Morrisville, N.C. — Travel to the Northeast is creaking back into motion Thursday now that Superstorm Sandy has receded and has allowed workers to check runways for water damage.

All of New York's three major airports were open Thursday morning under reduced schedules, and some flights were departing at Raleigh-Durham International Airport.

Still, airport officials urged travelers to check their flights to Northeast airports before heading to the airport.

The busy Northeast travel corridor ground to a halt when Sandy slammed into New Jersey on Monday evening.

Train tunnels flooded, power went out, and forecasts of high winds forced airlines to cancel more than 19,000 flights nationwide, including 2,820 on Wednesday, according to FlightStats.

Most Northeast rail service remain suspended Thursday. Locally, some buses were running in New York City and subway service was also expected to resume Thursday.

The loss of East Coast flights stranded tourists in New York and kept travelers stuck in Hong Kong. The lack of trains left suburban commuters without a way into work.

The first trickle of air travelers since the storm hit reached New York Wednesday after John F. Kennedy International and Liberty Airport in Newark, N.J., both opened. Laguardia Airport reopened Thursday morning.

American Airlines and Delta Air Lines and Southwest Airlines restarted LaGuardia flights on Thursday morning, with Southwest was expected to join them in the afternoon.

Delta spokesman Morgan Durrant said the airline hopes to operate half of its normal LaGuardia schedule, while American is aiming for 70 percent.

"There is some damage to our offices and facilities," American Airlines spokeswoman Andrea Huguely said. "It's not pretty, but we can operate. Our employees are cleaning up for our customers."

Airline employees will face challenges getting to work. Not only is mass transit severely restricted, but driving in will be more difficult.

Mayor Michael Bloomberg said that only cars with at least three passengers would be allowed to cross a bridge or enter a tunnel.

"There are a lot of contingencies before we can reopen at LaGuardia," Southwest spokesman Paul Flaningan said. "It's still barricaded at the front entrance, which makes drop-offs from taxis and buses difficult."

Amtrak said it plans to restore some service on Friday to and from New York City, which has been without intercity train service since it was walloped by Superstorm Sandy.

The railroad said the removal of water from flooded train tunnels under the Hudson and East rivers is continuing so that repairs to tracks, signals and power systems can be made. A Friday schedule is expected to be released Thursday.

Newark's Liberty airport has been restored, but Northeast Regional service between Newark and New Haven, Conn., and Acela Express service for the length of the Northeast Corridor are canceled for Thursday. Empire Service between New York City and other cities in the state and Canada were canceled for Thursday

Airlines continued to waive fees to change tickets for flights to New York airports. Delta and United said that anyone who planned to fly there through Saturday could change their ticket. However, the rebooked travel still had to begin by Nov. 9, giving travelers a relatively narrow window to make their trip.

American's waiver was broader, covering New York tickets through Nov. 7, and allowing rebooked travel through Dec. 20.

Airports in Washington and Philadelphia reopened on Tuesday.