When I went to Le Bourget, the maximum I had was 300mm, so yes it is adequate, but only barely. My current 400mm would have been very welcome at Le Bourget.
The price of being back in the VIP boxes is that you are a little further away. On the other hand, you won't have to wear a neck brace after straining your neck trying to take pictures straight up
I'd consider begging, borrowing, or stealing a 1.4x or 2.0x converter for the airshow, and compensate for the loss of light by using a really good high speed slide film, of which there is only one in existance: Provia 400F. Yes, it's expensive, but how often do you go to Farnborough?
For the static display, normal film and wide angle lenses are the things to have.
The only thing you should feel when shooting a terrorist: Recoil.