Airport staff in pre-Christmas strike
Check-in staff, baggage handlers and cargo crew at UK airports are planning a 48-hour strike from 23 December, the Unite union says.
The union said more than 1,500 workers at Swissport, the world's largest ground and cargo handler, would walk out following a long-running dispute over pay and conditions.
Unite said the action, which will hit Christmas travel, was "a last resort".
Swissport said it was making plans to "minimise disruption" to passengers.
It is unclear exactly how many airports will be affected, but airlines at Edinburgh, Aberdeen, Glasgow, Leeds/Bradford, Liverpool, Newcastle, Heathrow, Stansted and Manchester airports all employ Swissport staff.
A spokesman for MAG, owners of Manchester, Stansted, East Midlands and Bournemouth airports, said: "We are aware of this potential action and are contacting the airlines which use Swissport to understand their contingency plans to minimise any disruption were the strikes to go ahead."
A spokesman for airline Ryanair said: "All of our flights to and from the UK are scheduled to operate as normal.
"Should this action proceed, our flights may operate with hand-luggage only and we will update customers accordingly."
A Heathrow spokesman said they expected "minimal impact for passengers" from the action.
Swissport is one of several companies providing ground-staff services across the UK.
According to Unite, members voted by 62.5% to reject a 4.65% three-year pay deal for 2015-2017, which the union argues "barely" keeps pace with inflation.
It said workers were also angry that "detrimental" changes to terms and conditions had been linked to the pay deal.
Conditions included freezing overtime payments for the foreseeable future and restructuring pay.
Unite's national officer for civil air transport, Oliver Richardson, said: "Our members are only taking this industrial action as a last resort in a bid to reach a fair settlement - our members have not had a pay rise since 2014.
"When you break down the headline figures - 1% in 2015, 1.25% in 2016 and 2.4% in 2017 - they are barely keeping up with inflation."
Both Unite and Swissport said they would be open to talks with the conciliation service Acas to resolve the dispute.
Separately, British Airways cabin crew based at Heathrow airport are to strike on Christmas Day and Boxing Day in a row over pay and conditions.
The action, backed by the Unite union, could involve up to 4,500 staff on "mixed fleet" contracts who joined the airline since 2010.