Air travellers could face disruption next week as ground and cargo handlers threaten two days of strike action.
Workers at Heathrow, Manchester and Gatwick airports have backed industrial action from December 23 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 a 4.5 per cent pay rise – double the 2.25 per cent for other staff.
Britain’s largest union Unite 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.
In a statement Dnata said: "Dnata offered an increase in salary of 2.25% backdated to 1 July 2014 and a one-time payment of GBP175.
"This is a competitive package in excess of UK inflation and on par with, or exceeding the industry average. Following acceptance by the GMB union and based on the result of its own staff survey, dnata has in good faith, agreed to pay this award to its entire staff in the United Kingdom in its December salary, including Unite members."
The firm claims that less than 43% members of Unite voted in this ballot and less than 8% of its workforce voted in favour of industrial action.
“This minority has accepted the call for industrial action, which is expected to take place from 0400hrs on 23 December to 0500hrs on 25 December,” it added.
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,” said Hall.
Unite members include check-in staff, aircraft push back drivers, loaders and HGV drivers.
Dnata’s main customers include: Emirates, Virgin Atlantic, Qatar Airways, Qantas Airways and US Airways.