Airports across Europe have reopened after volcanic ash from Iceland caused flight disruption over the weekend.
Eurocontrol, the European air safety body, said the cloud of volcanic ash had now dispersed.
Lisbon airport in Portugal reopened on Monday morning at 0900 (0800 GMT), four hours earlier than expected.
However, Eurocontrol said flights were still being rerouted around clouds of ash being blown over the Atlantic Ocean, causing delays.
The agency said it expected some 28,500 flights within the European area on Monday, about 500 below the average for this time of year.
Portugal's civil aviation authority said airports on the Azores and Madeira islands remained closed.
As the weekend ended, some airspace closures were still in place over Iceland, as well as Portugal and the Atlantic.
In all, more than 300 flights were grounded over the weekend in Portugal, AFP news agency reported.
France and Austria were forced to ground some flights on Sunday night.
Spanish airspace began returning to normal on Sunday after 19 airports in the north of the country were closed on Saturday.
However, seven airports - Asturias, Santander, Bilbao, Salamanca, Valladolid, Leon and Burgos - were forced to close again from 1500 GMT on Sunday.
In Italy, airports at Milan, Pisa and Florence reopened after midday on Sunday, but disruption was widespread and there were delays for UK-bound flights.
And French authorities grounded at least 70 flights bound for southern Europe from airports in Paris, Lyon, and Nice.
In Scotland, airports in Inverness, Kirkwall, Wick, Benbecula and Stornoway were shut for a time, but UK air traffic control service Nats later said there were no airspace closures.
And the Irish Aviation Authority imposed restrictions on Donegal, Sligo and Knock airports in the west of the country on Sunday afternoon.
Last month, ash from the Eyjafjallajokull volcano shut down airspace across Europe for five days.
Recent images have shown activity in the volcano increasing and emitting ash up to 20,000ft (6,000m).
Passengers are urged to check details of their flights before travelling to the airport.
Source: BBC News