|Millions of people have been affected by flight cancellations in Europe and across the world [AFP]
List of countries across Europe with flight disruptions due to the volcanic ash cloud as of 9:00 GMT on Wednesday:
Austria - Austria reopened its airspace on Monday but some flights remain cancelled.
Australia - Qantas will continue to cancel its flights to Europe until at least the end of Wednesday.
Belgium - Flight restrictions were partially lifted from 06:00 GMT on Tuesday.
Bosnia - Airports open.
Britain - All UK airspace reopened at 21:00 GMT on Tuesday.
Bulgaria - All airspace and airports open.
Czech Republic - Air space reopened on Monday. Prague airport has confirmed two-thirds of normal daily flights for Tuesday.
Croatia - Airspace and all airports open. Croatia Airlines, the national carrier, restored all domestic and international flights on Tuesday.
Denmark - All airspace to open at 9:00 GMT Wednesday.
Estonia - Airspace reopened at 20:00 GMT on Tuesday.
Finland - Airspace open until further notice, and most airports to be in operation by 09:00 GMT on Wednesday.
France - The two main airports in Paris, Roissy and Orly, opened from 06:00 GMT on Tuesday to allow a limited number of flights. Most French airports now open to limited traffic. Air France plans to run all long-haul flights on Wednesday, but some flights to northern Europe remain suspended.
Germany - Airspace gradually reopening on Wednesday, to be fully
reopened from 9:00 GMT.
Hungary - Airspace open since Monday, with minor restrictions overnight. About 15 flights departed early Tuesday.
Iceland - Air space open but many flights to Europe cancelled.
Ireland - Airspace reopened.
Italy - Airspace reopened.
Latvia - Airspace reopened at 06:00 GMT on Tuesday.
Lithuania - Airspace is open. There have been departures from Vilnius International Airport. But all flights at Kaunas airport have been cancelled.
Luxembourg - Luxembourg Airport reopened at 08:00 GMT on Tuesday.
Moldova - Resumed international flights from 07:30 GMT.
Montenegro - Airports open.
Netherlands - Passenger flights began on Monday. Night flights resumed on Tuesday.
Norway - Aviation officials opened Norwegian airspace on Tuesday afternoon until at least 12:00 GMT on Wednesday.
Poland - Polish Air Navigation Services said airspace will be open at 05:00 GMT Wednesday.
Romania - Airspace reopened on Monday at 18:00 GMT with all airports operating.
Russia - All airports open. Aeroflot flying to the United States via the North Pole.
Serbia - Airports open.
Slovakia - Reopened its airspace on Monday at 12:30 GMT, but Ryanair cancelled all Tuesday flights from Bratislava.
Slovenia - Airspace reopened at 10:00 GMT on Tuesday.
Spain - Reopened all airports on Sunday.
Sweden - Most airports open. Airports in Stockholm and Gothenburg to open at 13:00 GMT on Wednesday.
Switzerland - Reopened as scheduled at 06:00 GMT on Tuesday but some flights were cancelled at Geneva and Zurich airports.
Turkey - All airports open. Planes flying out of the Black Sea cities of Samsun, Sinop and Zonguldak have been advised not to fly higher than 6,000 metres.
Ukraine - Kiev's Borispol international airport open.