Take ear defenders. The crowd line is very close to the aircraft, much closer than you would be allowed to go at a 'proper' airshow. There are also exhibits at brunty you won't see anywhere else. If you've never been I thoroughly recommend it. be aware however that it's pricey. Be prepared to pay £10-15 per adult. Children may be free.
Be wary of getting suckered into volunteering, it is very hard work and you will quickly be taken for granted.
N