Ryanair said yesterday that if Edinburgh Airport's new owners fail to stop the airline's planned withdrawal of eight routes in October, some of the business may be switched to Prestwick.

Michael Cawley, deputy chief executive, told The Herald: "If we go ahead with the cuts in Edinburgh as planned, it is very likely we will divert a modest amount of them to Prestwick."

The Irish low-cost airline has cut five of its 35 routes at Edinburgh Airport already this year and is threatening to cut another eight unless it can renegotiate landing charges.

It is already launching a new Polish route in October at Prestwick, where it has reduced frequencies but still has 25 routes and a maintenance base employing over 250.

Mr Cawley said the new consortium owners at Edinburgh had no doubt been busy since the deal went through a month ago.

"We are certainly available to speak to them at any time, but we are not staying awake at night. We have made our plans. They know our terms and we are not going to change our mind."

The affected routes are to Bratislava, Bremen, Frankfurt, Fuerteventura, Gothenburg, Kaunas, Lodz and Poznan, which Ryanair has claimed would threaten 500 jobs at Edinburgh. The airport was acquired on April 22 by Global Infrastructure Partnership.

Mr Cawley said Prestwick had been "damaged severely" by airport passenger duty (APD) over the past few years and he was therefore "not surprised" at the recent fall in the airport's valuation, revealed last week in a report for its New Zealand owners Infratil.

Ryanair was posting a net full-year profit for 2011 of €503 million (£405 million), a rise of 25%, but said that was likely to fall this year by up to 25%.

Michael O'Leary, the group's combative chief executive, said: "We remain concerned about next winter as we have zero yield visibility but expect recession, austerity, currency concerns and lower fares at new and growing bases in Hungary, Poland, provincial UK, and Spain, will make it difficult to repeat this year's record results."

He said the profit rise alongside 5% traffic growth during a year of higher oil prices and deep recession in Europe was a "commendable result".

Mr O'Leary said three European airlines had already folded this year with a fourth, BMI Baby, under threat.

"We expect more European failures in 2012, as higher oil prices and recession continue to expose failed airline models as well as subscale or peripheral carriers."

He said Ryanair had responded "tactically" by opening a new base in Budapest, and expanding bases in Spain, Scandinavia and the UK.

He added: "Despite a rising number of airline failures and record airline losses, many of Europe's governments treat aviation [and airline passengers] as a cash cow to fund their taxation and/or policy failures. It is extraordinary at a time when the European Union is promoting growth, that individual EU governments wilfully ignore the reality that taxing air travel will damage traffic, tourism and job creation, particularly in the weaker EU regions."

Mr O'Leary accused the EC's competition directorate of continuing a "misguided vendetta" against the company, with 18 separate investigations of mainly Ryanair traffic growth agreements at low-cost regional airports.

He said Ryanair's balance sheet remained "one of the strongest in the industry" despite a proposed £390m special dividend later this year.