LONDON - Officials further extended no-fly restrictions over Europe Saturday as a vast, invisible plume of grit continued to billow out of an Icelandic volcano and drift across the continent.The flight ban seemed likely to disrupt world leaders' plans to attend Sunday's state funeral for Polish President Lech Kaczynski and his wife Maria in the southern city of Krakow.South Korean Prime Minister Chung Un-chan was the first to announce he was canceling his trip to Poland. An 11-member delegation led by Chung had planned to leave on Saturday, said Shin Bu-seop, an official of the prime minister's office.So far, US President Barack Obama, Russian President Dmitry Medvedev and German Chancellor Angela Merkel are still on the list of attendees. Kaczynski's family insisted Friday 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 agency said about 16,000 of Europe's usual 28,000 daily flights were canceled — twice as many as were canceled a day earlier.Early Saturday, British officials extended their closure of airspace until at least 7 p.m. (1800 GMT), and reintroduced the ban over Scotland and northern England. The Belgian government extended its ban until the same time.Italian aviation authorities were closing airspace in northern Italy on Saturday until midday (1000 GMT), with airports in Milan and Venice to close.Germany shut down all of its international airports, including Munich and Frankfurt, Europe's third-busiest terminal, until at least 2 p.m. (1200 GMT). National carrier Lufthansa said it was canceling all flights through 8 p.m. (1800GMT) Saturday.Australia's Qantas canceled all flights to Europe on Saturday, and passengers were being offered refunds or seats on the next available flight. The airline said it was not known when flights would resume. Cathay Pacific was already canceling some Europe-bound flights leaving Hong Kong on Sunday.Fears that microscopic particles of highly abrasive ash could endanger passengers by causing aircraft engines to fail have shut down air space at one time or another over much of Europe in recent days.On Friday, US 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 says the volcano is costing the industry at least $200 million a day.Southern Iceland's Eyjafjallajokull (ay-yah-FYAH'-plah-yer-kuh-duhl) volcano began erupting for the second time in a month on Wednesday, sending ash several kilometers 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 US 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 US 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 US military has also stopped using temporarily closed air bases in the UK and Germany.Aviation experts said it was among the worst disruptions Europe has ever seen.In Iceland, torrents of water carried away chunks of ice the size ofsmall houses on Thursday as hot gases melted the glacier over thevolcano. Sections of the country's main ring road were wiped out by theflash floods.More floods from melting waters are expected as long as the volcanokeeps erupting — and in 1821, the same volcano managed to erupt formore than a year.Small amounts of ash settled in northern Scotland and Norway, but officials said it posed little threat to health.Iceland, a nation of 320,000 people, sits on a large volcanic hot spotin the Atlantic's mid-oceanic ridge and has a history of devastatingeruptions. One of the worst was the 1783 eruption of the Laki volcano,which spewed a toxic cloud over Europe, killing tens of thousands.