Security guards at Heathrow Airport’s Terminal Five will strike for 10 days from March 31 over pay disputes.
The Unite union says more than 1,400 of its members employed by Heathrow will leave in a period spanning the school’s Easter break.
Employees of T5, used by British Airways, and those checking cargo entering the airport will take part in the promotion, which ends on Easter Sunday.
Heathrow says contingency plans will be put in place to keep the airport open.
In a statement, Heathrow said passengers can rest assured that the airport “will be open and operational despite undue threats of strike action by Unite”.
The company said it had proposed “an inflation-defeating 10% wage increase”.
But Unite says the offer doesn’t make up for years of wage freezes and cuts.
Union Secretary-General Sharon Graham says workers at Heathrow Airport are paid “poverty wages” while “the CEO and senior managers enjoy huge salaries”.
She said Unite members “simply can’t make ends meet because of low wages” and that they are striking “out of necessity not greed”.
“It is the airport’s employees who are fundamental to its success and they deserve a fair wage increase,” said the Unite boss.
Heathrow will likely have to move resources from other parts of the airport to Terminal 5 when the strike takes place.
The airport says the wage proposal offered is fair, and “threatening to ruin people’s hard-earned vacations with strike action won’t improve the deal”.
It said staff at Heathrow will receive a minimum of the London Living Wage, while the starting salary for a security officer would be £27,754, plus shift work and allowances, if the 10% offer is accepted.