Workers at London's City Airport will be balloted for strikes in a row over pay and conditions.
The GMB union said ground staff would be balloted in the next few weeks over strikes because their pay has been frozen since 2008.
The staff are employed by an agency and provide check-in services for CityJet, Air France and KLM flights.
But the airport said it had made contingency plans and any strike would not affect passengers.
A statement on the company's website said: "Although disruption to any Air France, KLM, and CityJet services is not currently expected, contingency plans have been prepared to ensure passengers can travel as booked.
"Any action would not involve or affect any other airlines at London City Airport."
Stephanie Attwood, of the GMB, said: "If the members vote in favour there will be a strike in March."