The agenda of those lobbies go directly against the welfare of 1m people living under the flight path and does not consider the indirect costs at any point:
Heathrow itself was built on farmland using war-time regulation to avoid a public enquiry and is badly located: it's to my knowledge one of the only European airports to be built on the West side and at short distance of a capital or major city. Given the winds in Europe are dominantly Westerly or Easterly this is quite a poor planning decision. It explains the huge environmental impact of Heathrow and why over 1m Londoners live directly under the flight path. In this respect, Gatwick, Stansted or Luton are much more sensibly located and are closer to main communications link.
Read this for more on how the South East Regional Air Study neglected indirect costs. In tax only, the negative balance is £8.5 billions in favour of the air travel lobbies… Little has been done to quantify the direct and indirect impact of aircraft noise and pollution.
In conclusion, the massive subsidy enjoyed by air travel and on the other side the equally large but little researched induced costs is based on flimsy economic assumption. If only a small part of those direct and indirect costs and if tax subsidies were removed, Heathrow could DOWNSIZE!
Links: HACAN ClearSkies