Ryanair Holdings Plc shares surged after the Irish discount carrier took another step toward de-escalating labor tension, saying pilots at all 15 of its bases in the U.K. have now voted to accept a pay deal.

The shares rose the most in a month after the airline said Thursday that pay increases of as much as 20 percent would take effect next week. Pilots at Ryanair’s biggest base, London Stansted, signed on after previously rejecting its offer.

The U.K. pay agreements remove one potential trigger for added labor strife at Ryanair, which agreed last month to recognize pilots’ unions across its European network after refusing to do so for years. Ryanair was forced to cancel thousands of flights because of scheduling errors last year that stoked tension with its pilots and gave unions support to press for recognition.

The shares rose as much as 3.9 percent intraday in Dublin. Ryanair was up 2.7 percent to 16.54 euros at 3:38 p.m. in Dublin, giving the company market value of 19.6 billion euros ($23.9 billion).

While the company has been engaged with unions including in the U.K., Ireland, Spain and Italy since December, no formal recognition agreements have been reached.

Negotiations with the British Airline Pilots’ Association are ongoing, the airline said, adding that the majority of flight deck crews in Ireland have already agreed to the pay increases, with the exception of its home base in Dublin. Talks with the Irish union, Forsa, are progressing “slowly,” the company said.

Most pilots at its Dublin base who have recently joined or are employed as contractors have accepted the pay offer, which Ryanair says lifts salaries ahead of low-cost competitors that operate similar Boeing Co. 737 fleets. The remaining 35 percent of its aviators in Dublin have refused to put the offer up for vote. Those pilots are no longer eligible for the increase this month, the company said.