Thousands of travelers were stranded at airports or stuck on hold trying to rebook flights this week as a massive storm snarled travel in the U.S. and Canada ahead of the holidays.

As of Friday afternoon, more than 4,800 flights into or out of U.S. airports had been canceled, according to the flight tracking service FlightAware.

Wendell Davis, who plays basketball with a team in France, was scheduled to fly from Paris to his hometown of Columbus, Ohio, on Wednesday. After multiple cancellations, Davis was still at O’Hare airport in Chicago on Friday. He debated driving to Columbus but decided not to. Instead, he booked a hotel room while he waits for a scheduled flight to Cincinnati on Christmas Day.

“Everyone’s going through the same problems right now,” he said with a laugh. “We’ve just got to stay positive. Anger is not going to help us at all.”

Staying calm —— and knowing your rights —— can go a long way if your flight is canceled, experts say. Here’s some of their advice for dealing with a flight cancellation:

MY FLIGHT WAS CANCELED. WHAT NEXT?

If you still want to get to your destination, most airlines will rebook you for free on the next available flight as long as it has seats, according to the U.S. Department of Transportation.

If you want to cancel the trip, you are entitled to a full refund, even if you bought non-refundable tickets. You’re also entitled to a refund of any bag fees, seat upgrades or other extras.

Kurt Ebenhoch, a consumer travel advocate and former airline executive, stressed that travelers are eligible for a refund, not just vouchers for future travel. If you do take a voucher, make sure you inquire about blackout dates and other restrictions on its use.

WILL I HAVE TO PAY A CHANGE FEE IF I REBOOK MY FLIGHTS?

Major airlines —— including Delta, American, Southwest, Air Canada, Alaska, Frontier and Spirit —— are waiving change fees during the storm, which gives travelers more flexibility as they shift their plans. But Ebenhoch said travelers should read the fine print carefully. If you book a return flight outside the window that the airline sets, you may have to pay for the difference in fares, for example.

CAN I ASK TO BE BOOKED ON ANOTHER AIRLINE’S FLIGHT?

Yes. Airlines aren’t required to put you on another airline’s flight, but they can, and sometimes do, according to the DOT. Jeff Klee, CEO of CheapAir.com, recommends researching alternate flights while you’re waiting to talk to an agent. Agents are typically under a lot of pressure when a flight is canceled, so giving them some options helps.

Ebenhoch also suggests looking for alternative airports that are close to your original destination.

IS THE AIRLINE REQUIRED TO GIVE ME A HOTEL ROOM, OR OTHER COMPENSATION?

No. Each airline has its own policies about providing for customers whose flights are canceled, according to the DOT. But many airlines do offer accommodations, so you should check with their staff.

I’M FACING A LONG WAIT TO REBOOK. WHAT SHOULD I DO?

If someone in your traveling party is at a higher level in a frequent flier program, use the number reserved for that level to call the airline, Ebenhoch said. You can also try calling an international help desk for the airline, since those agents have the ability to make changes.

HOW CAN I AVOID THIS IN THE FUTURE?

Ebenhoch said nonstop flights and morning flights are generally the most reliable if you can book them. If you’re worried about making it to the airport in time for a morning flight, he said, consider staying at a hotel connected to the airport the night before. And consider flying outside of busy dates; this year, the U.S. Transportation Safety Administration is expecting big crowds on Dec. 30, for example.

Klee recommends comparing airlines’ policies on the DOT’s service dashboard: https://www.transportation.gov/airconsumer/airline-customer-service-dashboard. He also suggests reserving multiple flights and then canceling the ones you don’t use, as long as the airline will refund your money or convert it into a credit for a future flight.