If you want to get to Grandmother's house for Christmas or Hanukkah, the airport, airline, and route you choose can make a difference.
Carriers with the most flight cancellations around the December holidays are Spirit Airlines and JetBlue Airways. And the chances of your flight being canceled are greater the two days after Christmas than the two days before.
Regional airlines that operate flights for the big airlines -- such names as American Eagle, SkyWest, and ExpressJet -- cancel more trips than the major carriers do.
Flights are canceled five times more often around Christmas than at Thanksgiving. The reason: weather. If you are making a flight connection to get to the West Coast, it's better to go through warm-weather Phoenix and not through blizzard-prone Chicago.
"Weather is the biggest factor for flight cancellations in December, by far," said Brian Karimzad, director of MileCards. "You have one or two nasty snow or ice events that jam up two or three big airline hubs, and it cascades throughout the system."
Among the report's key findings:
Dec. 26 and 27 are the worst days for cancellations, with 5 percent of flights scrubbed. For fliers trying to get home before the holidays, Dec. 23 and 24 had the fewest cancellations. Flights on Christmas Day were three times more likely to be canceled than on Christmas Eve.
Last weekend, a foot of snow fell in Denver, forcing hundreds of flight cancellations and delays that stranded travelers and caused a ripple effect across the country.
Denver-based Frontier Airlines could not get planes and flight crews into Denver, its hub, which caused Frontier flights to be canceled as far away as Philadelphia, Nashville, and Raleigh.
In all, 5,240 U.S. flights were canceled and 35,291 were delayed between Thursday, Dec. 15, and Sunday, Dec. 18, according to the flight-tracking website FlightAware.
"We had crews stuck in other parts of the country who couldn't get to Denver to fly," said Jim Faulkner, spokesman for Frontier. "We had the plane in Denver ready to go to Philadelphia, but no crew. We started to catch up Sunday and Monday, but we are still trying to get the crews and planes in the right spots."
Southwest, Spirit, JetBlue, and Frontier do not have "interline" agreements with other domestic airlines, so if you get delayed, you can fly only one of their own later flights.