Strong winds whipping in from the North Sea should disperse the volcanic ash cloud that has caused many UK flights to be cancelled this week, but it looks certain to delay more air passengers before it swirls into the Atlantic, forecasters said last night.

The Met Office said north-westerly winds would sweep the ash cloud from the western fringes of the UK today, after passengers suffered another day of confusion and disruption.

Airspace above Scotland, Northern Ireland and the Republic of Ireland was closed yesterday, and services were grounded at Glasgow, Edinburgh, Belfast, Dublin and Derry.

Most Irish airspace was scheduled to reopen at 4am this morning, though some western airports were to remain closed until 9am.

Some passengers were unaware that airports were operating until 1pm, and missed their flights. Scotland's First Minister, Alex Salmond, complained that the Civil Aviation Authority (CAA) had issued a "vague" statement on Tuesday night that suggested that all Scottish airspace would be closed because of the return of the ash cloud.

Edinburgh and Aberdeen airports, along with the two airports in Belfast, were, in fact, open for the first part of the day. "Unnecessarily, some flights were cancelled, particularly into Edinburgh, because of the vagueness of the press release they [the CAA] put out," Mr Salmond said.

"That can't be allowed to happen again. It's really, really important, where there are difficult messages, that press statements must be clear and not cause confusion." He said the CAA, which warned that the situation remained "changeable", had since apologised.

As uncertainty over the ash cloud's progress continued, the CAA advised passengers due to travel from most parts of the UK – including Scotland, Wales, Northern Ireland, and the South-west and North of England – to contact airlines to check whether their flight was operating. "Based on current forecasts, we do not expect airports in the South-east of England to be affected," the CAA said.

The Met Office spokesman John Hammond said: "The current suggestions are that the cloud will begin to ease over Scotland and will be lifted over Northern Ireland and Wales [today]. Winds will blow in from the North Sea and other parts of Europe, effectively cutting off the supply of ash coming down from Iceland and pushing it out over the water."

Clearing the cloud will allow airlines to reschedule dozens of services that have left passengers stranded – but this may come too late for some. Mabel McGeachie, 62, from East Kilbride, Scotland, whose easyJet flight from Glasgow to Malaga in Spain was cancelled yesterday, had been travelling with 10 friends and relatives for her daughter's hen night. She was told the next available flight would be on Sunday – the day she was meant to return.

"We are feeling disappointed as we were looking forward to it and I don't think we'll be able to rearrange it. It was my daughter's hen do and her wedding is in July," she said. "We heard about the ash last night but just came down to the airport anyway."

Scottish football club Ross County cancelled plans to fly from Glasgow to Marbella in Spain to train ahead of their Scottish FA Cup final against Dundee United on 15 May. Ross's director of football George Adams was philosophical about missing out on the trip, saying the team was disappointed but practical. "Lots of people have been disrupted with the volcanic ash and we're no different from anyone else," he said.

Ryanair, BMI, Aer Lingus and Flybe were among the airlines that had to cancel services, with Flybe's cancellations including some flights from Manchester, Liverpool, Luton and Cardiff.

Ash from the erupting Eyjafjallajokull volcano in Iceland caused a total shutdown of UK airspace for five days last month, the most severe action in northern Europe. The problem is estimated to have delayed 10 million passengers and cost the aviation industry up to £2.1bn.