JACKSONVILLE, Fla. -

Dozens of flights at Jacksonville International Airport were among an estimated 7,200 canceled across the United States on Monday due to Hurricane Sandy.

The massive storm threatens to bring a near halt to air travel in and out of about one-third of the nation's busiest airports for at least two days.

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 7,500 flights had been canceled for Monday and Tuesday, almost all related to the storm.

At JIA on Monday, eight flights to New York, eight flights to Newark, six flights to Philadelphia, three flights to Baltimore, one to Boston and 14 to Washington D.C. were all canceled. More than 20 flights were canceled Sunday.

Passengers stranded in Jacksonville were being told that flights to northeast U.S. cities would likely not take off until Wednesday.

Friends Mitchell Bedard and Ryan McGurn were trapped at JIA on Monday, far from home.

"Well, we were supposed to go back to Providence, Rhode Island, today, but we're stranded here until Wednesday," Bedard said.

They flew in to Florida for a festival in Gainesville, never anticipating Sandy could stop them from heading north.

"Just pretty much figured out we were going to be stranded here with zero dollars for the next few days, sleeping on these chairs," McGurn said.

It's not just people stranded at the airport. Several airplanes are stuck on the runway, waiting for the storm to pass.

"It's a day to day call and it is handled by each one of the airlines," said Michael Stewart, of JIA External Affairs. "So it depends on how they want to move their equipment around, what airports in the northeast reopen and what equipment is there, and there's a lot of factors."

JIA is encouraging travelers to contact their airline directly to find out about cancellations and reminding passengers to be patient.

"It's not something that the airlines or the airport can do anything about," Stewart said. "Safety is the primary concern by the aircraft when they are moving people."

Until the forecast clears there's no definite date when the flight schedule will get back to normal.

Delays have rippled across the U.S., affecting travelers in cities such as San Francisco to Chicago. 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 London, Paris, Tokyo and Hong Kong.

Businessman Alan Shrem was trying to return home to Boca Raton, Florida. His Monday morning Cathay Pacific flight from Hong Kong to New York's Kennedy airport was canceled.

He learned he could be stuck in Hong Kong for nearly a week because the next available seat was Nov. 4. He was put on a waiting list for seats that could become available earlier.

"They just say: Yeah, it's a pretty big waiting list," said Shrem, throwing up his hands. In the meantime, he'll have to fork out $400 a night to continue staying at a nearby hotel. The airline won't pay for accommodation for stranded passengers if delays are weather related.

Forecasters say Hurricane Sandy is about 310 miles (505 kilometers) southeast of New York City, and the center of the storm is expected to be near the mid-Atlantic coast on Monday night. The National Hurricane Center said early Monday that the storm has top sustained winds of 85 mph (140 kph), with higher gusts. Sandy is on track to collide with a wintry storm moving in from the west and cold air streaming down from the Arctic.

Airports in the metropolitan New York City area are open, but air carriers are not operating.

The Port Authority of New York and New Jersey said Monday that travelers shouldn't even try to go to Kennedy, Newark Liberty, LaGuardia and Stewart airports.

Air travel in the Northeast started getting complicated on Sunday, when passengers were reporting multi-hour wait times at airline call centers.

Eileen Merberg, 50, was booked on a United flight from her home in Rochester, N.Y. to New Orleans, connecting at Washington D.C.'s Dulles airport.

She received an email saying the Washington flight was canceled. United rebooked her first on a flight through Newark and, when that flight was also canceled, on another flight through Chicago.

By that point, she already had told the higher education conference that she was scheduled to speak at that she wouldn't be coming. She tried to cancel her flight over the phone. After two lengthy waits -- her cellphone battery ran out during the first one -- she just hung up.

International travelers would have to wait to get to the East Coast of the U.S. 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.