines 603All Nippon Airways 205IndiGo 312Qantas 098Singapore Airlines 618
Europe Airline PrefixAir France 057British Airways 125Lufthansa 220Ryanair N/AAir France 057Turkish Airlines 235Scandinavian Airline System SAS 117Finn Air 105LOT Polish Airlines 080KLM Royal Dutch Airlines 074Hahn Air 169ITA Airways (ex Alitalia) 055Iberia 060TAP Air Portugal 047Aegean Airlines 390Virgin Atlantic932
North America Airline PrefixAmerican Airlines 001Air Canada 014Delta Air Lines 006Southwest Airlines 526United Airlines 016
Near East Airline PrefixEl Al 114