British Airways staff at London’s Heathrow airport are being balloted by the Unite union on whether to strike work over a dispute about restoring pay to pre-pandemic levels, in what might add to staffing woes facing airlines and airports this summer.

The union is seeking to reverse a 10% pay cut imposed during the pandemic, it said in a statement Monday. If the workers vote in favor of industrial action, the union expects strikes to occur in July, the statement said.

“BA has now reversed the pay cuts imposed on management but refuses to do this for our members,” Sharon Graham, the general secretary of Unite, said in the statement. “A strike by our members will make an immediate impact on the service to customers so I urge BA to get a grip and restore these workers’ pay immediately.”

BA called the ballot “extremely disappointing,” and said it had offered the customer service staff participating in the vote a 10% payment for this year and a commitment to hold talks next year, which were rejected. It said that while the group represents a small part of its workforce, it hopes to find a way to reach an agreement and will operate flights as planned.

Staff shortages have been the chief trigger for swathes of flight cancellations and chaos at airports as two years of travel curbs spurred by the Covid-19 pandemic give way to pent up demand for travel. BA has already pared back its timetable by 10% through October following disruption earlier in the year as it struggled to hire sufficient workers in ground-services roles.

In 2020, IAG SA-owned BA came under fire from unions and lawmakers for its initial plan to cut as many as 12,000 workers, although it eventually slashed 10,000 jobs and reached deals with various unions.

The vote, which will cover about 500 workers, will begin June 7 and close June 27, the union said. The GMB union, which also represents some BA workers, is also in the process of balloting for industrial action, Unite said.