BERLIN (Dispatches) – Airlines lost at least $1.7 billion in revenue during the volcanic ash crisis, an industry group said Wednesday as the debate heated up over European governments' handling of a week of airspace closures. Planes were flying into all of Europe's top airports — London's Heathrow, Paris' Charles de Gaulle and Frankfurt. Still experts predicted it could take days — even more than a week — to clear a backlog of stranded passengers after about 102,000 flights were canceled around the world. Eurocontrol, the air traffic control agency in Brussels, said 21,000 of the continent's 28,000 scheduled flights will go ahead on Wednesday, as airlines patched together operations with planes and flight crews scattered all over the globe Giovanni Bisignani, the head of the International Air Transport Association, called the economic fallout from the six-day travel shutdown ""devastating"" and urged European governments to examine ways to compensate airlines for lost revenues, as the U.S. government did following the Sept. 11, 2001 terror attacks. Bisignani told a news conference Wednesday in Berlin that airlines $400 million each day during the first three days of grounding. Spain, meanwhile, has become a key emergency travel hub, arranging for hundreds of special flights to move over 40,000 people stranded by the travel disruptions. Its airports and airspace have mostly remained open throughout the crisis. French transport minister Dominique Bussereau estimated all of Air France’s long-distance flights to and from France would fly Wednesday, and 60 to 70 percent of its mid-range flights. In Iceland, there was no sign that the eruption at the Eyjafjallajokull (ay-yah-FYAH-lah-yer-kuhl) volcano ending soon, according to Pall Einarsson, a geophysicist at the ainstitute of Earth Sciences in Reykjavik. (See page 2 for domestic flights) ------Kalta volcano For all the worldwide chaos that Iceland's volcano has already created, it may just be the opening act. Scientists fear tremors at the Eyjafjallajokull volcano could trigger an even more dangerous eruption at the nearby Katla volcano — creating a worst-case scenario for the airline industry and travelers around the globe. A Katla eruption would be 10 times stronger and shoot higher and larger plumes of ash into the air than its smaller neighbor, which has already brought European air travel to a standstill for five days and promises severe travel delays for days more. The two volcanoes are side by side in southern Iceland, about 12 miles (20 kilometers) apart and thought to be connected by a network of magma channels. Katla, however, is buried under ice 550 yards (500 meters) thick — the massive Myrdalsjokull glacier, one of Iceland's largest. That means it has more than twice the amount of ice that the current eruption has burned through — threatening a new and possibly longer aviation standstill across Europe. The last three times Eyjafjallajokull was erupted, it triggered the eruption of Kalta. In the 1980s Kalta eruption created severe famines around the world, and changed the global “climate so drastically that New Jersey recorded its largest snowfall and Egypt one of its most enduring droughts,” reports Rober Boyes in the Times. With a population of 300, the coastal village of Vik has been covered in 3 millimeters of ash from Eyjafjallajokull eruption, but the real concern in Kalta. Residents would have two to three hours to reach the safety of a shelter if the volcano erupted and caused the ice to melt quickly. “We have practiced and can do it in 30 minutes,” says Svenn Palsson, the 48-year-old mayor of Vik. Katla showed no signs of activity Tuesday, according to scientists who monitor it with seismic sensors, but they were still wary.

Photo: People wait in the departure hall to board flights operating from Gatwick airport, near London, England, Wednesday, April 21, 2010. (Photo: AP)