The skies over Europe reopened Wednesday as airlines scrambled to clear a backlog of flights grounded by a vast cloud of volcanic ash from Iceland.
The European air traffic control agency, Eurocontrol, says about 75 percent of scheduled flights will operate Wednesday. All travel restrictions have been lifted in Britain and Germany.
The task of clearing the backlog of stranded passengers is expected to take days.
An industry official says airlines have lost at least $1.7 billion dollars due to the six-day shutdown. The head of the International Air Transport Association, Giovanni Bisignani, called the economic fallout "devastating" Wednesday, and he urged European governments to look for ways to help airlines recover from lost revenues.
Some airline executives say authorities may have been too hasty to ground flights.
Meanwhile, the head of the International Civil Aviation Authority -- a United Nations agency dealing with air safety -- says there are currently no global standards to determine when it is safe to fly through an ash cloud. Volcanic ash can cause jet engines to shut down in mid flight.
Iceland's Meteorological Office says the volcano entered a new phase Tuesday, and that the ash cloud is diminishing.
The volcano has affected businesses as far away as Africa, China, and Japan, where companies have been unable to ship products to Europe.