Ryanair is set to scrap plans to reduce its fleet in Ireland after pilots there unanimously backed a deal negotiated by their trade union that provided a breakthrough in the airline's efforts to quell staff protests.

Europe's largest low-cost carrier suffered its worst ever strikes this summer, but reached agreement on issues including transfers and promotions with the Irish union two weeks ago and said it was hopeful it could secure deals in other markets soon.

In a statement after the Forsa/IALPA union published the ballot result on Wednesday, Ryanair welcomed the vote and said it would ask its board to reverse a plan to reduce its Dublin fleet by six aircraft.

In July, Ryanair said it would reduce the winter fleet in its home base to 24 from 30, moving aircraft to its Polish airline, Ryanair Sun, which it said was enjoying rapid growth.

The fleet reduction threatened the jobs of over 100 Dublin pilots and more than 200 cabin crew who were issued with 90-day protective notices.

The board will meet to discuss the development in the coming days, it said.

After publishing details for the first time of the agreement it described as a "first step" towards providing fairness for pilots, the union said the flexibility on base transfers and promotions would end the "sole control" exercised previously by management over pilots' careers.

"While our members fully respect Ryanair's operational model, they no longer accept the company's highly problematic employment model. After decades of declining terms and conditions, pilots in Ryanair have now firmly found a unified voice," Captain Joe May, a spokesman for IALPA, said in a statement.

Ryanair shares were 1.3 percent lower at 13.59 euros by 1430 GMT.