Ryanair has lowered its profit guidance for the year.
It expects profits of between €1.0bn and €1.1bn, down from its previous range of between €1.1bn - €1.2bn.
Chief executive Michael O'Leary blamed lower than expected air fares, saying that there is too much capacity in the short haul European air market this winter.
"We cannot rule out further cuts to air fares and/or slightly lower full year guidance if there are unexpected Brexit or security developments which adversely impact yields between now and the end of March," he said.
"We believe this lower fare environment will continue to shake out more loss making competitors, with WOW, Flybe, and reportedly Germania for example, all currently for sale," he added.