Shetland and Orkney's airports are closed to flights today as air traffic controllers stage the second of three 24-hour strikes over pay.
Prospect union members have resumed industrial action after rejecting a revised pay deal from Highlands and Islands Airports Limited (Hial).
Six airports are affected by the action as union members stage 24-hour strikes between Sunday and Tuesday.
READ MORE: Nurse wanted for idyllic Scottish island as Raasay seeks to boost its medical cover
Sumburgh Airport in Shetland and Kirkwall Airport in Orkney are shut today, while Inverness Airport was closed on Sunday.
On Tuesday, Stornoway, Benbecula and Dundee Airports will be closed.
Hial said the offer rejected by air traffic controllers comprised a retention allowance which would have seen them benefit from an additional £10,000 over a five-year period.
Managing director Inglis Lyon said previously that he "deeply regrets the inconvenience and upset to hundreds of passengers affected by the strike action".
He called on Prospect to resume talks to find a resolution to the dispute as soon as possible and claimed the union is asking for a pay increase "far in excess of what we are able to afford".
READ MORE: Bid to prevent 'leaves on the line' rail delays
Air traffic controllers previously went on strike on May 23, when six airports were shut for 24 hours due to the industrial action.
Prospect national secretary Richard Hardy said the strikes are a "last resort".
"Hial and Scottish ministers have left our members with no option but to strike," he said previously.
"Strike action is by its nature disruptive but if we are to safeguard the long-term future of air services in the Highlands and Islands we have to start paying air traffic controllers a fair wage."
READ MORE: British Airways continues to suspend flights to Cairo over security fears
Hial is a public corporation wholly owned by the Scottish ministers.
A Scottish Government spokesman has said the Government encourages both parties to resolve the dispute as it is "clearly not in the interest of passengers or the communities served by Hial airports".
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here