Pilots at Aer Lingus are currently balloting for full strike action, which would include a full shutdown of all Aer Lingus services.
This is in support of Aer Arann pilots, who are threatening to strike beginning on Tuesday in a row over pay.
The Aer Lingus ballot is under way this evening and will continue tonight.
Aer Arann and representatives from the Irish Airline Pilots' Association began talks this evening aimed at averting their planned strike.
In a memo to all staff yesterday, a copy of which has been seen by RTÉ News, Aer Arann said that if the strike goes ahead, it faced the prospect of cancellation of its entire schedule, suspending certain flights or running a limited schedule.
The company said it could not afford to hire outside workers.