BRUSSELS — Eurocontrol says most flights between Europe and North America will be delayed on Saturday due to a spreading cloud of volcanic ash stretching across much of the northern Atlantic.
Flights will have to be rerouted north and south of the 1,200-mile (2,000-kilometer) -long cloud stretching from Iceland to northern Spain, adding up to an hour of flying time in either direction.
On average, 600 airliners make the ocean crossing every day.
The plume of ash, which forced the closure of four airports in northern Spain on Saturday, is expected to expand into southern France during the day.
Since the ash is reaching altitudes of up to 35,000 feet (10,000 meters), where most trans-Atlantic flights take place, it will effectively block the usual flight tracks.