It consists of the charge for a passenger to fly from an origin to a destination and includes the conditions, rules, and restrictions for travelling on the airfare.
Airlines have sold airfares in this way since the beginning of commercial air travel and before computer reservations systems existed.
As new computerized systems were gradually introduced to the air transport industry in the 1960s, this method of defining airfares and managing them within fare codes was further developed, and usage became widespread.
Fare classes are used by most airline reservations systems and revenue management departments to divide every seat on a plane into different categories, each with its own price and set of rules.
More than 450 airlines publish in excess of more than 100 million airfares through the airline-owned airfare database Airline Tariff Publishing Company (ATPCO) for onward distribution to Global Distribution Systems (GDSs) and third-party retailers.
Agents cannot sell some codes, and those seats may be reserved for international connections, loyalty programs, or airline staff relocation.