Airport operator BAA lost its latest challenge today against a decision forcing it to sell Stansted Airport in Essex.
The appeal by the Spanish-owned company was rejected by three Court of Appeal judges in London.
In 2009 the Competition Commission (CC) ruled that BAA must sell Stansted in Essex and two of its other UK airports.
BAA has since mounted a series of unsuccessful legal challenges against the decision.
Earlier this year BAA lost an appeal before the Competition Appeal Tribunal.
In their ruling today Lord Justice Mummery, Lord Justice Rimer and Lord Justice Sullivan dismissed BAA's challenge against the decision of the appeal tribunal.
Since the CC decision, BAA has sold Gatwick Airport in West Sussex and, faced with having to dispose of either Edinburgh Airport or Glasgow Airport, it has opted to sell Edinburgh.
The Competition Commission (CC) said it welcomed the Court of Appeal's decision.
Laura Carstensen, chairman of the BAA Remedies Implementation Group, said: "We are pleased that our decision on Stansted Airport has once again been upheld.
"It remains the right decision in the interests of passengers and airlines and it is surely now time for BAA to accept the verdict and proceed with the sale."
BAA said in a statement: "We are disappointed that the Court of Appeal has ruled in favour of the Competition Commission.
"We will now consider its judgment carefully and we intend to submit an appeal to the Supreme Court."