Ryanair is to appeal a decision by an Italian regional court to stop Ryanair and Easyjet's low fare flights on routes between mainland Italy and Sardinia.
The Italian authorities blocked Ryanair's low fare flights between Rome and Alghero by imposing a public service obligation on the route in spite of Ryanair and Airone already operating year round flights between Rome and Alghero.
Ryanair claims the ruling breaks European PSO rules.
Ryanair further claims that the rules have also been abused by the Italian authorities because Alitalia is being allowed to fly on PSO routes to Sardinia when it did not even apply to operate them in the first place.
"It is astonishing that while Ryanair has been blocked from offering low fares between mainland Italy and Sardinia, Alitalia is being allowed to sell its high fares on PSO routes that it did not even apply for," said Peter Sherrard, Ryanair's head of communications.
"The PSO system in Europe is clearly out of control. It is being abused by national Governments to protect high fare flag carriers while at the same time blocking low fare competition," he added.