Aviation companies today branded the Conservatives' opposition to new airport runways "baffling".
The Tories have made it clear that they would not support an extra, third, runway at Heathrow and they are also against a second runway at Stansted airport in Essex.
Ian Godden, chief executive of the Society of British Aerospace Companies (SBAC) said today: "It is baffling that the Conservatives would wish to restrict the growth of airports in the UK.
"Historically they have been a party that supports business and also claims to support economic growth, so their policy to restrict airport capacity is very concerning."
At the Conservative Party annual conference last month shadow transport secretary Theresa Villiers said the Tories preferred new high-speed rail links to expansion at Heathrow.
Since then she has also made it clear that a Conservative government would also knock back Stansted expansion.
Mr Godden, speaking at a briefing for transport correspondents in London, said failing to expand the UK's airport capacity would harm the country's competitiveness.
He went on: "Such opposition to expansion does not recognise the real progress made by aerospace innovation to further cut aviation's impact on the environment.
"We hope that David Cameron is not prioritising some marginal constituencies near airports above the wider national economic interest."
Mr Godden said the Conservatives' policy position was "even more confusing" given that planes were now 75% quieter than they were 30 years ago and 70% more fuel efficient than they were 50 years ago.
Mr Godden continued: "The objections to airport expansion are therefore not based on reality and can only be a smokescreen for another unspoken reason to oppose new UK runways."
He said that other nearby European airports were already adding capacity and that the Conservatives opposition to expanding UK capacity was "particularly unwelcome for the UK economy in a highly-competitive global market for good business locations near excellent transport infrastructure."
Mr Godden said the Tory rail plans would be a welcome addition to the future transport network but "would in no way remove the need for new runways in London."