(Bloomberg) -- Almost 1,000 workers at London’s Gatwick Airport set plans to walk off the job during two of the busiest weekends of July and August, adding to labor-related disruptions across Europe during the peak summer travel season.

The planned strike will total eight days, the Unite union said Friday after failing to reach agreement with ground-services companies at the airport south of the UK capital. Low-cost carriers EasyJet Plc and Wizz Air Holdings Plc, along with IAG SA’s British Airways, are among the hub’s biggest operators.

Concern is growing about a repeat of the chaos seen last year, when staff shortages roiled airline schedules, triggering long lines at airports and baggage pileups across the region. Air traffic controllers in France and Switzerland have already walked out over working conditions, and Eurocontrol, which manages air space in Europe, last week warned of more disruptions this summer over threatened strikes in Brussels.

Inevitable Delays

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At Gatwick, the UK’s second-largest airport, about 950 workers at ground-handling firms ASC, Menzies Aviation, British Airways-owned GGS and DHL Services will walk off on two successive weekends starting July 28 and Aug. 4, Unite said. Ryanair Holdings Plc, TUI and Westjet are among the other airlines set to be affected.

More than 4,400 flights are scheduled to take off from Gatwick across those days, according to aviation analytics firm Cirium. The industrial action will “inevitably cause severe delays, disruption and cancellations,” Unite said.

Security workers at London’s larger Heathrow airport called off strike plans after agreeing a wage deal last month. The UK has seen walkouts by train drivers, teachers, junior doctors and nurses as surging cost of living and high inflation take their toll.

Phil Lloyd, senior vice president of Menzies Aviation in the UK, said in a statement that Unite had rejected a pay increase of 11% for employees at Gatwick. He said Menzies has invited the union to return to negotiations and find an agreement which works for the company and its staff. BA, meanwhile, said its ground handling service GGS was surprised by Unite’s announcement after having discussions with them this week and was working with the union to find a resolution.

Gatwick officials are drawing up plans to support the airlines who have contracts with the third-party ground handlers to ensure flights run in line with schedules, a spokesperson for the airport said. TUI said it had notified customers about the strikes.

Wizz will seek to limit disruptions and will contact passengers, it said. Representatives for EasyJet, Ryanair and Westjet didn’t respond to requests for comment. TUI said it had notified customers about the strikes.

(Updates with responses from Gatwick, Wizz and TUI)

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