A German aviation watchdog is scrutinising a fly-past by Air Berlin's last long-haul flight to its hub in Dusseldorf.
German media said it was the pilot's unique way of saying "goodbye" to his passengers and the insolvent airline.
The pilot of the flight from Miami on Monday pulled up the aircraft above the runway in Dusseldorf and made a low pass over the airport before coming around and landing.
On Tuesday, a spokesman for Air Berlin said the Federal Aviation Office was investigating, but declined to provide further details or confirm reports that said the maneuver was an intentional "lap of honour".
Germany's aviation authority said while go-around maneuvres were a normal procedure in air traffic, it had asked Air Berlin for details of Monday's incident involving the A330 plane because it differed from ordinary go-arounds.
