"It is complete nonsense to say that we are looking at further development," said a spokesman for the airport.
"We gave legally-binding agreements that we would not develop further south of Cheshire," she said.
But Clr Laurence Hobday said this week that one of the original options for the second runway could in fact be used to develop a third.
"They may not be planning a third runway, but a relocation of one of the existing runways could be on the agenda," he said.
At present, the two runways are too close together to allow simultaneous take-offs and landings.
But 'moving' the first runway to a site parallel to the second runway would allow for simultaneous flights - and extra revenue for the airport.
"If they want economic growth the airport will have to develop," said Clr Hobday.
"It means inevitably they must expand."Yesterday (Tuesday), the airport refused to reveal the amount of land it owned around Mobberley and Ashley because of 'confidentiality agreements' with farmers who had sold land.
But according to a map - leaked to the Knutsford Guardian - a significant amount of farm land south of Mobberley, into Ashley and Rostherne, is now 'managed' by the airport.
This week, the airport denied that any new plans would be looked at - at least until 2015.
"We have made no secret of the fact that until 2015 we can cope with up to 40.7 million passengers," said the spokesman.
"That is as far as our plans currently stretch," she said.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article