Hurricane Sandy grounded thousands of flights in the U.S. northeast on 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, JetBlue and Delta planned to cancel 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 7,500 flights had been cancelled for Sunday and Monday. Both Philadelphia International Airport and Newark International Airport, a hub for United Airlines, each had more than 1,200 cancellations for the two days.

Delays rippled across the U.S., affecting travellers in cities such as San Francisco to Chicago, and disruptions spread to Europe and Asia, where airlines cancelled or delayed flights to New York and Washington from cities that are major travel hubs including Berlin, Paris, Tokyo and Hong Kong.

At New York’s LaGuardia on Sunday, crowds filled the American Airlines terminal near midday, with families sitting on the floor waiting for a flight out any flight out.

The Port Authority of New York and New Jersey, which runs five airports in the area, said it expects all carriers to cease operations Sunday night. It 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.

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., which flies out of JFK, said it has canceled more than 1,000 flights from Sunday through Wednesday morning.

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 impact international carriers. Air France has cancelled four Monday flights into JFK and two departures. Lufthansa cancelled three flights to the Northeast and one flight out of Newark.

A total of eight flights out of Tokyo’s Narita International Airport to New York, Newark and Washington were cancelled Monday.

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.

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