The European Commission, which is investigating the provision of unfair subsidies to Ryanair at Belgium's Charleroi Airport, has received a number of fresh claims against other airports.
The commission, which is expected to conclude its investigation at Charleroi before the autumn, has said it will begin to examine the claims after it issues its finding.
Commission transport spokesman, Mr Gilles Gantelet, would not disclose which other airports had been identified. "During the investigation we have received information on other airports besides Charleroi," he said.
Charleroi airport is owned by the Wallonian regional government. Yesterday, Ryanair said it was confident and expecting an early and positive decision in the Charleroi case.
Ryanair has presented a dossier of documents to the European Commission to prove the legitimacy of its financial relationship with the airport.
The commission held public consultations as part of its investigation into arrangements at Charleroi and follows a meeting between Ryanair chief executive Mr Michael O'Leary and the Transport Commissioner, Ms Loyola de Palacio.
Mr O'Leary said at that time that Ryanair could provide documentary evidence that the arrangements it enjoyed at Charleroi had also been open to other airlines. It has claimed that it did not receive illegal state aid when establishing its hub there.
Ryanair has said it was a rival airport, the national hub outside Brussels, which made the initial complaint.
Mr Gantelet declined to say who had brought the new complaints or which airports they had levelled their allegations against.
But he said no new investigations would begin until the Charleroi inquiry reached a conclusion. A source close to the airline industry said complaints had been brought in France, Germany and Sweden.
The complaints include one made against France's Strasbourg airport by Brit Air, a subsidiary of Air France. The airport serving the French town of Pau has also been targeted, both by the Chamber of Commerce in nearby Tarbes and by charter airline Air Mediterranee, which have launched actions against Pau. - (Additional reporting by Reuters)
