Aer Lingus slashed its annual profit forecast on Thursday after the threat of strike action by cabin crew significantly damaged its bookings for the peak summer season.
The Irish airline has been rocked by a bitter and public row between management and cabin crew over rosters in recent months.
Cabin crew staged a strike over a busy public holiday weekend in June that disrupted 28,000 passengers.
Up to 80,000 passengers could have been hit by a further two-day strike planned for next week, but it was called off late on Wednesday.
"The threat of this strike has caused significant damage to Aer Lingus' trading and forward bookings for several months into the future," the company said in a trading statement Thursday.
"Aer Lingus now expects that its 2014 operating profits (before net exceptional items) will be 10 percent to 20 percent lower than last year."
The forecast would put the airline's profit between 49-55 million euros, down from 2013's operating profit of 61.1 million euros ($82.7 million).
But the airline warned those figures assumed no further strikes were threatened.
It added: "The outcome will depend in part on the speed with which we can win back customer confidence."
The airline's shares were down more than 3.0 percent at 1.44 euros in late afternoon trading on the Dublin stock market.