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Glossary for the airline industry

From A-Z, this glossary covers definitions and explanations for common airline industry terminology.

voluntary cancellation

A cancellation of a ticketed itinerary that the passenger requested where there is no replacement itinerary and the ticket is refunded or discarded (no value). Does not include lost tickets.

voluntary changes

A change in the ticketed itinerary that the passenger requested where there is a replacement itinerary and the ticket is reissued/revalidated. Passengers who wish to standby for a flight are not included in this definition.


List established when there are no more readily available spaces; names awaiting seat availability.


Any weakening or elimination of rules conditions as part of a private fare sale.


Extensible Markup Language. A set of rules for encoding documents in machine-readable form.

XML messaging

The use of data coded in XML to communicate between two devices.


A profitability indicator that is calculated by subtracting CASK from RASK.

yield management

The practice of changing availability of seats for each booking code on a flight. This process ensures optimized revenue per seat sold and entails using detailed historical booking, fare, and profit information, with powerful algorithms for implementation. Many airlines use what is called O&D revenue optimization, which creates yield management models across a carrier's entire network, rather than on specific flights only. ATPCO's RBD data provides the link between inventory and price, and is used in these systems.


See Carrier-Imposed Fees.


A generic carrier code used for carriers that participate in the IATA agreements. Any participant may use the fares and rules identified by carrier YY.


Zonal Employee Discount.

zonal fare

A fare where the origin, the destination, or both are expressed as a user-defined zone.


Divisions of geographic areas of the world. ATPCO Zone codes are three numbers that begin with 0 or 1 for Area 1; with 2 for Area 2, and with 3 for Area 3.