http://www.waddingtonairshow.co.uk/travel.asp?cpID=15

I presume that you are coming from the south? If you take the A607 then you could find yourself syphoned off to the White Lane/Tower Lane (see map) entrance. This route takes you over the runway. The same goes for the A15 route. It all depends on the traffic at the time as to which entrance that you are directed to. If you are not directed off to White Lane/Tower Lane from the A607 then you will enter the base from the main entrance. If you are on the A15, and don’t get directed off to Tower Lane, then you will enter the base at the crash gate up near to the Waddington Aircraft Viewing Area (WAVE).