LNDON, England - Over a third (34%) of tourism chiefs believe expanding Heathrow is the best way of solving the UK's airport capacity problems, according to a poll.
Of the 1,300 bosses surveyed, 20% backed the Thames Estuary airport plan favoured by London Mayor Boris Johnson.
It was carried out by the organisers of the World Travel Market event which opens in London on Monday.
The poll comes as Sir Howard Davies begins his government-commissioned work into the UK's airport needs.
The former Financial Services Authority's chief report is due in summer 2015.
World Travel Market director Simon Press said: "It is clear that senior travel executives from around the globe are in favour of expanding the UK's primary airport with a third runway at Heathrow.
"Expanding other airports in south-east England is more popular than building a new airport which suggests that our overseas colleagues think the UK Government should steer clear from an ambitious if expensive solution when there are better options available."
On Saturday, Prime Minster David Cameron said Mr Johnson was wrong to dismiss a third runway at Heathrow and he will not be given a veto on the issue.
Mr Cameron's comments come a day after the mayor criticised a commission set up to investigate airport capacity in the UK as too slow.
Mr Cameron told The Times: "In the end the decision is a national decision that the government has to lead."
It was "not right" he only wanted his preferred options considered, he added.
But Mr Johnson, who opposes expansion of Heathrow, said he felt the decision-making process was too slow and represented a "policy of utter inertia".
He said the inquiry should not even be considering another runway at Heathrow because the idea was "a complete disaster" and "simply will not happen".
The government has so far resisted pressure to build a third runway at the London airport - but many businesses have been lobbying for its expansion.