I have it from the navigator on board that the then OC 101 Sqn (Sqn Ldr Cassidy I think) flew his Canberra B2 under the Clifton Suspension Bridge in C1951!!! Very early one summer morn apparently so not too many witnesses.
Didn't Ray Hannah fly under a bridge on the Tyne for the filming of "Piece of Cake"...
...and the chap in the Hunter flying through Tower Bridge in 1968...
...and a stunt pilot in a tiger moth pretending to be Lady Peneplope in a Thunderbirds film flew under a motorway bridge in the late '60s.