Airlines grounded by the Icelandic volcano ash alarm are already counting the potentially colossal cost. The European air traffic agency Eurocontrol said that some 250 flights had been cancelled in British airspace alone.
The eruption from Grimsvotn, which began on Saturday, is said to be more powerful than the volcanic eruption which caused trouble last year. Eurocontrol says that if the ash rate keeps up, the cloud could reach French and Spanish airspace by Thursday.
Authorities have backed more relaxed rules on flying through ash after being criticised for being too strict the last time. Scientists are saying the type of ash caused by the latest eruption does not spread as much.
Ash from another Icelandic volcano last year caused 100,000 flights to be cancelled, stranding 10 million passengers around the globe and losing the industry an estimated 1.7 billion euros in revenue.