European officials are hoping half of the usual number of flights will take to the sky on Monday to somewhat ease four days of airlines paralysis caused by ash from a volcano in Iceland.

The Dutch airlines KLM flew several test flights and says most European airspace is safe despite the ash. Italy and Austria say they will reopen airports on Monday. Iceland's Meteorological Office say the column of rising ash has eased back to four kilometers from as high as eleven kilometers when it began erupting on Wednesday. Sixty-three thousand flights have been cancelled since Thursday. This has stranded millions of passengers and cost airlines and airports hundreds of millions of dollars.