Some are. RAF Northolt, EGWU, is used by civilian private jets going into the London area. $375+20%VAT to land the King Air there, so not too unreasonable.
Most airports were originally built as RAF stations but are now operated as private companies.
I got interested and started looking into other airports around London. Biggin Hill (EGKB) is another airport used for corporate travel, with 5900' of runway. Landing there is a reasonable $250. Add $79 to fly the ILS on the way in, $167 for handling, $81 for parking for more than 2 hours (this is per day), $24 per passenger, so around $650 in fees for our average visit. Be glad we don't need a GPU for start up at $76 or to fly in with a pet at $304!
London City Airport's charging scheme is too complicated to even begin with, but I note their 'Minimum Invoice' value is $2665. I guess if your fees are less than that it's free.... Right?
Maybe I'm picking airports that are too big... Oxford (EGTK), 50 miles away from London should be pretty cheap with only a 5000' runway. Landing is a bargain, at $184. Handling $142, Parking $61, and $47 for our ILS. Only $434 for the trip!
Strange how many English people come here to fly...
