Ryanair boss Michael O'Leary has admitted that the low-cost airline was braced for a difficult winter as austerity measures and the eurozone crisis hit demand.
The Dublin-based carrier, which operates more than 1,500 flights a day across 28 countries, is expecting traffic growth of 1% between September and March, down from 7% this summer following winter capacity cuts, Mr O'Leary said.
The outlook came as the airline, which expects to carry 79 million passengers this year, reported an 11% rise in revenues in the quarter to June 30 to 1.3 billion euro as 6% traffic growth combined with a 4% rise in average fares.
However, Mr O'Leary said a 27% surge in fuel costs was behind a 29% slide in underlying pre-tax profits to 99 million euro in the period.
Ryanair reported a 15% rise in ancillary sales - which includes baggage and administration fees, as well as in-flight food and drink - to 286 million euro. Ancillary sales now account for 22% of all revenues.
The carrier, which has a fleet of 294 planes, said growth in the first quarter was dampened by the EU-wide recession, austerity measures and also heavy discounting at new bases including Cyprus, Denmark and Hungary.
The airline will see its 51st base open in Maastricht, in Holland, in December, and it hopes to add up to two new bases later this year.
Mr O'Leary hit out at the Spanish government for hiking airport taxes at the start of July and welcomed a Court of Appeal decision to dismiss BAA's latest appeal against a Competition Commission recommendation to sell Stansted Airport.
Ryanair mounted a fresh bid to seize control of rival Aer Lingus last month by tabling an offer valuing the company at around 694 million euro. The airline, which already owns a 29.8% stake in Aer Lingus, requires approval from EU regulators for the deal to go ahead. A previous takeover attempt in 2006 was rejected.
Ryanair said it would be "inappropriate" to comment while the airline is engaging with regulators.