Check-in staff, baggage handlers and cargo crew at UK airports are planning a 48-hour strike from 23 December
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.”