A German aviation watchdog is scrutinising a fly-past by Air Berlin and amp;#39;s last long-haul flight to its hub in Duesseldorf, which German media said was the pilot and amp;#39;s unique way of saying goodbye to his passengers and the insolvent airline.The pilot of the flight from Miami on Oct. 16 pulled up the aircraft above the runway in Duesseldorf and made a low pass over the airport before coming around and landing.