I suspect in another 15 or 20 years many of those "airports" listed will be housing estates, and those that aren't will still be waiting for the promised squadrons of LHR shuttles to arrive.
Expressed much better than I could Logohu. Didn't spot BHX, MAN, STN, LTN. EMA, or EDI in that list. Are they not in the Bicycle Association or Bus Authority?