Ryanair chief executive Michael O’Leary has guaranteed the airline will not impose fuel surcharges, but said fares may have to rise to follow increases from competitors.

Speaking at the airline’s annual general meeting in Dublin on Thursday, Mr O’Leary said that if the price of oil remains high, some cost will be passed on to customers.

He said: “Guaranteed, we will not impose fuel surcharges, regardless of the cost of where oil goes to, but our competitors will impose fuel surcharges.

“Now, our fares may follow up behind somebody else’s fuel surcharge, but we’re not levying fuel surcharges.

“Like, we’re a pretty good airline, but we’re not f****** geniuses.

“If oil prices rise materially from 80 dollars dollars a barrel to 140 dollars a barrel, airfares are going to rise, but we’re not going to be levying fuel surcharges, guaranteed.”

Mr O’Leary said Ryanair would overtake American Airlines, to become the largest passenger airline in the world “in the next four or five years”.

He said the airline’s fares may rise ​slightly ‌this winter after the decision to cut some ​winter ‌flights. But following decreases of “very low single digits” between July and August, he is hopeful increases will be “flat-ish”.

He said: “If you remember last year, our average fares went up 10% and we thought this year they’d go up by another 4% or 5%.

“We put that down to the fact that everybody’s a little bit more price sensitive, particularly with the uncertainty in the Middle East and higher price of oil.

“It’s a little bit better than that. We’ll be down very low single digits in the second quarter, which is the September quarter.

“In the last month, there’s been a slight upturn in fares. Nothing significant, but we think there’s a possibility towards the end of the year that fares will be flattish through the winter.”