Not at all. If you have private land ( say, a garden or a field ) near a display then the 'authorities' can do nothing about prohibiting others from using that land with your permission. Short of going to court for an injunction. After all, I might just happen to have my birthday on the same day as Farnborough's public show and have invited 70 friends around to celebrate...
Accessing such land might require turning-up before road closures are imposed but most enthusiasts won't find that a problem.
And thats exactly why the display area at this years Farnborough has been moved, I think you 70 birthday guests are going to be disappointed itf they think they will get close to the action from your back garden ! As for owning a field, if the authorities decide that standing in your field constitutes a danger to yourself then the airshow well be stopped until you leave your field !