Flights have been grounded at Dundee Airport due to strike action amid a dispute over pay.
More than 120 members of the Unite union are protesting against Highlands and Islands Airport Limited (HIAL).
The workers involved include security staff, baggage handlers, ground crew and those involved in fire and rescue and administration.
As well as Friday, Dundee will close again to flights on Monday due to further industrial action.
The airport welcomes around 20,000 passengers a year.
Walkouts are set to take place across all of HIAL’s 11 airports this month.
Barra, Benbecula, Stornoway, Sumburgh and Tiree airports will be closed to flights on 21, 22 and 23 February.
Campbeltown, Dundee, Inverness, Islay and Wick John O’Groats are expected to operate as normal during the same period.
At Kirkwall, opening hours will be limited to 7.15am-1pm for inter-island flights only.
Unite predicts the action will impact different services, from mail not getting through to offshore workers not being able to get to work or return home.
Sharon Graham, Unite general secretary, stated: “Let’s be clear that the source of this dispute is due to the inflexibility shown by airport management and the Scottish government to pay these workers what they deserve.
“Unite will fully support our members in the fight for better jobs, pay and conditions across the Highlands and Islands.”
Shauna Wright, Unite industrial officer, added: “Unite’s industrial action will now cause widespread disruption.
“Local communities, workers and businesses should turn their fire on the Scottish government for ignoring these vital workers and allowing this dispute to escalate to a point where airports will now be fully closed.”
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HIAL, a private limited company, is wholly-owned by the Scottish government.
The Unite members rejected a 5% pay offer last year.
Earlier this week, members of a second union at HIAL also voted in favour of industrial action.
Prospect’s ballot involved firefighters and security staff.
Inglis Lyon, HIAL’s managing director, apologised for the disruption to services and urged those intending to travel on the strike dates to contact their airline.
He added: “The enhanced offer we presented maximised the flexibility within the Scottish government’s pay policy.
“However, we remain in dialogue with Transport Scotland [and] the trade unions in an attempt to resolve the matter.”