Asked if Ryanair's fares could fall further, Michael O'Leary told French weekly Le Journal Du Dimanche: "Absolutely, by at least 10-15 percent over the next two years. In 2016 our average air fare could be at 40 euros".

"This will come as we pass on lower oil prices. We will also continue to grow passenger numbers and cut our costs," he said.

O'Leary said the average price of a Ryanair's ticket was currently 46 euros, which he said compared with around 170 euros for a short-haul flight within Europe on other airlines.

(Reporting by Dominique Vidalon, editing by William Hardy)