LONDON (AP) — Hundreds of thousands of British vacationers face potential disruption to their travel plans at the start of the school summer holidays, after almost 1,000 workers at London's Gatwick Airport voted to strike in a dispute over pay.

The Unite union said Friday that members, including baggage handlers and check-in staff, who are employed by four private contractors will walk out for four days from July 28 and again for a subsequent four-day stretch from Aug. 4.

The union said the action will “inevitably” cause disruption to flights at the height of the summer holiday season after the school year has ended. The airlines affected are British Airways, easyJet, Ryanair, TUI, WestJet and Wizz Air.

Gatwick, which is just south of the U.K. capital, is London's second-busiest airport behind Heathrow, with a particular focus during the summer to Europe's beach resorts in the Mediterranean.

A total of 4,410 flights are scheduled to depart Gatwick across all the strike days, equating to more than 840,000 seats, according to aviation data company Cirium.

Those involved in the dispute are employed by ASC, Menzies Aviation, GGS and DHL Services, which conduct outsourced operations for airlines including ground handling, baggage handling and check-in. Unite said it has been in negotiations with the four companies since January.

“As part of Unite’s unyielding focus on the jobs, pay and condition of its members, the union has drawn a line in the sand and is committed to eradicating the scourge of low pay at the airport," said Sharon Graham, the union’s general-secretary.

Britain has witnessed an array of strikes over the past few months as workers across various sectors try to get wage raises that at least keep pace with inflation. Though inflation has fallen from its peak, it remains high at 8.7%. Unite said the majority of workers who are set to strike are paid an average of under 12 pounds ($15.50) an hour.

Gatwick, like other airports in Europe, is already suffering major disruption because of air traffic control restrictions as a result of strike action, staff shortages and airspace closures related to Russia's full-scale invasion of Ukraine.

“We are aware of the recent ballot result and will support our airlines with their contingency plans to ensure that flights operate as scheduled," a spokesperson for the airport said.