Of course flights have to planned and they should stick to those plans. Airshow displays doubly so as there are strict rules as to what they can and cannot do, and strict rules as to who can fly and what they can fly. The guy flying the hunter was experenced, and according to those that actually knew him, the last person to do something he wasn't approved to do.
The trouble with events like this is that everyone wants an instant answer. They won't get one (it will take months for the AAIB to piece together the real facts) so they like making them up. Witness the lovely article in the Daily Mail quoting an "expert" and "former raf aerobatics instructor" who obvious already knows all the facts because the pilot "has got long hair and wears a cap like that, you get the feeling that he's a glamour puss rather than a professional pilot" and "He broke the rules as far as I'm concerned, flying over anywhere there were people" and "was wrong to be flying below 500ft, had too much fuel on board and 'should have been nowhere near' the A27"
Long hair doesn't makes someone a suicidal show off, there is no evidence yet that he deviated from his approved flight plan (the mail even have another pilot say the manouver "looked exactly the way it should be done") and many aircraft went somewhere near the A27 that day, is you would expect because it is basically off the end the runaway. All approved by the powers that be.
Obviously something went wrong, but how about we find out what that was before damning the pilot as a mass murderer or saying airshows are the spawn of the devil?
Or is that being too boring and sensible?