Irish based Ryanair pilots who are members of the Irish Airline Pilots’ Association have voted overwhelmingly to back industrial action.
The union said it would write to management early next week to outline plans for action unless the airline agrees to union pay proposals by Monday.
It says the airline is in a healthy financial position and can fairly reward its pilots.
Ryanair is taking legal action against outgoing chief operations officer Peter Bellew, who is continuing to work out his notice at the Irish airline.
It emerged last month that rival carrier Easyjet had poached Mr Bellew from Ryanair and that he was leaving the Irish airline at the end of this year.