BBC Weather's Liam Dutton tracks the ash cloud's journey east
UK air passengers are facing further disruption from a volcanic ash cloud that has affected European flights.
Portugal, France and Austria have all been forced to ground some flights overnight.
Italian airports which were closed have reopened but there are delays for UK-bound flights.
Meanwhile, jets in Britain due to fly to affected areas were grounded and the Met Office warned the ash may return to UK airspace in the coming days.
In Scotland, airports in Inverness, Kirkwall, Wick, Benbecula and Stornoway were shut for a time, but later reopened.
However Barra, in the Outer Hebrides, remains closed until at least 0100 BST on Monday.
Stewart Stevenson, Scotland's transport minister, said disruption had been "limited".
The Irish Aviation Authority imposed restrictions on Donegal, Sligo and Knock airports in the west of the country on Sunday afternoon. Airports in Dublin, Shannon and Cork were expected to stay open until at least 0100 BST on Monday.
Abta's Frances Tuke says volcanic ash is hitting air travel less than in April
Fulham manager Roy Hodgson has called on Uefa to postpone his side's Europa League final against Athletico Madrid in Hamburg if the volcanic ash causes more travel chaos ahead of Wednesday's clash.
Hodgson said getting the team of 40, including players and backroom staff, to Germany could turn into a logistical nightmare if airspace restrictions are still in force.
He said: "It could be very problematic and I only hope we have the luck to see the ash cloud disappear from the airspace between England and Germany."
Simon Calder, travel editor of the Independent, said that Glasgow had taken the place of Reykjavik as an international hub.
He added that some passengers travelling to North America were facing "horrendous delays" of up to 16 hours.
All flights to Porto in northern Portugal and the Azores were suspended, with normal operations expected to resume by 0700 BST on Monday, Portuguese airport officials said.
In all more than 200 flights were grounded in Portugal, including 71 at Lisbon's airport, where Pope Benedict XVI is due to arrive on Tuesday for a four-day visit to the country.
In Italy, airports at Milan, Pisa and Florence reopened after midday but disruption was widespread.
'Until further notice'
French authorities grounded at least 70 flights bound for southern Europe from airports in Paris, Lyon, and Nice, the nearest international airport to Cannes which is to host its world-famous film festival in three days' time.
The French weather service warned that volcanic ash could drift over southern France by Monday morning and that it could continue to affect Europe's skies for several months.
All flights were grounded at Munich airport in southern Germany on Sunday afternoon, with airports at Augsburg, Memmingen and Stuttgart also affected, Germany's DFS air safety agency said.
The measures would be in force "until further notice", the agency said.
Austrian authorities closed its airports gradually, starting with Innsbruck at 0230 BST through to Vienna which was due to shut down at midnight local time - 2300 BST.
The flight ban is expected to remain until 0400 BST on Monday.
The scene in the ash-covered Icelandic town of Vik
Spanish airspace had been returning to normal on Sunday after 19 airports in the north were closed on Saturday.
But the national air agency Aena announced that seven airports were again closing from 1600 BST - Asturias, Santander, Bilbao, Salamanca, Valladolid, Leon and Burgos.
Airports at Santiago de Compostela, Vigo and La Coruna were reopening at 1700 BST, it added.
Briton Lisa Thiel, 29, from Leeds, is stranded in Barcelona with her father Alan, 60, after the disruption affected their Easyjet flight.
The pair, who travelled to Spain to watch the Grand Prix, arrived at the airport at around 1830 BST to find the service was cancelled and they could get another flight home until Wednesday.
Miss Thiel, who estimated that about 450 people were also waiting in the airline's hall, said: "There was a very long queue at the Easyjet check-in desk, but there are staff helping to find hotels."
Poland's aviation authority kept its airspace open but was monitoring the situation carefully as the ash cloud gradually closed in on the country.
Volcanic activity rising
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).
The current wave of disruption could carry on into next week if northerly winds bring ash over western Scotland and Ireland.
Passengers are urged to check details of their flights before travelling to the airport.
Frances Tuke from Abta - which represents travel agents and tour operators - said the majority of airspace will be open and although some flights have been delayed, people were still able to fly.
Eurocontrol said that approximately 24,500 flights were expected to take place within Europe "which is about 500 below average for a Sunday at this time of year".
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