Following an 11 November debate in the UK Parliament on the proposal to add a third runway to relieve congestion at London Heathrow, the project is looking less secure.
After recent declarations by London mayor Boris Johnson and the Conservative party that they are opposed to the additional runway, the parliamentary debate demonstrated that determined opposition to the policy, previously considered a certainty for Government approval, has become more organised.
The Conservative party, at present still leading the Labour Government in polls about which way electors would vote at a general election, has said it would reverse any approval for the third runway if it were elected.
UK prime minister Gordon Brown told Parliament that the decision, to be announced next month, would be taken following "full consideration" of the expanded airport's ability to meet Europe's environmental standards.
But about 50 Labour members of Parliament have signed a parliamentary motion calling for "alternatives" to the third runway to be considered.
The UK's Royal Aeronautical Society also hosted an open debate, on the same day as Parliament's, about whether the need for additional runway capacity in the southeast UK should be met by expanding Heathrow or by building an all-new, four-runway offshore airport in the estuary of the river Thames.
Four speakers addressed the issue from various viewpoints. Those arguing for a Thames airport did so passionately, on the grounds that the issue had been ducked following three separate studies since the 1970s when the concept was originally proposed, and claimed that now was the time to act in a visionary manner to create what would be a modern, 24-hour airport.
Speakers arguing against it claimed that, by being coastal, the airport would be a geographical cul-de-sac with no natural catchment area or industrial support, and would require sweeping infrastructural development - including surface transport systems and the creation of a completely new community for airport workers.
The lowest Government estimate of the cost was £12 billion ($18 billion), according to London School of Economics professor of economic history Tim Leunig, who said it would be "an airport in the middle of nowhere".
Conservative member of parliament for the cities of London and Westminster Mark Field, who argued against the third Heathrow runway, was among those who said that, although theoretically it was the most cost-efficient solution to lack of capacity, the runway was just an exercise in "papering over Heathrow's cracks" and would quickly become saturated.
Heathrow operator BAA's strategy and regulation director, Mike Forster, argued that, despite its capacity problems, the airport was - at present - the world's favourite hub.