New York's three major airports will be operating under reduced schedules on Thursday as flight services start returning to normal following Superstorm Sandy.

The busy Northeast travel corridor ground to a halt when Sandy slammed into the East Coast on Monday, flooding train tunnels, cutting power and shutting down regional airports.

John F. Kennedy International Airport and Liberty Airport in Newark, N.J., which reopened Wednesday, will continue to offer limited service on Thursday.

LaGuardia Airport, which had remained closed amid storm-related damage, said it is due to reopen Thursday morning with reduced service. LaGuardia has just two runways that jut out into bays and are only a few feet above sea level. They were inundated by Sandy's surge.

American Airlines and Delta Air Lines and Southwest Airlines said they plan to restart LaGuardia flights on Thursday morning, with Southwest joining them in the afternoon. Delta spokesman Morgan Durrant said the airline intends to start landing planes around 7 a.m. and hopes to operate half of its normal LaGuardia schedule, while American is aiming for 70 percent.

International travel was normalizing, helping stranded passengers around the world to get on their way.

In the U.K., Virgin Airlines said it had flown an extra flight on Wednesday to clear a backlog of passengers, and on Thursday was operating its normal four-flights-a-day service to New York. It also planned to fly normal schedules to Newark, Boston, and Washington, D.C.

British Airways said it was flying all but one of its 11 daily services to New York as well as normal services to Newark and its other U.S. East Coast destinations.

The airline said it was operating an extra flight to Newark and had added more ticket machines at terminals in JFK and Liberty Airport to help speed customers through the rebooking and check-in process.

Airports in Washington and Philadelphia reopened on Tuesday.