Washington ? The blackout in the eastern United States and parts of Canada disrupted planes, trains and automobiles, leaving millions of travelers stuck in traffic jams, airport terminals and rail stations.

Most flights were halted for several hours Thursday in and out of Kennedy and LaGuardia airports in New York, as well as Cleveland, Newark, N.J., Toronto and Ottawa. All six airports resumed full operations Thursday night.

Other airports also were affected. The FAA and the airlines said they did not know how many flights overall were affected.

Amtrak halted travel between New Haven, Conn., and Newark, including New York’s Pennsylvania Station. New York subways stopped in their tracks, forcing evacuations of passengers. The Port Authority Bus Terminal was evacuated.

Congestion was common in cities where power was out, as signals went dark.

Delays were expected to extend into today as the airlines and Amtrak worked through the night to get planes and trains into position to handle the backlog.