Walnut,
There is enough congestion in the air around LHR and LCY as it is, Now its being suggested to hugely increase air traffic in the form of airliners into Northolt with all the extra spacing, and airspace ?
A large amount of passengers using LHR connect with their alliance partners and now its being muted to bus them 7 miles through heavy road traffic from LHR to Northholt after a long flight,... and thats going to be acceptable to business passengers.
Nigel