LONDON — The miasma of volcanic ash hovering over Europe showed no sign of dissipating yesterday, keeping thousands of forlorn travelers stranded across the continent for a third day and worsening economic losses.

The cloud of grit from the still-erupting Eyjafjallajokull (ay-yah-FYAH'-plah-yer-kuh-duhl) volcano in Iceland began creeping as far south as Italy, prompting shutdown of airports in the northern part of the country.

Travelers continued their scramble for hotels, or for trains, ferries and even taxis to reach their destinations. In Copenhagen, an enterprising cab company posted fares for long hauls across the continent: about $2,000 for passengers going to Amsterdam; $6,000 all the way to Madrid.

Activity in the volcano increased early yesterday, and showed no sign of abating.

"There doesn't seem to be an end in sight," Icelandic geologist Magnus Tumi Gudmundsson said yesterday. "The activity has been quite vigorous overnight, causing the eruption column to grow."

Scientists say that because the volcano is below a glacial ice cap, the magma is being cooled so quickly that it explodes and creates plumes of grit that, carried on prevailing winds, can be catastrophic to plane engines.

Most of British airspace remained closed, with planes grounded until this afternoon at the earliest, despite a brief window of opportunity for a few flights yesterday afternoon from airports in Scotland, Northern Ireland and northern England.

By last night, the volcanic pall covered the whole country once again.

In Germany and northern France, including Paris, authorities canceled all flights until early today. Irish, Belgian, Dutch, Austrian and Swiss airspace was restricted. Most major airports throughout Scandinavia were idled, including Arlanda, Stockholm's largest.

With the pileup of marooned passengers growing by the hour, and with U.S. airlines canceling more than 80 percent of their flights to Europe yesterday, analysts say clearing out the backlog and getting the system back to normal could take days once the ash cloud dissipates. No one was predicting when that will happen.

"It's still erupting," Hoskuldsson said of the volcano. "It's more or less constant."

ECONOMIC DAMAGE

As winds blew the volcanic debris farther south and east, previously unaffected countries in central and eastern Europe — as far away as Ukraine — also began halting air traffic.

The disruptions threw into further doubt the plans of world leaders to attend today's state funeral in Krakow for Polish President Lech Kaczynski, who was killed in a plane crash a week ago. President Obama yesterday canceled his plans to go.

"I spoke with acting President (Bronislaw) Komorowski, and told him that I regret that I will not be able to make it to Poland due to the volcanic ash that is disrupting air travel over Europe," Obama said in a statement issued by the White House.

Other guests, including high-level delegations from Spain and South Korea, had already sent their regrets.

Trade and tourism losses mounted in a region already struggling to get out from under the thumb of the global recession.

Perishable foods marked for export sat untouched in warehouses, while roses and other fresh flowers from as far away as Africa and Asia were in danger of wilting and dying before reaching European markets.

In Britain, there were reports of shortages of a few items on supermarket shelves, including certain fruits. The country imports much of its fruits and vegetables, most arriving by sea but some flown in.

The aviation industry is facing at least $200 million in losses every day, according to the International Air Transport Association. The Europe-wide aviation agency Eurocontrol said it expected only 5,000 flights across European airspace yesterday, compared with 22,000 normally.

Scandinavian airline operator SAS AB said it has given notice of a temporary layoff of up to 2,500 ground service staff in Norway as a result of the flight disruptions.

Budget airline Norwegian ASA, losing $1.5 million to $1.7 million a day because of the ash-driven closures, will meet with unions tomorrow to discuss potential temporary layoffs, spokeswoman Asta Braathen said.

'IT'S A REAL INFERNO'

Forecasters say light prevailing winds in Europe — and large amounts of unmelted glacial ice above the volcano — mean that the situation is unlikely to change quickly.

"Currently the U.K. and much of Europe is under the influence of high pressure, which means winds are relatively light and the dispersal of the cloud is slow," said Graeme Leitch, a meteorologist at Britain's National Weather Service. "We don't expect a great deal of change over the next few days."

A Dutch geologist who is in Iceland observing the volcano, Edwin Zanen, described it to Dutch state broadcaster NOS:

"We're at 25 kilometers (16 miles) distance from the crater now. We're looking at a sun-soaked ice shelf, and above it is looming a cloud of ashes of, oh, 4 to 5 kilometers (2 1/4 to 3 miles) high. There are lightning flashes in it.

"There's absolutely no sign that the thing is calming down. On the contrary, we can see that at this moment it's extraordinarily active," he said.

A team of volcanologists from the University of Iceland had to call off yesterday's planned flight over Eyjafjallajokull intended to glean more information on how much longer the ash might continue spewing.

UP IN THE AIR

With the prospect of more days under the cloud of ash, pilots and aviation officials sought to dodge the dangerous grit by adjusting altitude levels.

Germany's airspace ban allows for low-level flights to go ahead under visual flight rules, in which pilots don't rely on their instruments.

Lufthansa took advantage of that to fly 10 empty planes to Frankfurt from Munich yesterday to have them in the right place when the restrictions are lifted, airline spokesman Wolfgang Weber said.

The planes flew at about 9,843 feet — well below their usual altitude — in close coordination with air traffic control.

KLM is test-flying from Schiphol to Dusseldorf at 9,843 feet or lower, hoping for approval for more low-altitude flights in Europe if the ash problem continues.

The Swiss looked in the other direction — above the ash cloud. The Swiss Federal Office of Civil Aviation began allowing flights yesterday above Swiss air space as long as the aircraft were at least at 36,000 feet. It also allowed flights at lower altitudes under visual flight rules, for small, private aircraft.