Lukeafb1 and Wycombe,
Greenham a major airport? I think not. Look at a map. Off one end of the main runway you have Newbury, off the other end you have the Atomic Weapons Research Establishment, and the whole place is built on a quite delightful common. It would be a ghastly place to have any kind of airport.
As far as the AWRE goes, I do recall in the early to mid seventies when they were considering holding a jet aerobatic competition there the rush from Eastern European teams to enter was a tad embarrassing!