Ash spewing from an Icelandic volcano is bringing disruption and days of uncertainty to more parts of Europe, as officials in Germany said dozens of flights will be grounded on Wednesday.
Even though some say it's been a massive overreaction by badly prepared safety regulators _ one airline even claims the official scientific findings are simply wrong _ hundreds of flights were canceled Tuesday as winds blew the cloud of ash from the Grimsvotn volcano over Scotland and other parts of Europe. Experts say that particles in the ash could stall jet engines and sandblast planes' windows.
The only comfort for frustrated passengers and airlines is that officials in Iceland said the amount of ash being released by the volcano is decreasing, and officials don't expect the disruption to be as bad as last year, when millions were stranded after the eruption of Iceland's Eyjafjallajokull volcano.
Travelers trying to go to or leave Scotland have been hit hardest, but the problem also began to affect Germany, where weather officials said it would not allow any takeoffs or landings at the northern Bremen and Hamburg airports early Wednesday due to increased levels of ash in the atmosphere.
Dozens of domestic and international flights were to be affected by the closure early Wednesday. Authorities said it may be necessary to halt all air traffic coming and going from Berlin's airports, as well as Hannover, depending on the winds.
In Sweden, 10 domestic flights were canceled Tuesday evening. The country's aviation officials say they expect medium concentrations of ash over its western coast late Tuesday, including over its second-largest city Goteborg.
Although British authorities said concentrations of ash in the skies over Scotland were too high to fly through, Irish budget airline Ryanair challenged the results, saying it had sent its own airplane into Scottish airspace and found no ash in the atmosphere.
"All the data we are receiving confirms our forecasts, that there is high-density ash over Scotland," said Barry Grommett, spokesman for Britain's weather agency.
Ryanair's chief executive Michael O'Leary disagreed.
"Exactly as we predicted, we encountered absolutely no problems," he told The Associated Press. "There's no cloud over Scotland. There's no dusting of ash on the airframe or the wings. The airspace over Scotland should never have been restricted in the first place."
Still, Ryanair was forced by Irish authorities to cancel all 68 flights in and out of Scotland for the rest of Tuesday. Seven other airlines _ most of them regional carriers _ also grounded their Scottish flights.
In Edinburgh, meanwhile, several hundred passengers faced either a patient wait or overnight stays in the city.
"I've been told I'll get home tomorrow, but who knows," said Kgeld Westh, an architect from Copenhagen. He was heading to a hotel in Edinburgh after his flight was canceled.
Among the crowds at the airport were soccer fans heading to Dublin for the international match between Scotland and Ireland.
"If all else fails we'll make our way by train and ferry," said Gary Clark, from Hamilton near Glasgow wearing a kilt and a Scotland shirt.
The main international body representing carriers, the International Air Transport Association, complained to the British government about the way it had handled the issue, saying it should have had Cessna planes ready to carry out tests, instead of relying on the weather service. British Airways said it sent its own verification flight, an Airbus A320, to Scotland late Tuesday to assess the risk.
The Grimsvotn volcano began erupting on Saturday, sending clouds of ash high into the air. The amount of ash spewing from the volcano tapered off dramatically on Tuesday, however, said Elin Jonasdottir, a forecaster at Iceland's meteorological office. She added that because the plume has decreased in height _ it's now at about 5,000 meters (16,000 feet) _ the ash won't travel far and will most likely fall to the ground near its source.
U.K. air traffic control company NATS said that the ash cloud is expected to clear British airspace early Wednesday. Earlier there were fears that the ash cloud might also affect France, but French civil aviation authority DGAC on Tuesday sounded an optimistic note.
"Forecasts for the next few days are promising, French airspace should be affected only very marginally by the volcanic ash," it said in a statement. "No closure of French airspace is currently envisioned."
U.K. airspace was not closed, but some airlines would rather not take risks and were willing to follow official advice. EasyJet had 113 cancelations Tuesday in and out of Scotland, Newcastle and Northern Ireland. British Airways grounded 92 flights in total, and Dutch airline KLM canceled a total of 42 flights. Declan Kearney, spokesman for Aer Lingus, said it had canceled 22 flights between Ireland and Scotland.
"We take the advice given to us," he said. "We have no reason to question the advice being given to us by the aviation authorities at this time. We need to accept what the experts in this area are telling us."
The ash cloud forced President Barack Obama to shorten a visit to Ireland on Monday, and has raised fears of a repeat of huge travel disruptions in Europe last year.
Last year, European aviation authorities closed vast swaths of European airspace as soon as they detected the presence of even a small amount of volcanic ash in the atmosphere. This year, they are trying a more sophisticated approach.
Aviation authorities will give airlines information detailed information about the location and density of ash clouds. Any airline that wants to fly through the ash cloud can do so, if it can convince its own national aviation regulators it is safe.
The closures are already affecting travel plans across Europe. Officials at Spanish soccer team Barcelona, which plans to travel to London on Thursday for Saturday's Champions League final against Manchester United at Wembley Stadium, say they are monitoring the ash cloud disruption and could change their departure date.
In Ireland, a couple who were due to fly to Edinburgh for a friend's wedding were told their flight had been canceled. Anne and Damien Farrell decided on the spot to reclaim the car they'd just parked in Dublin Airport's long-term parking lot, drive the 100 miles (160 kilometers) north to Belfast, and take the ferry to the Scottish port of Stranraer.
"Fortunately we have a day of lead-in time before the wedding party gets going, otherwise we'd be up a certain creek without a paddle," said Damien Farrell, 29.
Meera Selva in London, Slobodan Lekic in Brussels, Shawn Pogatchnik in Dublin, Ben McConville in Edinburgh, Melissa Eddy in Berlin and other AP writers across Europe contributed to this report.