Ryanair boosted its passenger target for the year on Monday and said its full-year profit would be at the higher end of its earlier guidance on strong summer bookings.
But the Irish airline, Europe's largest by passenger numbers, said it would cut fares sharply during the winter and that competitors could respond aggressively.
Passenger numbers will grow to 103 million this year from 90.6 million last year, the company said in a statement. It increased its earlier target of 100 million passengers due to plans to fill more seats per plane and ground fewer aircraft in the winter.
Profit after tax for the year to the end of March 2016 will be at the higher end of the company's forecast of between 940 million (666 million pounds) and 970 million euros given in late May, it said.
But Ryanair remains cautious as competition could heat up this winter as the company takes full advantage of falling fuel prices, said Chief Executive Michael O'Leary.
"This guidance, which is 12 percent ahead of last year's profit, is heavily reliant on the final outturn of second-half fares over which we currently have almost zero visibility," O'Leary said.
Ryanair had said in May that it planned to cut fares between October and March by between 4 percent and 8 percent, but chief financial officer Neil Sorohan said that the fall would likely be closer to 8 percent as fuel savings kick in.
The airline plans to ground 40 planes this winter compared to 50 last year and it expects to fill 90 percent of seats, up from 88 percent last year, he had said.
Follow us on Twitter: @CNBCWorld