What the government and major british airlines have failed to recognise is the need for a northern hub for international flights to take some pressure away from the SE. Because of BA and Virgin's tunnel vision for the SE they are currently losing valuable revenue regionallyto EK eastbound and CO westbound.
I would seriously suggest Newcastle for the northern hub for the following reasons -
Equidistant between all of the northern towns within a 150 mile radius and Edinburgh / Glasgow.
Regular air links to Belfast, Aberdeen and Bristol, Birmingham and Cardiff (if they want to avoid LHR/LGW and the hassle involved).
Excellent rail links to all northern towns with a spur from the East Coast mainline being on the NCL masterplan
Plenty of room for expansion runway wise, terminal buildings, stands, car parking etc.
Plenty of holding space over the nearby north sea (if required).
EK have proved the value of regional links with a second daily flight due from NCL in 12 months - who would have believed one flight would be viable? - don't underestimate the regions !
Obviously a lot of investment would be required, but probably only a fraction of that spent in the SE.
As BA quoted 34% of passengers come from outside SE, then why not fly these from the north. I personally do not see where BA's future revenue growth will come from with LHR full and LGW almost full. Open Skies is typical of them when they can't see where their own market is.
This could also be another small step to bridge the north - south divide, but I'm not holding my breath.