I cannot see what relevance accident statistics on UK roads have to do with accident statistics at privately hosted air displays. A better comparison would be between air displays and F1 racing.
My late father, a QFI rated 'exceptional', between operational tours flew in RAF air displays in the late 1940's and was a University Air Squadron instructor in the early 1950's, at a time when these Squadrons competed in Air displays.
There is an important difference between RAF pilots and students performing aerobatics as part of their training and retired RAF pilots engaging in aerobatics at public events, the sole intention of which is to entertain.