As many as 100 workers at Aberdeen International Airport (AIA) are set to be balloted on strike action ahead of the busiest season of the year.
Security workers at the airport, along with around 220 from sister airport Glasgow, rejected a pay offer from employer ICTS.
A 4% pay increase backdated to January 2024, as well as a £500 one-off payment was rejected "emphatically", according to union bosses.
The staff play a vital role in airport security, carrying out mobile patrols, screen deliveries and deal with emergencies.
But Unite claims staff "routinely" work more than six hours without a break, which is in breach of Working Time Regulations.
Could strikes close down airports?
That's one of the threats being put the airports way from the unions.
Pat McIlvogue, Unite’s lead industrial officer for the aviation sector in Scotland, said: "Without these workers the airports simply can't operate.
He added: “There should be a pay offer on the table which reflects the importance of their jobs.
"We now have no option but to move towards balloting around 300 members for industrial action ahead of the summer holiday rush."
'There will be no disruptions'
However, despite the seeming threat that industrial action could close down airports this summer, a spokesperson for ICTS said: "We would like to reassure the travelling public their security is our priority and there will be no disruptions."
They continued: “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."
An AIA spokesman said: “This is a matter for ICTS as the direct employer involved.”