There was a debate about this on Radio 4 the other day. In the time honoured fashion they put a greenie (nothing should be built anywhere, ever) against somebody I think from BAA (we should be able to build runways everywhere, and only heavy metal should be allowed to use them), with the inevitable argument.
Then, they hauled in from some UK university a chap who was a "Professor of Sustainable Aviation". He told them both, very politely that they were talking complete airbollox, and explained how you need a certain amount of additional runway capacity, a constant improvement in noise and efficiency, and only build on a handful of occasional nature reserves if absolutely necessary to the economy. Apart from spoiling a good argument, he sounded thoroughly good value for money - anybody know who he was and whether he can be persuaded to join Pprune.
G