Ryanair has seen profits fall by 29 per cent, to €1.02 billion, for the year to March 31st as the price of seats fell and the cost of fuel rose.
The low-cost carrier said worse could be to come this summer as over capacity in Europe pushes carriers to cut prices further.
The headline figure also excludes a loss of €139 million at Austrian carrier Lauda which Ryanair took over last year.
Shares in the airline fell by five per cent following the release of the results, to €10.2 per share.
Ryanair chief executive, Michael O’Leary, said: “Short-haul capacity growth and the absence of Easter in quarter four led to a six per cent fare decline, which stimulated seven per cent traffic growth, to over 139 million.
“Ancillary sales performed strongly, up 19 per cent to €2.4 billion, which drove total revenue growth of six per cent to €7.6 billion.”
For the coming financial year, the carrier said it was “cautious” on pricing and had “zero” visibility for the second half of 2019.
Faltering economies in Europe and the possible impact of Brexit could take a toll, Ryanair said.
The carrier added that, while bookings in the first half of this year were slightly ahead of last year, “fares are lower and we expect this trend will continue through 2019”.
The airline estimates that profits could range between €750-€950 million for financial 2019.
Ryanair is delaying deliveries of five of the Boeing 737 Max planes, which have been grounded because of two fatal crashes, but said it had the “utmost confidence” in the aircraft.