All flights to and from Scotland's airports have been grounded as a plume of volcanic ash drifts across much of northern Europe.
Dust from the eruption in Iceland presents a serious risk to aircraft.
All Scottish airports have been closed although search and rescue helicopters are still able to fly.
Passengers are advised not to travel to airports. All flights in UK airspace have been suspended and disruption is expected to continue into Friday.
A BAA spokeswoman said: "Following advice from the Met Office, the National Air Traffic Service (Nats) has introduced restrictions to UK airspace this morning as a result of volcanic ash drifting across the United Kingdom from Iceland."Passengers intending to fly today are asked to contact their airline for further information and should expect disruption in the coming hours."
Airlines also issued warnings of potential disruption.
An EasyJet spokeswoman said: "Following the eruption of a volcano in Iceland yesterday, an ash plume has entered UK and Scandinavian airspace overnight.
"As a result Nats have closed parts of UK airspace and this is causing significant disruption to all airlines due to operate flights to and from the UK today."
The eruption under a glacier in the Eyjafjallajoekull area of Iceland is the second in Iceland in less than a month.
Residents in Shetland and Aberdeen have reported smelling the effects of the ash, describing it as "sulphurous".
Forecasters believe it could take a number of days to disperse.
Philip Avery from the Met Office said: "Nats has good cause to be very cautious about this because in about 1982 a British Airways jumbo had the unnerving experience of having all four engines shut down as it flew through a plume of volcanic ash."
Christine Campbell, 55, from Garelochhead, Argyll, who works at Faslane naval base, got to Glasgow Airport at 0530 BST for a flight at 0645 BST.
She was travelling with her daughter to La Rochelle in France for her son's wedding.
She said: "I'm really disappointed and upset because I've been looking forward to this wedding for two years and at the last minute there's this hiccup."
She said she was planning to try to get a train to London and then travel to France by Eurostar.
Another passenger said: "I'm meant to be going to Lanzarote. We've travelled from Oban, leaving at 3am. Now we've decided we might as well just go home and do a bit of gardening."
Glasgow Airport managing director Amanda McMillan said the financial impact on the Scottish air industry could run into "hundreds of thousands" of pounds.
The airport usually sees more than 15,000 passengers pass through on 200 flights a day.
Ms McMillan added: "There are a lot of people here who have worked here for many years but this is not something that anyone at the airport has seen before."
Glasgow Prestwick Airport in Ayrshire was also closed until further notice.
Aberdeen Airport spokeswoman Sarah Campbell said there were more journalists and staff there than passengers.
Aviation expert Jim Ferguson said: "Volcanic ash and aeroplanes do not mix.
"There was at least one British Airways 747 that turned itself into the world's biggest glider when it picked up a lot of ash over Indonesia and Indonesia had not notified anyone of the problem.
"The crew were able to eventually land the aircraft safely but there was an awful lot of people in the aviation industry thought they were headed for the water."
A Nats spokesman said: "The Volcanic Ash Advisory Centre has issued a forecast that the ash cloud from the volcanic eruption in Iceland will track over Europe tonight.
"Nats is working with Eurocontrol and our colleagues in Europe's other air navigation service providers to take the appropriate action to ensure safety in accordance with international aviation policy."
The Ministry of Defence said it was assessing what effect the dust will have on Exercise Joint Warrior - Europe's largest military training exercise which started on Monday.
Large numbers of the Nato aircraft and crews taking part were flying from RAF stations at Kinloss and Lossiemouth.
Elements of the training takes place around Cape Wrath in the north of Scotland.
Meanwhile, the disruption caused by the ash has caused a significant upturn in demand for rail services.
ScotRail, which operates 95% of services within Scotland plus the overnight Caledonian Sleepers, said there had been a "surge in demand".
A spokeswoman said: "Our telesales department, which also sells tickets for other train operators, has seen a near 300% increase in calls.
"The surge in demand is mostly for travel today to England from people whose UK domestic flights have been cancelled and are switching to rail.
"There have been queues at travel centres as people buy tickets to travel to London in particular.
"Demand for our overnight Sleeper services is massive, with this evening's northbound services virtually fully booked and only a handful of seats left southbound."
Published: 2010/04/15 12:07:04 GMT
© BBC MMX
Source link: http://news.bbc.co.uk/1/hi/scotland/8621444.stm
This is, from my geeky perspective, awesome. The cloud is at a high altitude so it's not really bothering us, but I've heard people in Aberdeen and Shetland saying they've had a really strong smell of sulphur hanging around all day. We're expecting some gorgeous, strange sunsets tonight. I'm travelling back to Glasgow from Fife today, and reckon I'll have a hard time getting a bus or train seat booked. It might go on through the weekend; at least the combo of an ash cloud and no planes is good for the environment, eh?
People looking for flight details have managed to crash the NATS website, and Alex Salmond and other Scottish Government ministers are having an emergency meeting.
ETA: We have a beautiful, weirdly blood red sunset up here now. It's fantastic.