The same ballot also saw 92.8 per cent of workers back taking action short of a strike as they fight for improved wages.
Unite has said it will confirm dates for industrial action at the 11 airports next week.
That could result in disruption for travellers at Barra, Benbecula, Campbeltown, Dundee, Inverness, Islay, Kirkwall, Stornoway, Sumburgh, Tiree and Wick John O'Groats airports over the busy festive period, with the prospect of fire and rescue staff along with security and administration workers taking part in any action.
The workforce has already rejected the offer of a 5 per cent pay rise. Unite general secretary Sharon Graham said: "Airport workers across Highland and island communities simply can't afford to live on their current wages. To then present them with what amounts to a significant pay cut at a time of rocketing living costs leaves them with no other course of action, but to take a stand.
"The Scottish Government and Hial have to act to deliver on pay or face a rural workforce crisis.
"Unite's members working across these 11 airports have emphatically backed industrial action and they will have their union's full support in their fight for better jobs, pay and conditions.
"We urgently need Hial and the Scottish Government to get round the table. It's an imperative that the relevant parties work together to save rural communities and retain jobs in the Highlands and islands.
"With the necessary political will, we believe that our members' pay, terms, and conditions across Hial airports can be improved."
A Hial spokesman said: "Unite's media statement is unhelpful as it does not explain what industrial action will take place, or the dates it will commence.
"We recognise the challenges our colleagues face due to inflationary pressures and the cost-of-living crisis. Nonetheless, we are disappointed that they have voted for industrial action. The enhanced offer we presented maximised the flexibility within the Scottish Government's pay policy.”