A very interesting question.
BA reckon up to 60% of their longhaul traffic is interlining through Heathrow but a breakdown on which is UK and which is overseas generated is harder to come by. I have seen figures that show on some BA longhauls ex LHR 45% of traffic is non UK and it was on this that they based their various "World Airline" ideas.
I heard some figures on the radio the other day which were obviously erroneous, that 30 years ago there were 25 million UK passengers using British airports and that has increased to 150 million today. That would mean every man, woman and child in the UK would be making 2.586 flights per year but I'm not sure how you tell the number of UK based passengers. I use UK airports, have a British passport but live in Ireland and am accepted as "UK" - and domestic passengers are not checked for nationality anyway.
Without compiling the stats for each UK airport operating air transport flights (as opposed to general aviation) I can't give a true figure of overall use, but it is true that there has been an enormous growth in the use of air transport through
the British Isles.
Boeing are correct about the current demand for more direct services - and that goes for everywhere.. That is why we have Continental 757s roaming Europe and the threat (
) of their 737s as well.
The great draw of London, Frankfurt and, once upon a time, JFK was they were all major gateways to their hinterlands as well as being major cities in their own right. The airlines capitalised on this and used these cities as major connecting points when airlines like, for instance, Gulf Air or Singapore or Egyptair didn't fly to the USA, or US Air (in its Allegheny guise) or Piedmont didn't fly to Europe. Airlines are like sheep. If they see a successful use of an airport they will look to serve it if there is a chance they can be as successful. The instances of this are legion.
Heathrow, particulaly, benefitted because in the 1950s it was about as far east as you could go without refuelling, it had the old "Empire" links and provided connections eastward and was on the edge of Europe. Singapore has a similar position in the Far East today.
In addition Britain still liked to play the super power game and it had a base of industry that attracted major business travel and an educational base which attracted worldwide travel, both in and out.
The many cities served from these gateway airports were provided with good connections, increased traffic and the eventual increased desire to, at first transfer to a flight to as near to home as possible, later for direct flights.
In theory, therefore, the end of this should be the growth of direct routes to "provincial" airports to the eventual detriment of the gateway.
To some extent this has happened in the US. In the UK Heathrow has been protected by Governments manipulating route applications whilst, in Germany, Munich and Dusseldorf have built a number of direct long haul routes and a mass of inter European routes.
But, as I have written many times before, this will rapidly become unsustainable and a retrenchment will come sooner rather than later.
Much larger aircraft, running a less frequent schedule will ply the major routes.
In Europe rail will regain some of, not only, its dominance, but its real attraction for business travellers by offering fast city centre to city centre times.
It would require massive infrastructure development to do the same in the USA - akin to the building of the Interstates, but who's to say what will happen when people finally accept what they already know - the chips are nearly down.
Boeing will build then what it can to make money, as will Airbus. Bombardier were building trains before they bought Canadair and De Havilland Canada.
So to sum up, Government interference apart, there will be some loss from Heathrow in the coming years as both European and UK "provincial" airports develop more long and medium haul links of their own.
But all the reports out of EUROCONTROL and, despite the efforts of EATCHIP (European ATC Harmonisation Implementation Project) and other bodies to maximise airspace use, airspace will become more crowded and rationing will militate for superhubs once again