The conglomerate was founded in 1951 as a merger between the three Scandinavian flag carriers Aerotransport (ABA—Sweden), Det Danske Luftfartselskab (DDL—Denmark), and Det Norske Luftfartselskap (DNL—Norway), after the three had been cooperating on international routes since 1946. Until 2001, the three national companies owned a fixed share of the SAS Group, after which the shares of the three companies were merged. The SAS Group previously owned the Rezidor Hotel Group and Braathens and had a minority interest in bmi, airBaltic, Texas Air, Thai Airways International, and LAN Airlines. SAS was a founder of the Amadeus Computerised Reservation System and the Star Alliance, where several of the group's airlines are members. SAS runs the frequent flyer program EuroBonus.