LONDON — Thick drifts of volcanic ash blanketed parts of rural Iceland on Friday as a vast, invisible plume of grit drifted over Europe, emptying the skies of planes and sending hundreds of thousands in search of hotel rooms, train tickets or rental cars.
Polish officials worried that the ash cloud could threaten the arrival of world leaders for Sunday's state funeral for President Lech Kaczynski and his wife Maria in the southern city of Krakow.
So far, President Obama, Russian President Dmitry Medvedev and German Chancellor Angela Merkel are among those coming and no one has canceled. Kaczynski's family insisted Friday that they wanted the funeral to go forward as planned but there was no denying the ash cloud was moving south and east.
The air traffic agency Eurocontrol said almost two-thirds of Europe's flights were canceled Friday, as air space remained largely closed in Britain and across large chunks of north and central Europe.
"The skies are totally empty over northern Europe," said Brian Flynn, deputy head of Eurocontrol, adding "there will be some significant disruption of European air traffic tomorrow."
The agency said about 16,000 of Europe's usual 28,000 daily flights were canceled Friday — twice as many as were canceled a day earlier.
U.S. airlines canceled 280 of the more than 330 trans-Atlantic flights of a normal day, and about 60 flights between Asia and Europe were canceled.
The International Air Transport Association said the volcano was costing the industry at least $200 million a day.
Southern Iceland's Eyjafjallajokull glacier began erupting for the second time in a month on Wednesday, sending ash several miles into the air. Winds pushed the plume south and east across Britain, Ireland, Scandinavia and into the heart of Europe.
Gray ash settled in drifts near the glacier, swirling in the air and turning day into night. Authorities told people in the area with respiratory problems to stay indoors, and advised everyone to wear masks and protective goggles outside.
In major European cities, travel chaos reigned. Extra trains were put on in Amsterdam and lines to buy train tickets were so long that the rail company handed out free coffee.
Train operator Eurostar said it was carrying almost 50,000 passengers between London, Paris and Brussels. Thalys, a high-speed venture of the French, Belgian and German rail companies, was allowing passengers to buy tickets even if trains were fully booked.
Ferry operators in Britain received a flurry of bookings from people desperate to cross the English Channel to France, while London taxi company Addison Lee said it had received requests for journeys to cities as far away as Paris, Milan, Amsterdam and Zurich.
The disruptions hit tourists, business travelers and dignitaries alike.
German Chancellor Angela Merkel had to go to Portugal rather than Berlin as she flew home from a U.S. visit. Norwegian Prime Minister Jens Stoltenberg managed to get a flight to Madrid from New York but was still not sure when or how he would get back home.
The military also had to adjust. Five German soldiers wounded in Afghanistan were diverted to Turkey instead of Germany, while U.S. medical evacuations for troops in Iraq and Afghanistan are being flown directly from the warfronts to Washington rather than to a care facility in Germany. The U.S. military has also stopped using temporarily closed air bases in the U.K. and Germany.
Aviation experts said it was among the worst disruptions Europe has ever seen.
"We don't have many volcanoes in Europe," said David Learmount of Flight International, an aviation publication. "The wind was blowing in the wrong direction."
In Iceland, more floods from melting waters are expected as long as the volcano keeps erupting — and in 1821, the same volcano managed to erupt for more than a year.