Air Berlin, branded as airberlin or airberlin.com was a major German airline. At its peak, it was Germany's second-largest airline, after Lufthansa, and Europe's tenth-largest airline in terms of passengers carried. It was headquartered in Berlin and had hubs at Berlin Tegel Airport and Düsseldorf Airport. At the time of its insolvency, it was a member of the Oneworld airline alliance, having joined in 2012.