The door has been left open for Manchester Airports Group among other parties to bid for Stansted after Ryanair said it was excluded from the £1 billion takeover process.
Ryanair previously said it had held talks with potential bidders for the airport after it was asked to consider acquiring a minority stake as part of a consortium.
But BAA Stansted’s owner Ferrovial had now excluded Ryanair from the process, the airline said.
“Since Ryanair does not wish to prejudice other potential investors in Stansted, it has written to all investors/consortia it has held discussions with to advise them that Ryanair will not participate in the sale process or seek a minority stake,” the Irish no frills carrier said.
Around 70% of Stansted’s traffic – 18 million passengers last year – was with Ryanair, the airline added.
BAA declined to comment on the claims.
Ryanair chief executive Michael O’Leary said last month he would lobby to build a second runway at Stansted “as soon as possible” if he was successful in taking a minority stake in the UK’s fourth busiest airport.
Manchester Airports Group is now seen as frontrunner for Stansted but faces potential competition from an Australasian consortium, US banks, pension funds and Asian airport operators.
BAA finally decided to sell Stansted in August after losing a long running legal battle with the Competition Commission.
The company which owns Heathrow had been fighting a 2009 ruling by the commission that it must sell the Essex airport because of the lack of competition between London-area airports.