Low flying at airshows brings out the gasps from spectators. Have look at this screen grab from an 8-mm film I shot at one of the Biggin Hill Battle of Britain displays in the 1960's. I estimate aircraft was around 20ft above the crowd and inverted.
Identification of the aircraft type and at which year's BoB I took the film would be welcome.
Approaching
Passing
Departing
Climbing away - still inverted
Very Late PS. It was Neil Williams