Last Updated Monday 1:39 p.m. ET
Hurricane Sandy grounded thousands of flights in the U.S. northeast Monday and upended travel plans across the globe, stranding passengers from Hong Kong to Europe. The massive storm threatens to bring a near halt to air travel for at least two days in a key region for both domestic and international flights.
Major carriers such as American Airlines, United and Delta cancelled all flights into and out of three area airports in New York, the nation's busiest airspace.
According to the flight-tracking service FlightAware, nearly 10,000 flights had been canceled for Monday and Tuesday, almost all related to the storm.
All flights out of Philadelphia International Airport were canceled Monday. Boston's Logan Airport was open, but most flights were canceled. The Metropolitan Washington Airports Authority said both Dulles International and Reagan Washington National airports remain open Monday, though most flights in and out of are canceled. All airline operations at BWI were shut down.
Delays rippled across the U.S., affecting travelers in cities such as San Francisco and Chicago (where more than 400 flights at O'Hare International Airport and nearly 100 at Midway International Airport were canceled). Disruptions spread to Europe and Asia, where airlines canceled or delayed flights to New York and Washington from cities that are major travel hubs including Berlin, Paris, Tokyo and Hong Kong.
The Port Authority of New York and New Jersey, which runs five airports in the area, advised passengers to check with their carriers before heading to the airport.
Passengers on Sunday were reporting multi-hour wait times at airline call centers.
Airlines also promised to update their Facebook pages and Twitter feeds with the latest information. To cancel, passengers should call the airline directly. Some airlines also allow changes to be made on their websites.
All major airlines are offering waivers to customers who wish to reschedule their flights without incurring the typical fee of up to $150. The offers cover passengers flying in or out of just about any airport from Latin America to New Hampshire. Most waivers for travel in the Northeast are only valid Monday through Wednesday.
A spokesman for United Airlines parent United Continental Holdings Inc. said the carrier has suspended an unspecified number of flights to New York and Washington-area airports beginning Sunday evening with plans to resume Tuesday as conditions permit.
JetBlue Airways Corp. expects its cancellations from Sunday through Tuesday to total about 1,200. The airline has hubs at Kennedy airport and Boston's Logan. Rob Maruster, chief operating officer of JetBlue, hopes to resume New York flights on Wednesday morning. But he's worried about flooding of JFK's runways since they are all basically at sea level and near bodies of water.
Delta Air Lines Inc. has canceled 2,100 flights over the three days. American Airlines has scrapped 1,000 flights, including 260 on regional affiliate American Eagle.
American Airlines and American Eagle canceled 140 flights Sunday and canceled another 1,431 flights Monday through Wednesday due to Hurricane Sandy, the company said.
US Airways said it had suspended all operations at the three New York airports Sunday evening and Monday and at Philadelphia and Washington on Monday.
Disruptions on the East Coast of the U.S. also affect international carriers. All flights from Paris to Boston, New York, Philadelphia and Washington - a total of 14 - were canceled. Air France has canceled four into JFK and two departures.
Frankfurt airport canceled 12 flights, with German carrier Lufthansa scrapping three to the Northeast and one out of Newark. British Airways had to cancel all its flights to and from New York, Newark, Baltimore, Washington DC, Boston and Philadelphia - a total of 20.
Eight flights out of Tokyo's Narita International Airport to New York, Newark and Washington were canceled Monday.
Hong Kong's Cathay canceled its two daily flights to New York for Monday and Tuesday and Air India said its daily flights to Newark and JFK had halted since Sunday.
South Korean flag carrier Korean Air delayed a flight scheduled to leave Incheon International Airport for JFK on Monday by 22 hours. Asiana Airlines delayed its JFK flight from Seoul by 26 hours.
Last year Irene caused the cancellation of nearly 14,000 flights in a four-day period.
Amtrak has canceled service across the northeastern U.S., including all service north of New York. Nearly all service across the Eastern Seaboard will be canceled starting Monday.
Amtrak says it has not yet determined when train services will resume. Alternate transportation is not available.
Some trains will continue to run in Florida and the Carolinas. A news release said customers can receive a refund or voucher for future travel.
New York, Philadelphia, Washington and Baltimore moved to shut down their subways, buses and trains in advance of the massive storm.
With a daily ridership of more than 5 million, New York City's subway system is by far the nation's largest. The service suspension was the second in two years, following a shutdown during Tropical Storm Irene last year.
The Boston transit authority said all service would be suspended effective 2 p.m. today.
On Sunday, New York Gov. Andrew Cuomo said the decision to shut down the New York City area's bridges and tunnels would be made on a case-by-case basis. It was announced Monday that the Brooklyn-Battery and Holland Tunnels would be closed at 2 p.m.
East River Ferry service which locations in midtown and lower Manhattan with Queens and Brooklyn was also shut down in advance of the storm.
The Cape May-Lewes Ferry that runs between Delaware and New Jersey also shut down over the weekend and will remain closed through Tuesday.