With the cloud drifting south and east across Britain, the country's air traffic service banned all non-emergency flights until at least 7 a.m. Friday. Irish authorities closed their air space for at least eight hours, and aviation authorities in Denmark, Norway, Sweden and Belgium took similar precautions.
The move shut down London's five major airports including Heathrow, a major trans-Atlantic hub that handles over 1,200 flights and 180,000 passengers per day. Airport shutdowns and flight cancellations spread eastward across Europe — to France, Belgium, the Netherlands, Denmark, Ireland, Sweden, Finland and Switzerland — and the effects reverberated worldwide.
French officials shut down all flights to Paris and 23 other airports.
Airlines in the United States canceling some flights to Europe and delayed others. In Washington, the Federal Aviation Administration said it was working with airlines to try to reroute some flights around the massive ash cloud.