A hot political question in London in recent weeks has been the need for more airport capacity to meet the needs of business in the 21st century. A neutral observer might think that this is essentially a matter that should be settled on the basis of supply and demand and the relationship between these two factors and the costs, which must take into account noise and pollution.

In London, however, the problem has become more of a political than an economic one.

The Conservatives and the Liberal Democrats, who form the present coalition government in Britain, came to power with commitments to oppose the construction of a third runway at Heathrow, London's principal airport. The Labour opposition, which had favored the idea of expansion at Heathrow when they were in power, have also turned against the proposal. One might think that as all three parties are opposed that should be the end of the story.