A lingering volcanic ash plume forced extended no-fly restrictions over much of Europe on Saturday, as Icelandic scientists warned that volcanic activity had increased and showed no sign of abating - a portent of more travel chaos to come.
Scientists say that because the volcano is situated below a glacial ice cap, the magma is being cooled quickly, causing explosions and plumes of grit that can be catastrophic to plane engines if prevailing winds are right.
"The activity has been quite vigorous overnight, causing the eruption column to grow," Icelandic geologist Magnus Tumi Gudmundsson told The Associated Press on Saturday.
"It's the magma mixing with the water that creates the explosivity. Unfortunately, there doesn't seem to be an end in sight."
An expansive cloud of grit hovered over parts of western Europe on Saturday, triggering extended flight bans that stranded people around the globe. Continued volcanic activity could produce more plumes if the weather patterns stay the same.
The Icelandic Meteorological Office said the amount of ash in the plume grew Saturday and that the vast ash cloud is continuing to travel south and southeast.
Scientists had planned to fly over the volcano to see how much ice has melted to determine how much longer the eruption could spew ash, but the Icelandic Coast Guard said Saturday's flight had been postponed.
Aviation experts say the volcanic plume has caused the worst travel disruption Europe - and the world - has ever seen.
"I've been flying for 40 years but I've never seen anything like this in Europe," said Swedish pilot Axel Alegren, after landing his flight from Kabul, Afghanistan, at Munich Airport; he had been due to land at Frankfurt but was diverted.
Anxious passengers have told stories of missed weddings, graduations, school and holidays because of the ominous plume, which 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.
So far, delegations from India, Japan, South Korea, Mexico, New Zealand and Pakistan have canceled plans to attend the state funeral.
President Barack Obama, Russian President Dmitry Medvedev and German Chancellor Angela Merkel still planned to attend.
On Saturday, the French prime minister extended the closure of airspace in northern France until Monday morning.
British and German airspace is closed until at least 0000 GMT Sunday (8 pm EDT Saturday), and British Airways is canceling all short-haul flights to and from London airports Sunday. The Belgian, French and Swiss governments extended their ban until Saturday evening.
Stranded passengers reported the delays were causing financial hardships. Some had to check out of hotels and sleep in the airports.
"I have been staying in a hotel but have now checked out and do not know what I am going to do - I have limited financial resources here," said Anthony Adeayo, 45, who was due to travel from Britain to Nigeria with British Airways.
Eva Macieyow, 33, said she had been due to depart for Germany with a friend.
"We are a little frustrated," she said.
"Last night we thought we had a flight ... but now it has been canceled and we know nothing."
Shoppers were warned Saturday that continued flight bans could spark shortages of imported fresh fruit and vegetables.
"There are no shortages yet, but we may start to see certain ranges affected if this carries on," said Christopher Snelling, head of global supply chain policy for the Freight Transport Association.
Italian aviation authorities were closing airspace in northern Italy on Saturday until midday (1000 GMT; 6 am EDT), with airports in Milan and Venice to close. Spain's Iberia airline is canceling most of its European flights until further notice.
Denmark and Finland's airspace also remained closed, while Norway and Sweden said some air space in the far north could be opened as the cloud moves south. Air space in the central and southern parts of the Nordics was expected to remain closed at least until Sunday afternoon.
Serbia also closed a small strip of its airspace in the north of the country and said it could close more later. Belarus and Ukraine introduced closures and restrictions.
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.
"The British Airways telephone message says check the Web site for updates but when you check the site it says call the customer services number," said James Kirkman, 41, who was visiting family in Australia with his two kids.
"There's no information. The kids were due back at school on Monday."
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 miles (kilometers) into the air. Winds pushed the plume south and east across Britain, Ireland, Scandinavia and into the heart of Europe.
Authorities told people in the area with respiratory problems to stay indoors, and advised everyone to wear masks and protective goggles outside.
The air traffic agency Eurocontrol said about 16,000 of Europe's usual 28,000 daily flights were canceled on 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 says the volcano is costing the industry at least $200 million a day. 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. In Iceland, torrents of water have carried away chunks of ice the size of small houses. Sections of the country's main ring road were wiped out by the flash floods.
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.
Iceland, a nation of 320,000 people, sits on a large volcanic hot spot in the Atlantic's mid-oceanic ridge and has a history of devastating eruptions. One of the worst was the 1783 eruption of the Laki volcano, which spewed a toxic cloud over Europe, killing tens of thousands.