Martyn, check out the link below for ticket prices, and guys do you know we are leaving at
5am 
stopping for brekkie on the way maybe
Gates open at 7.30am and that is the best time to get there, if not, picture this senario, 3 entrances, off narrow country lanes with about 50,000 people trying to get in
speaking from experience
http://www.airtattoo.com/airshow/Airshow_Tickets