Travelers are feeling the effects of Hurricane Sandy at San Francisco International Airport, where hundreds of arriving and departing flights to the East Coast have been canceled. More cancellations are expected.

"It is just starting to make landfall; it depends on what happens next," said airport spokesman Doug Yakel. "We are seeing some flights cancelled to Washington and New York for tomorrow. The next 12 hours will be a wait-and-see."

There were 60 flights cancelled Sunday and 150 on Monday to and from San Francisco.

Given the widespread publicity, however, Yakel said most passengers checked the status of flights beforehand and have stayed away from the airport.

"We are not seeing a lot of stranded passengers," he said.

At Oakland International Airport, two JetBlue flights were canceled Monday.

However, most of the transcontinental flights from Oakland have stopovers in such cities as Chicago, Denver and Las Vegas, so the effect might not be apparent, said spokesman Scott Yamasaki.

The storm has canceled and grounded thousands of domestic and international flights in the U.S. northeast Monday and upended travel plans across the globe, stranding passengers from Hong Kong to Europe.

Major carriers such as American Airlines, United and Delta canceled 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.

The cancellations have already surpassed those from last year's damaging Hurricane Irene.

They're now on par with a major winter storm in early 2011. Back then, 14,000 flights were scrapped over four days.

Delays rippled across the U.S., affecting travelers in cities such as Los Angeles 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.

About one-quarter of all U.S. flights travel in or out of New York airports each day. So cancellations there can dramatically impact travel in other cities.

This report includes information from Staff Writer Bob Norberg and the Associated Press.