HH, Northolt is the nearest to the Royal Free Hospital. Having an Ebola or other haemorrhagic fever patient on transport is risk, should be the shortest possible transfer time.
Ever tried to move a critically ill aeromedical patient, no I suspect not, I have. Biggin Hill is difficult to transfer from in particular with spinal injury patients, Luton is 40 miles away Oxford restricted hours and capability to handle aeromedical flights, Farnborough again distance. All others far too expensive.
Why shouldn't the MoD make money from their airfield?
The owners of Biggin Hill and Kidlington have wanted Northolt closed for a long time and even went to court about it and failed. Is there any form of connection between them and the council?