Flights from all UK airports were cancelled from midday GMT today due to a volcanic eruption in Iceland. Passengers were left stranded at the terminals with services not set to return to normal until at least 7am Friday morning.
Airports in southern England, including Heathrow and Gatwick, had tried to remain open, but they were also forced to close as the ash cloud moved further south.
Airspace in Sweden and northern Finland was also closed and airports in southern Finland, Denmark and Norway cancelled a substantial number of flights.
Danish airspace was set to close completely at 4pm and Finland said it is unlikely to reopen until at least midday on Friday.
All flights from Belgium were cancelled from 2.30pm, while the Netherlands is progressively closing its airspace.
France has already announced that flights are likely to be cancelled, although there were no plans to ground all flights. Germany is currently monitoring the situation, although the knock-on effect of the cancelled flights elsewhere are yet to be known.
Rail companies and ferry operators are reporting increased numbers of passengers as travellers seek alternative routes for breaks this weekend.
According to safety body Eurocontrol, up to 4,000 flights in the region were likely to be affected.
Air traffic control in the UK has said that the situation is unlikely to improve in the foreseeable future.