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Canceled tags litter the flight board at Albany International Airport, in Albany, N.Y., Monday morning, Oct. 29, 2012. Many flights in the northeast were canceled because of Hurricane Sandy. (AP Photo/Times Union, Will Waldron)

Hurricane Sandy is tying up air travel across the country, causing flight cancellations at all three Bay Area airports, and experts warned the tie-ups could continue through midweek.

More than 7,000 flights in the United States were canceled on Monday, according to Flightstats.com, a website devoted to on-time performance of airlines and airports around the world.

"From Boston to Norfolk (Va.), nothing is moving," said Joe Brancatelli, who operates JoeSentMe.com, a website for business travelers. He estimates some 700,000 travelers could be facing flight cancellations or severe delays.

"This started yesterday afternoon," Brancatelli said Monday. "American Airlines has already said they aren't moving anything tomorrow on the East Coast."

Affected airports include JFK International in New York, Newark Liberty International, Baltimore Washington International, Reagan National and Dulles International in Washington, D.C., Philadelphia International and Logan International in Boston.

On Monday, Mineta San Jose International Airport reported JetBlue flights to Boston and New York City had been canceled, while Oakland International Airport said JetBlue flights to New York City and Washington, D.C., had been canceled. San Francisco International Airport said 150 East Coast flights -- inbound and outbound -- have been grounded.

Beyond those cancellations, scores of other East Coast-bound passengers leaving the Bay Area with connecting flights in other cities were apt to be stranded midway to their destination, airport officials said. They urged passengers to check airline websites for up-to-date information on flights.

"We are seeing some cancellations tomorrow," SFO acting spokesman Doug Yakel said Monday. "Airlines want to be back to normal as soon as they can, but because the storm hasn't hit shore yet, it's hard for them to know when they can return to a normal flight schedule."

Problems may continue in the wake of the hurricane, which is hitting the East Coast with historic intensity. Experts say it could take days for airlines to return to their regular schedules.

"We have a lot of travelers who are having a hard time getting home," said Marc Casto, president of San Jose-based Casto Travel, which annually books more than $50 million in international tickets and $30 million in domestic tickets. "Our advice to them is, 'Get a hotel room and ride it out.'"

The ripple effect of so many airplanes sitting on tarmacs can spread to destinations beyond the East Coast, he said. For instance, Bay Area travelers may not be able to fly to Denver if the plane they were to take originated in a city hit by the hurricane.

"At the end of the day, if you have 10 flights and only eight planes, something has to give," Casto said.

Benicia resident Susan Frost, grounded in New York City by the storm at the end of a vacation, is taking the misadventure in stride.

"We are stranded," she said Monday afternoon, as rain and wind lashed the city. Frost was supposed to take a train to Boston to catch a Tuesday flight to the Bay Area, but both the train and the flight have been canceled.

"It's an inconvenience, but everyone is making the best of it," Frost said. "It's not a big hardship. No one is working (in New York City). The only things that are open are a few pubs and the T-shirt shops."

In all, the canceled flights could cost the U.S. airline industry hundreds of millions of dollars in lost revenue, Brancatelli said. And some passengers might get hit with a change-of-flight fee -- typically $150 -- if the airlines only provide a small window of time during which travelers can switch flights without paying a penalty.

"A lot of people will walk away from their (original) tickets," he said.

United Airlines said on its website that change fees and fare differences will be waived for passengers whose flights have been canceled between Sunday and Wednesday if they reschedule by Nov. 7. After that date, change fees will continue to be waived but fare differences may not, the airline said.

Right now, those trying to change their tickets are having a tough time getting through to airlines, Casto said.

"We had someone on hold for six hours," he said.

Contact John Boudreau at 408-278-3496; follow him at Twitter.com/svwriter.