Unsourced material may be challenged and removed. (September 2010). 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, hotels, car rental, or activities.Originally designed and operated by airlines, CRSes were later extended for the use of travel agencies.heir idea of an automated airline reservation system (ARS) resulted in a 1959 venture known as the Semi-Automatic Business Research Environment (SABRE), launched the following year. By the time the network was completed in December 1964, it was the largest civil data processing system in the world.