Ryanair said yesterday that, although current trading was in line with expectations, it remained cautious heading into the winter.

Nonetheless, the low-cost airline has announced plans to press ahead with the purchase of nine new Boeing aircraft worth more than $500 million (€419 million) for delivery in late 2007.

The airline said that higher fuel prices over the summer months had been partly offset by cost reductions in the company and a slightly more benign yield environment.

Passenger volumes and load factors also remained strong.

But it expects the fare differential between Ryanair and the flag carriers, which has widened in recent months as the latter have imposed fuel surcharges, to narrow as flag carriers are forced to lower their fares to compete.

"We therefore remain cautious but comfortable with our previous guidance for the remainder of this fiscal year as we anticipate strong load factors and passenger volumes but, as expected, at slightly lower yields," chief executive Michael O'Leary said.

The airline has said that it expects to deliver net profits of €295 million for the full year.

The decision to exercise options to purchase nine new Boeing 737-800s, while it sells five older models, will result in an increase of 151 aircraft in Ryanair's fleet to 234 aircraft by 2012.

The company has options over a further 179 aircraft for delivery between 2008 and 2014.

The airline, whose fuel costs are hedged through until next March, is taking a cautious approach to further hedging.

However, chief financial officer Howard Millar said that the airline planned to have most of next summer's fuel needs covered by the early part of spring.

Ryanair is also in ongoing discussions with the Dublin Airport Authority regarding the launch of up to 20 new routes from Dublin airport to continental European destinations.