Almost 500 Aer Lingus pilots have served strike notice on the company over the terms and conditions being offered as part of a plan to recruit new pilots in Belfast.
The Irish Airline Pilots Association is accusing the airline of breaching collective agreements by offering less favourable terms to the new pilots.
The association says it will members will go on strike next Tuesday and Wednesday unless the situation is changed.
Spokesman Michael Landers says it is unacceptable that Aer Lingus is seeking to cut costs by offering Belfast pilots less favourable terms than those enjoyed by Dublin pilots.