Unite workers at Hial walk out in pay dispute
Members of the Unite union at Highlands and Islands Airports Ltd (Hial) have walked out in the first of two strikes taking place this month.
Hial said the action had closed its Barra, Benbecula and Sumburgh airports and limited operations at Stornoway and Kirkwall.
It said Campbeltown, Dundee, Inverness, Islay, Tiree and Wick John O'Groats were open as normal.
The strikes on Monday and Thursday are part of a pay dispute.
Workers previously rejected a 5% offer which Unite said was "unacceptable" with inflation at a 40-year high.
The action involves fire and rescue, security and administration staff.
Wendy Dunsmore from Unite told BBC Scotland: "We are not targeting Christmas deliberately. We have been speaking to the employer time and time again and the workers are now forced to take this action.
"It's really, really disappointing for travellers, it's really, really disappointing for the communities but it's very disappointing for staff that are forced to do this."
Hial said Unite had confirmed that its members would respond to any medical and other emergencies on both days.
Inglis Lyon, Hial's managing director, previously apologised to passengers and airlines.
"Whilst recognising the financial challenges our colleagues face, we are disheartened that they will be taking strike action which will greatly inconvenience our passengers and local communities so close to the festive holiday period," he said.
Passengers have been urged to keep in touch with their airlines.