Planes at Heathrow Airport
Justine Greening has said the government remains opposed to a third runway at Heathrow, despite calls from Conservative MPs for a change of heart.
The transport secretary said expanding Heathrow was "not right" for the UK and other options needed to be considered - including building a new hub airport.
Some ministers have reportedly urged a rethink amid strong business support.
And backbencher Tim Yeo said David Cameron must show whether he was a "man or a mouse" by backing the idea.
The coalition agreement between the Conservatives and the Liberal Democrats rules out any expansion of Heathrow before the next election, while Labour also currently opposes the idea of a third runway at the UK's largest airport.
But a consultation on future air capacity in south-east England has twice been delayed amid reported divisions within the coalition and Conservative ranks.
Ms Greening, whose Putney constituency is on the Heathrow flight path and who personally campaigned against a third runway before becoming a minister, said the coalition agreement was "very clear" in its opposition to a new runway at Heathrow.
"I don't think any of the facts have changed around a third runway," she told Radio 4's Today programme. "The facts remain as they were at the time of the election."
She said concerns over increased noise, pollution and disruption to the surrounding area had not been addressed and suggested that a new runway would not be long enough to accommodate new, larger planes and would be full "within a few years".
"There is now a cross-party consensus that a third runway... is not the right thing for Britain," she said.
"Make no mistake - a third, short runway will not be a long-term solution to our country's hub capacity question that we currently face.
"Britain deserves better and deserves a much longer-term aviation plan than it has had in the past."
The idea of a new airport - like one proposed by London Mayor Boris Johnson in the Thames Estuary - was "clearly one of the options", she added, as well as existing airports working more closely together.
Asked about her own position, Ms Greening said she would find it "difficult" to remain in government if it reversed its position on the issue, while insisting this was a "hypothetical" situation.
In March, reports suggested Chancellor George Osborne was pushing for the runway idea to be reconsidered.
Since then, a number of Tory MPs have warned that the UK is being left behind in aviation, saying a new runway is needed to boost trade and competitiveness.
Housing Minister Grant Shapps, tipped for promotion in a reshuffle, said on Friday that "all the options need to be considered while being mindful of our election manifesto".