Air accident investigators are looking into safety procedures at air shows across the UK after an old plane crashed in West Sussex.
The planes involved aren't used anymore except in air displays and don't carry passengers.
It was a very rare event that shocked people watching.
The pilot - who's very experienced - was trying to do a loop-the-loop. But the aircraft he was flying was too low and couldn't recover.
The pilot survived but is now being treated in hospital.
But sadly the plane did land on a busy road and it's thought 11 people have lost their lives.
Watch Leah's report to find out more.