Some flights at the Dublin, Cork, Knock and Shannon airports have been cancelled as Aer Lingus pilots are due to go on strike on Saturday.
The pilots began a work-to-rule on Wednesday and the strike action, which will last for eight hours, starts at 05:00 local time.
This is part of an ongoing dispute over pay.
The Irish Airline Pilots’ Association (Ialpa) previously called for a 24% pay rise for members.
The pilots’ picket line will be at the entrance to Dublin Airport.
Aer Lingus say there are “a number of options” for passengers affected.
The airline has now cancelled almost 400 flights as a result of the indefinite work-to-rule and strike action by pilots.
