Mist and fog at the weekend led to various flights to and from Sumburgh being either delayed or cancelled.
On Saturday the outbound flights to Glasgow and Kirkwall were cancelled, as was an inbound flight from Kirkwall. An inbound flight from Edinburgh diverted to Kirkwall and Flybe arranged for all 25 passengers to be put on the Saturday night boat from Kirkwall to Lerwick.
On Sunday an inbound Kirkwall flight and two from Aberdeen were cancelled, and one of the flights from Edinburgh turned back before arriving at Sumburgh. Outbound flights to Kirkwall, Edinburgh and two to Aberdeen were also cancelled, and flights which did manage to take off or land were subject to delays.
A spokesman said that volcanic ash had not played a part in the disruptions, and the airport was catching up with flights today.
Scatsta Airport was also badly affected at the weekend. Almost all of the helicopter flights were cancelled as the east Shetland basin was shrouded in fog, and many fixed wing flights were also cancelled as there was fog at the destination airports.
A spokesman said Scatsta already had a backlog of passengers waiting to fly after volcanic ash had affected flights earlier in the week. Flying only took place at the weekend when it was deemed safe, he said, and the situation changed from hour to hour. The backlog was eventually cleared.
Scatsta normally operates 18 helicopter and 12 fixed wing flights per day.