Strike action by hundreds of workers at Heathrow Airport could hit football fans heading to the World Cup in Qatar, a union has warned.
Unite said 700 workers who work in the ground handling, airside transport and cargo side of the airport will go on strike for three days from 18 November.
It said the strike action would cause disruption and delays at Heathrow terminals 2, 3 and 4.
The staff, employed by Dnata and Menzies, are calling for higher pay.
"Strike action will inevitably cause disruption, delays and cancellations to flights throughout Heathrow, with travellers to the World Cup particularly affected," Unite regional officer Kevin Hall warned.
The World Cup is set to begin in Qatar on 20 November and the union said it expected Qatar Airways, which has put on extra flights for football fans, to be "hit heavily" by the strike action.
But Unite general secretary Sharon Graham said the union's members at Dnata and Menzies "are simply seeking a decent pay rise".
She added: "Both companies are highly profitable and can fully afford to make a fair pay increase."
The union said other airlines, including Singapore Airlines, Cathay Pacific and Emirates will also be affected.
Passengers travelling to the United States for the Thanksgiving holiday might also be hit.
A Heathrow spokesperson said: "We are aware of proposed industrial action from Dnata and Menzies colleagues at Heathrow, and we are in discussions with our airline partners on what contingency plans they can implement to support their ground handling should the strike go ahead."
The spokesperson added that the airport's priority is to ensure passengers are not disrupted by any shortages of airline ground handlers.
Alex Doisneau, managing director of Dnata UK, called the industrial action "disappointing" and "costly".
She said its staff have been offered a pay award which is "in line with inflation and among the best in the industry".
"We would like to reassure our customers, partners and passengers that we are implementing contingency plans to minimise disruption to our operations."
Menzies said the strike action "will benefit no one". Miguel Gomez Sjunnesson, executive vice president Europe at Menzies Aviation, said the firm was "ready and willing to continue pay discussions", and urged Unite to take part in the negotiations.
He added: "I also want to reassure our airline customers and their passengers that we have robust contingency plans in place should Unite elect to continue with unnecessary industrial action."
Queues, delays and cancellations frustrated thousands of travellers earlier this year.
