Unite balloted around 275 staff at Edinburgh Airport, including members working in security, terminal operations and search areas.
It said 85% backed strike action on a 75% turnout, and it is now calling on airport chiefs to get back round the table with an improved pay offer to avert disruption during the summer period.
Unite said its members at Edinburgh Airport rejected an inferior pay offer to one made to staff at Gatwick, where a 12% increase plus a £1,500 one-off cash payment has been accepted by the workforce.
Edinburgh Airport said it had offered an 11% pay rise along with a £1,000 cost-of-living payment and has now made an improved offer to staff.
Unite general secretary Sharon Graham said: “Unite’s members at Edinburgh Airport have emphatically backed strike action. The pay offer on the table is nowhere near good enough and airport bosses know it.
“A realistic pay offer needs to be put on the table which values our members in the same way as our members at Gatwick Airport.
“Unite will always support our members in the fight for better jobs, pay and conditions.”
The union previously claimed members’ pay at Edinburgh Airport has been cut by around 10% in real-terms over the last seven years, and said workers are “prepared to fight for a better deal”.
An Edinburgh Airport spokesman said: “This is a disappointing decision from Unite, especially after we met the ask of our unions – an 11% pay rise along with a £1,000 cost-of-living payment. We have made an improved offer to staff, with a 50% increase in the cost-of-living payment proposed. This has not yet been balloted on.
“Unite is insistent on comparing this offer to the one made at Gatwick but the important context missing from that comparison pushed by Unite is that this 11% increase at Edinburgh Airport would be the third pay rise given to the team since 2020, representing an overall increase of 19.6%. In contrast, this is the first offer made by Gatwick in the same time frame – a point Unite purposefully fails to note.
“We have proposed a deal that is well above what has been offered to many other workers in Scotland and is well above inflation. We still have serious concerns about the integrity of the original ballot and the number of members that voted – concerns Unite have failed to address.
“We have made every attempt to avert industrial action and to agree a well-deserved pay rise for all of our hardworking employees, not just the minority who are Unite members. We remain open to negotiating in good faith with our unions and have agreed to participate in future talks.”