Flights to and from Ireland and Scotland faced fresh disruption on Wednesday because of a cloud of abrasive volcanic ash drifting south from a volcano erupting in Iceland.
Two airports serving Glasgow, Scotland's largest city, were expected to be closed until 1800 GMT, while flights from the Irish capital Dublin faced restrictions from 1000 GMT.
The latest disruption, which could signal that travel disruption will continue into the summer holiday period, was caused by ash being blown from the same volcano in Iceland that caused mayhem for 10 million travellers last month.
British Airways said it was cancelling all flights to and from the Scottish cities of Glasgow, Edinburgh and Aberdeen until 1200 GMT.
Irish budget airline Ryanair also cancelled flights to Edinburgh, Glasgow Prestwick and the northern Irish cities of Belfast and Derry until Wednesday afternoon.
Airports in Ireland and parts of Britain were shut for a number of hours on Tuesday.
Britain's Civil Aviation Authority said airports in northern England could also be affected, but did not anticipate problems in the southeast, where the major airports serving London are located.
AIRLINES UNDER A CLOUD
Much of European air traffic was grounded last month because of the spread of ash from an erupting volcano under the Eyjafjallajokull glacier in Iceland. Some 100,000 flights were cancelled and millions of passengers stranded.
AIRLINES UNDER A CLOUD
Much of European air traffic was grounded last month because of the spread of ash from an erupting volcano under the Eyjafjallajokull glacier in Iceland. Some 100,000 flights were cancelled and millions of passengers stranded.
Tuesday was the first test of a European system of progressive closures, including partial no-fly zones, introduced after the abrasive ash cloud prompted a blanket ban that was criticised by airlines forced to ground thousands of flights in
April.
European transport ministers have agreed to set safety limits for flying through the ash, which can paralyse jet engines, and to unify European airspace.
Last month's airspace closures cost Europe's airlines 1.5 billion to 2.5 billion euros ($2 billion-$3.3 billion), the European Commission has estimated.