Bristow is among the helicopter firms to ground offshore flights
Hundreds of oil industry workers remain either stranded offshore or waiting for flights onshore, as the Iceland volcano ash continues to cause travel chaos.
All three North Sea helicopter operators - Bond, Bristow and CHC - grounded operations to and from North Sea oil and gas installations.
One worker waiting in Aberdeen for a flight said the delay was tedious, but those offshore would be keeping busy.
Bad weather can often cause travel problems for offshore workers.
Gordon Murray, 46, was spending his second day in Aberdeen on Friday, waiting for news of his flight to Shetland, and then offshore.
He told the BBC Scotland news website: "I am sitting reading the Illustrated History of Scotland, I found it in the hotel.
"I am just waiting on my company to tell me what's happening.
"We are flying to Shetland, but the restrictions could be different as it's nearer Iceland."
Mr Murray explained: "There are about 150 or 200 guys waiting for flights, and the same waiting to come back.
"It's a bit tedious. The guys on the rigs will just keep working, but some will be wanting home to their families.
"I have been stuck offshore many, many times before because of the weather, I think three days was the most."
Industry body Oil and Gas UK's health and safety director Robert Paterson said: "Workers always want to get home fairly quickly.
"But safety of the workforce and the helicopter crews remains paramount."
Most air travel will remain affected in Scotland and the rest of the UK until at least 1900 BST.
Particles of the volcanic ash, collected in Lerwick on Shetland, are being examined by the Scottish Environment Protection Agency.