Check-in staff and cargo handlers at Heathrow, Gatwick and Manchester airports have voted to stage a two-day strike next week.
The proposed industrial action on December 23 and 24 threatens travel chaos at the peak of the Christmas getaway.
Workers at the three airports have backed strike action in a ballot by 83 per cent.
The dispute is over a "divisive" pay offer from ground handling company Dnata, which would see supervisors get 4.5 per cent rise, double the 2.25 per cent for other staff.
The Unite union has called on Dnata to enter into talks with conciliation service Acas to resolve the dispute. It said the company was seeking to create a workforce of the "haves" and "have nots" and warned that more than 460 members, based mainly at Heathrow, would go on strike if the issue was not resolved.
Unite regional officer Kevin Hall said: "Strike action is very much a last resort and our members are mindful of the potential disruption it could cause. But they feel frustrated with an employer that has refused point blank to go to Acas and negotiate in a sensible manner.
"Instead, hardworking staff have seen their supervisors enjoy a pay rise double the amount that was imposed on them.
"Our members are angry over the inequality being shown within Dnata and we would urge management to join us at Acas to reach a fair pay deal."
Dnata is one of Heathrow's biggest cargo handlers and one of the biggest ground handlers across Heathrow, Manchester and Gatwick airports.