Ryanair Holdings Plc’s summer of simmering industrial strife is set to come to a head next week after the company’s Irish pilots said they’ll walk out on the same days as U.K. crews following the collapse of pay talks.

The double-whammy threatens to shut down flights at bases including London Stansted, Europe’s biggest discount hub, in the run up to Britain’s August bank holiday—traditionally the busiest weekend of the year for U.K. travel.

Chief Executive Officer Michael O’Leary is grappling with a slew of pay disputes after recognizing unions two years ago. Labor relations deteriorated further when he said hundreds of jobs must go and bases close to cope with a possible no-deal Brexit and slower growth after the grounding of Boeing Co.’s 737 Max.

Here’s a rundown of the labor spats facing Europe’s biggest low-cost carrier:

Ireland

Labor group Forsa said late Wednesday that Ryanair pilots would strike for 48 hours from 12:01 a.m. on Thursday, Aug. 22, after the group failed to make a substantive pay offer. The airline blamed the union for collapsing mediated talks, and said that with fewer than half its Irish pilots represented, the action has “no valid mandate.”

Ryanair’s biggest hub in Ireland is in Dublin, which while smaller than Stansted carries a high profile as the airline’s home base. Irish politicians in the capital have often weighed in against the company on labor issues.

U.K.

Members of the British Airline Pilots’ Association plan to strike on the same two days, when thousands of Britons are booked to fly ahead of the Aug. 26 public holiday. The U.K. is the carrier’s biggest market and the action could have more impact “than any other the company has weathered,” Sanford C. Bernstein analyst Daniel Roeska wrote in a note. The hit on profit depends on how long the dispute lasts and if the carrier has to pay compensation, he says. The union, which plans a further three-day action in September, has offered to meet the airline for talks along with a mediator.

Portugal

Cabin crew and ground staff plan a five-day strike starting next Wednesday, overlapping with the pilot walkouts. While the action is likely to curtail travel, it has the potential to gum up the movement of passengers within airports. The SNPVAC union says Ryanair is failing to comply with rules regarding the payment of holiday and Christmas subsidies and the number of vacation days. The union has also said the carrier plans to shut its base in Faro.

Spain

Flight attendants at Ryanair’s 13 Spanish bases plan to strike on 10 dates in September after the carrier said it would close two hubs in the Canary Islands and consider shuttering one in Girona, according to the SITCPLA and USO unions. The labor groups said Wednesday they’ll meet with management in the next few days and formalize the walkout if no agreement is reached.

Austria

In a rare outbreak of labor peace, Ryanair halted moves to cut 30 pilot jobs at the Laudamotion unit it acquired last year after staff approved to contract revisions including longer working hours and more rigid vacation dates, the Kurier newspaper reported Monday. Andreas Gruber, the unit’s CEO, had warned costs were too high to compete with Wizz Air Holdings and Deutsche Lufthansa AG and dangled the prospect of Ryanair shrinking Lauda.

Ryanair shares traded 0.8% lower at 8.82 euros as of 11:51 a.m. in Dublin. The stock is down 18% this year after slumping close to 30% in 2018 amid widespread labor unrest following the company’s initial recognition of unions.