Global Distribution Systems (GDS) is the major Computer Reservations System (CRS) that book and sell tickets for multiple airlines. Airlines divest (opposite of invest) most of their direct holding to dedicated GDS companies, who make their system accessible to consumer through Internet gateways. GDS allow users to book hotel, rental cars, airlines tickets as well as cruise line.
Computer Reservations 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, CSRes were later extended for the use of travel agents.