Airport operator BAA will still have to sell two of its UK airports following a provisional ruling today by the Competition Commission (CC).
The commission had ruled in 2009 that BAA would have to sell Gatwick and Stansted airports as well as either Edinburgh or Glasgow airport.
Since then there have been legal challenges by BAA to the ruling, which ended with the CC findings being upheld.
BAA has already sold Gatwick and today the CC provisionally concluded that the sale of the other airports should go ahead.
The CC said today it remained convinced the original sale decision was "the right one for passengers and airlines".
It added that Stansted should be sold first, with a "small overlap" between that sale and the sale of one of the Scottish airports.
BAA said today: "We will carefully consider the CC's provisional decision before making any decisions or further statements.
"We believe that there has been a material change in circumstances since the commission's report was published in March 2009."
The CC will now invite responses to its provisional decision before publishing a final verdict around May or June this year.
BAA also operates Heathrow, Southampton and Aberdeen airports. It had already decided to sell Gatwick before the 2009 CC ruling and the West Sussex airport was sold for £1.5 billion in 2009.
CC chairman Peter Freeman said today: "We remain convinced that the original decision to require BAA to divest three airports is the right one for passengers and airlines.
"We have re-examined that decision in the light of a significant subsequent development when the Government decided to rule out further runways at London's airports. Having examined the case closely, we are clear that many benefits will still arise without that expansion, by increasing competition and addressing detrimental effects from BAA's common ownership."
He added that there had been "no cause to alter our view on the need for either Edinburgh or Glasgow to be under separate ownership".
Making its ruling in 2009, the CC said it had found that at its south east England airport, BAA had shown "a lack of responsiveness to the interests of airlines and passengers that we would not expect to see in a business competing in a well-functioning market".
The CC also said that common ownership "adversely affects competition between Edinburgh and Glasgow".