About 300 security staff at Aberdeen and Glasgow airports will vote on strike action ahead of the summer holidays after rejecting a pay offer.
Unite the union said ICTS Central Search workers rejected a basic pay increase of 4% backdated to January and a £500 one-off payment.
They will be balloted on industrial action ahead of the summer holiday rush.
The union claimed workers have recently faced understaffing and were denied contractual breaks.
Unite said it had received growing reports of fatigue, exhaustion, and stress due to staff working beyond six hours with no break.
ICTS Central Search employs about 220 workers at Glasgow Airport and about 100 workers at Aberdeen Airport.
The workers deal with passengers directly in the security search areas and process them for flights. They also cover mobile patrols, control access posts, screen deliveries and deal with emergency services.
Unite general secretary Sharon Graham said: “Workers at Aberdeen and Glasgow airports have emphatically rejected ICTS’ miserable pay offer.
“The company is extremely profitable, and it can easily afford to make a far better offer to our members.
“Unite will fully back our ICTS Central Search members in their fight for better jobs, pay and conditions.”
The parent group ICTS (UK) Limited recorded its latest annual accounts with Companies House in March 2024, displaying profits of £3.2m in 2023, up from £2.3m in the previous year.
Pat McIlvogue, Unite’s lead industrial officer for the aviation sector in Scotland, said: “ICTS Central Search workers undertake safety and security critical tasks at Aberdeen and Glasgow airports. They deserve to be treated with respect.
“There should be a pay offer on the table which reflects the importance of their jobs. Without these workers the airports simply can’t operate.
“We now have no option but to move towards balloting around 300 members for industrial action ahead of the summer holiday rush.”
A spokesperson for ICTS Central Search said pay talks were ongoing.
They said: “Generous pay proposals have been tabled that would give staff a minimum of 4% increase as well as a lump sum payment.
“This is in addition to the 15-28% increases our staff have received over the last two years.
“We would like to reassure the travelling public that their security is our priority and there will be no disruptions.”