Aer Lingus says it has been able to re-accommodate, refund or rebook about 80% of passengers likely impacted by upcoming industrial action by pilots.
It identified over 240 flights over five days which are expected to be cancelled, affecting as many as 35,000 passengers.
The airline says it could also make last minute cancellations on the day of travel.
Aer Lingus pilots are set to start indefinite work to rule action from Wednesday.
An eight hour strike on Saturday is also planned.
Both sides in the dispute have left the door open for further discussions.
Pilots are taking action over a requested pay increase of nearly 24%.
The airline has offered just over half of this.
“The insidious nature of this industrial action has the capacity to result in much more cancellations over the coming weeks if it’s not resolved,” said Donal Moriarty, Aer Lingus chief corporate affairs officer
