Robin
I argued the case for Greenham Common many years ago on another forum. It is ideally located for where business people live, work and want to fly from. And of course it is people paying to sit in the front end which is attractive to the airlines.
This is why Manston/Boris Island is a non-starter unless you want everybody and their businesses to vacate the M4 corridor and up sticks and move to Kent.
Trouble is, like everywhere else that is proposed, the local MPs are cr*pping themselves about loss of their seat if they are seen to support it coming to their area.