There are currently no closures of airspace or airports within the European area, and a normal number of 28,500 flights are expected Thursday, say aviation authorities.
Airspace in the Ireland and the north of Britain has been intermittently closed during the week due to volcanic ash, but weather fronts have now pushed the ash out towards the Atlantic, some 100 to 200 miles (161 km - 322 km) west of Ireland.
Approximately 400 flights were cancelled in Scotland and Ireland, said European air traffic control body Eurocontrol.
Current forecasts for Thursday night and Friday morning local time predict that the ash will move further southwards but remain across the Atlantic.
Observers have said that the activity of the Eyjafjallajokull volcano in Iceland increased overnight between May 5 to 6, resulting in more intensive ash eruptions and a dispersal of ash at higher altitudes.
Air authorities are now in discussions about rerouting transatlantic flights to ensure that the cloud is avoided.
Irish Aviation Authority http://www.iaa.ie
National Air Traffic Services http://www.nats.co.uk/
Met Office Volcanic Ash Advisory Centres http://www.metoffice.gov.uk/aviation/vaac/