A computer reservations system (or central reservation system)(CRS) is a computerized system used to store and retrieve information and conduct transactions related to air travel.Originally designed and operated by airlines, CRSes were later extended for the use of travel agencies.Major CRS operations that book and sell tickets for multiple airlines are known as global distribution systems (GDS).
Example: Airlines have divested most of their direct holdings to dedicated GDS companies, who make their systems acceible to consumers through Internet gateways.Modern GDSes typically allow users to book hotel rooms and rental cars as well as airline tickets.They also provide acce to railway reservations and bus reservations in some markets although these are not always integrated with the main system.
