Businesses in the United States and Canada are scrambling to return to normal after the massive power outage brought many operations to a halt.

Airlines have canceled hundreds of flights in the affected areas, stranding thousands of travelers and disrupting travel worldwide. Air Canada suspended operations after its primary and back-up power systems failed.

Many workers crowded the streets of Manhattan on Friday, trying to make it to work and elsewhere as transportation was severely limited. Gas stations have been closed and cellular phone service interrupted.

Amtrak, which runs trains along the Northeastern corridor, has restored limited service between Washington and New York, but not yet to Boston.

Restaurants were forced to give away or throw out perishable food, while some auto industry factories in Detroit had to shut down on Thursday.

Many tourists in New York City slept on the streets as hotels - some of them high-rise buildings without working elevators - were evacuated. They were given sheets and pillows to make their night on the sidewalk more comfortable.

The New York Stock Exchange opened on time Friday, with Mayor Michael Bloomberg ringing the opening bell.