Police think a firework might have been the cause of a blaze which destroyed two planes worth £1m on Saturday.
The fire started in a canvas aircraft hangar at Southend Airport in Essex.
A rare 50-seat passenger jet and a timber aeroplane were both completely destroyed.
There was a firework party at a club nearby and officers think a stray firework could have landed on the hangar roof.
The crew of another plane which was coming in to land at the airport spotted the fire and alerted the control tower.
Police are now investigating exactly how it started.