Aer Lingus has also issued a profit warning, and is the second European airline in two days to do so, blaming declining bookings on the threat of ongoing strike action by cabin crew.
Aer Lingus stated that the industrial action by the Impact union had caused "significant" damage to its trading and ticket bookings for several months to come.
The airline also said that the effect had been particularly noticeable in recent days following increased media coverage of the industrial action.
"Aer Lingus now expects that its 2014 operating profits will be 10% to 20% lower than last year. The outcome will depend in part on the speed with which we can win back customer confidence," it said.
Impact indicated late Wednesday that it would postpone a planned strike action on June 16th and 18th to allow time to consider an interim recommendation that will be issued by the Irish Labour Court on Thursday.
Aer Lingus shares were down 4.2% at €1.427 early on Thursday.