Members of the Irish Airline Pilots' Association working at Aer Lingus have voted in favour of industrial action as part of a pay dispute.
No date has been set for industrial action. The ballot was put to IALPA members last month.
The association has several weeks to serve strike notice on the airline if it wishes to target traffic over the busy August bank holiday weekend.
Aer Lingus has said that the airline has not received any notice of industrial action from IALPA and it does not anticipate any disruption to its schedule.
Pilots are understood to be seeking the payment of increments that were due to be paid in April of this year.
An agreed pay freeze expired in December 2012. Under that agreement, the pilots agreed to take a pay cut equivalent to the value of increments payable over a three-year period.
However, they continued to receive increments, which are pensionable, during the period.
A copy of the IALPA ballot, seen by RTÉ, stated that IALPA members "will engage in industrial action up to and including strike action in the event that Aer Lingus breach and/or continue to breach collective agreements which determine the pay, terms and conditions of such members".
Talks between the airline and IALPA are ongoing over the pay issue and also in relation to a deficit in the IALPA pension.
It is understood that this is in the region of €150m. The talks are being chaired by barrister Gerry Durkan.
IALPA is to have a meeting of its members this weekend to update them on progress from the talks. The next meeting between Mr Durkan and the two sides is scheduled for next month.
Sources close to the talks said that significant progress had been made on plugging the gap in the pilots' pension.
This is separate to the pension that operates for other employees at Aer Lingus, which is facing more significant deficit problems.
IALPA said it would not be making any comment while the current talks were ongoing.