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.