Some two-letter airline codes include AA for American Airlines, AV for Avianca, DL for Delta and MH for Malaysia Airlines. Other codes that are only two letters long include NK for Spirit and VS for Virgin Atlantic.
The International Air Transport Association assigns two-character codes to every airline in the world. These codes are used in reservations, timetables and tickets. Some codes are an acronym of the airline's name, such as AA. Other codes that follow this pattern include AF for Air France, BA for British Airways and UA for United Airlines. Some airline codes are simply the first two letters of the airline's name, such as AV. Other examples of this pattern include CO for Continental Airlines, HA for Hawaiian Airlines and TA for Taca.
Some airline codes use letters from airline names more liberally, as in the case of DL. Other examples of this type of code include JM for Air Jamaica, MX for Mexicana and TK for Turkish Airlines. Some airline codes only use one of the letters in an airline's name, as in the case of MH and VS. Other codes that follow this pattern include EK for Emirates, QF for Qantas and WN for Southwest. In rare cases, such as Spirit's NK, codes may not use any of the letters found in the airline's name.