Europe's short-haul carriers have struggled in recent months with overcapacity and Britain's vote to leave the European Union, with low-priced rivals Wizz and easyJet both trimming their annual profit forecasts in recent weeks. This uncertainty, it said, will continue to present a challenge for its business in the final months of its current financial year and into financial 2018.
Barring such unforeseen events, Ryanair said it would carry around 119 million passengers in FY17, up 12% on the previous year's figure of 106 million.
Chief executive Michael O'Leary - who strongly backed a Remain vote - said this impact was "exacerbated by the sharp decline in sterling following the Brexit vote".
"The airline derives about a quarter of its earnings in pounds so the collapse in sterling explains a good deal of the fall in profits", he added.
Budget airline Ryanair reported a drop in third-quarter profit on Monday as it sounded a cautious note on the outlook for 2017.
Ryanair expect to decrease ticket prices further heading into their fiscal fourth quarter, with prices falling as much as 15 percent. "It seems clear that pricing will continue to be challenging, and we will respond to these adverse market conditions with strong traffic growth and lower unit costs", the carrier said. Fuel costs per passenger were down 20% in the quarter.
It blamed downward price pressure on Brexit uncertainty, a weaker pound, and the drop in demand for destinations like Turkey, Egypt and North Africa, all of which have experienced terrorist attacks in recent years.
The airline said that while there may be opportunities to expand at some United Kingdom airports, it expected to grow more slowly than planned there.
The carrier said load factors rose 2% to 95%, a third quarter record.
The airline launched 95 routes and five bases during the period in Bucharest, Hamburg, Nuremberg, Prague and Vilnius.
"Ryanair expects to announce some additional United Kingdom and European Union growth deals in the coming months, as airports compete for our growth against the hard backdrop of Brexit uncertainty", the airline added.
Europe's busiest short-haul airline, whose growth target aims at expanding from the 106 million passengers a year it carries today to 180 million by 2024, said that the price environment for air fares remained weak.