A CAA economic cost/benefit study in the 1970's concluded that the only economically viable scenario for airport provision for people living in the South-West region of England (much bigger than you might think, it pretty much includes Dorset, Wiltshire and Gloucestershire as well as Avon, Somerset, Devon & Cornwall) would be to close ALL existing airports in the region so that traffic would be directed to Heathrow and/or Birmingham.
As a statement of economic fact this conclusion was quite correct. The net cost per passenger journey between home and aircraft was minimised in this arrangement, by substituting longer road/rail journeys for local airports.
It never happened, of course, as owners became more entrepreneurial and drove traffic to their airports; Bristol started it, followed by Exeter when BAA took over (although EXT growth ceased for some years after they were kicked out by the Council worthies).
By concentrating aircraft at very few airports the average costs per ATM are reduced by large amounts, of course.
But as access costs grow, with air pollution becoming a much more significant factor than it used to be both for airports and for access routes to them, and an exponential and unforeseen growth in the number of surface journeys for all reasons in the UK the whole equation looks very different. This is especially true in the South-East; perhaps the most important reason for NOT having a 3rd LHR runway is that the air pollution increase from surface traffic as well as aircraft would be added to an already excessive - and illegal - amount.
People who predict the demise of small airports perhaps forget that, as they also perhaps miss the way that hub-based routes are giving way to regional point-to-point routes using small relatively economic aircraft such as the A320 family, and fast, efficient turboprops.
The most likely reason for demise of a UK regional airport in the next 10 years is probably going to be its own bad management and lack of air transport marketing and development skills. There are several where that outcome is grimly predictable. For some owners the urge to realise industrial or housing land values, rather than run an airport at little or no profit, might prove overwhelming.
Last edited by Capot; 8th Oct 2014 at 16:12.