As Hurricane Sandy churned toward landfall, airlines in the Northeast prepared to halt air travel for a second day Tuesday at airports between Washington and Boston, including Philadelphia International Airport.

US Airways, which operates a hub in Philadelphia, scrubbed 1,641 flights systemwide Monday, a little more than half of its daily schedule. US Airways announced at noon Monday that it would cancel all flights again Tuesday in Philadelphia, Washington, Boston, New York, and Newark, N.J.

Ninety percent of Tuesday flights in and out of Philadelphia were suspended.

"Our goal now is to resume operations at all locations on Wednesday morning," spokesman Todd Lehmacher said. "Obviously that will depend on the weather and assessing any damage that this storm may cause."

"The safety of customers, employees and equipment, of course, is key and will factor into our decision to resume operations," Lehmacher said. "We also need to assess our infrastructure once the storm passes before making a definitive decision."

All airlines moved aircraft out of Philadelphia on Sunday as the storm approached to keep equipment out of harm's way. US Airways parked planes in Pittsburgh and Charlotte, N.C., Lehmacher said.

Philadelphia's airport remained open Monday, even though no flights came or went.

"The airport is available and open if there is a plane that needs to land," airport spokeswoman Victoria Lupica said. Cargo carriers United Parcel Service and FedEx also suspended air service here.

Four airport restaurants and concessions remained open round-the-clock to accommodate Division of Aviation, airline management, and concession workers.

"This is very similar to how we manage a snow weather emergency. The minute we hear a storm like this is coming, we mobilize," Lupica said. "We have our engineers, all our operations people, here."

Airport staff confer with airlines, the Federal Aviation Administration, the Transportation Security Administration, and police and fire personnel throughout the day and night to monitor the storm.

On Sunday, four passengers spent the night at the airport. No passengers were in terminal buildings Monday, Lupica said.

According to the flight-tracking service FlightStats, 7,447 flights were canceled Monday, and by Monday afternoon 1,814 flights were canceled for Tuesday.

Hurricane Sandy has caused 10,630 flight cancellations since Sunday, FlightStats said.

After the hurricane heads out, airlines will reposition aircraft and crew members. Some US Airways planes will be flown to Philadelphia empty to get them here, Lehmacher said.

"That's the logistical challenge our operations folks in Pittsburgh deal with, scheduling the crews and routing the aircraft," he said.

US Airways' inbound international flights to Philadelphia stayed in Europe Monday, with the exception of the flight from Tel Aviv, Israel, which landed in Charlotte.

Transatlantic fights bound for Philadelphia will remain in Europe until Wednesday, US Airways said.

Philadelphia-area passengers were accommodated in hotels, while travelers connecting to other cities were put on flights out of Charlotte, Lehmacher said.