Irish airspace should remain open until at least 7.30pm this evening.
The Irish Aviation Authority has said that it does not expect any restrictions because of the Icelandic ash cloud between now and then.
Aer Lingus intends to run full schedules after being forced to cancel a number of flights to Scotland yesterday.
Germany is among the worst affected countries today - dozens of flights, including a number on Ryanair's schedule, have been cancelled there already.
In Britain, frustrated travellers were hoping for a reprieve as the cloud was expected to have moved out of UK airspace.
The volcanic ash, a result of the recent eruption of Grimsvotn in Iceland, was predicted to have cleared by 1am, according to UK air traffic control company Nats.
Dozens of flights to and from Scotland and Newcastle were cancelled yesterday, with around 500 halted across Europe, but UK Transport Secretary Philip Hammond held out hope that the worst was over for air passengers.
However, officials in Germany said dozens of flights would be grounded in the country today, with take-offs and landings cancelled at the northern Bremen and Hamburg airports as a result of increased levels of ash in the atmosphere.
Domestic and international flights were to be affected by the closure, and authorities said it may be necessary to halt all air traffic coming and going from Berlin’s airports, as well as Hannover, depending on the winds.
Earlier, Ryanair warned customers travelling to or from Bremen, Lubeck and Magdeburg airports that their travel could be disrupted.
In its most recent update, a statement on the Nats website read: “Latest information from the Met Office shows that following the recent eruption of Grimsvotn in Iceland, no volcanic ash is currently predicted in airspace over the UK from 0100 UK time on Wednesday May 25.”
But the company advised passengers to continue checking airline updates before travelling.
A Met Office spokesman said the ash was likely to clear northern parts of the UK by early today.
Despite the better volcanic and weather forecast, the Barcelona football team, due to take on Manchester United at Wembley in the Champions League final on Saturday, brought forward their journey to London from Thursday to yesterday.
After chairing a meeting of Cobra, the British Government’s emergency planning committee, Mr Hammond said the volcanic ash plume was getting smaller and less intense.
He added that south-westerly winds were likely to take the ash away from the UK and that he was “cautiously optimistic” that disruption would be kept to a minimum from now on.
Mr Hammond also revealed that a special aircraft had been bought to test the intensity of ash levels but that the plane would not be operational until next month or early July.
He explained that flights were able to operate with levels of ash 20 times greater than permitted during last year’s Icelandic ash cloud crisis.
He also described as “irresponsible” remarks by Ryanair chief executive Michael O’Leary following the Irish carrier’s decision to send a test plane up into Scottish airspace to test ash levels.
Mr O’Leary said the plane had not encountered any ash and that the Civil Aviation Authority should allow flights in Scotland.
But Mr Hammond said that the Ryanair test flight had not passed through any high-density ash areas.
Meanwhile, British Airways sent a plane to test the ash.
An Airbus A320 left from Manchester airport to fly toward Newcastle and then over Glasgow and Edinburgh before heading south.
The plane, and its flight performance, was to be inspected by engineers upon its arrival at Heathrow.