Thanks Keesje , one additional point for the non-believers, is the huge money all these companies are investing in participating to those airshows, being Farnborough or le Bourget, If it was not worth their while they would not come back year after year.
and an off-Thread if the mods agree:,
the photo you posted from 1921 shows how advanced some people were 100 years ago, this prototype on the front looks a bit like Virgin Galactic Space 2 craft no ?..