Scandinavian Airlines System (SAS) is a multi-national airline for Denmark, Norway and Sweden, and the leading carrier in the Scandinavian countries, based in Stockholm, Sweden and owned by SAS AB. It is a founding member of the Star Alliance. It is also the founder of Air Greenland, airBaltic, Linjeflyg, Spanair, Thai Airways International, and the former charter airline Scanair, and is the 20% owner of bmi as well as 49% of Estonian Air. SAS operates out of three primary hubs, Copenhagen-Kastrup Airport, Stockholm-Arlanda Airport, and Oslo-Gardermoen Airport. In 2006 Scandinavian Airlines had 25 million passengers and the SAS Group had 38.6 million passengers.