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.
MileCards.com, which compares credit cards that offer travel rewards, analyzed U.S. Department of Transportation data for more than one million flights from 2010 to 2015 to identify the riskiest airlines, airports, and routes for cancellations between Dec. 20 and Dec. 31.
"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.
Regional airlines that fly under contract for the big airlines -- American, Delta, and United -- canceled more than 4 percent of flights around the December holidays, compared with 1.6 percent of flights for the big airlines themselves.
Low-cost Spirit and JetBlue canceled December flights at twice the rate of other big airlines between 2010 and 2015. JetBlue's cancellation rate was attributed, in part, to operating many short-haul flights in the Northeastern United States, often prone to weather delays.
Alaska and Hawaiian Airlines, with limited operations in the Midwest and the East Coast, had almost no cancellations around Christmas. Delta Air Lines had the best cancellation rate, 1.5 percent, among the global U.S. carriers.
Airports with the worst December holiday-cancellation rates were in the New York area: Newark Liberty, John F. Kennedy, and LaGuardia, which had cancellation rates more than twice the national average. The remaining of the 10 worst airports for the most canceled flights were Chicago-O'Hare, Cincinnati, Boston, Cleveland, Washington-Reagan National, Raleigh-Durham, and Milwaukee. Philadelphia International Airport ranked No. 14 among the 50 busiest U.S. airports, with a 2.7 percent cancellation rate.
Airports with the fewest cancellations were Honolulu, Oakland, Seattle, and Las Vegas -- cities that typically don't see much snow.
Among major connecting hubs, Salt Lake City and Phoenix had the lowest cancellation rates.
Travel routes to avoid during the December holidays were out of Newark Liberty International Airport: Newark to Pittsburgh; Newark to Manchester, N.H.; and Newark to Washington-Reagan flights were canceled, respectively, 20 percent, 17 percent, and 15 percent of the time, "a startling high rate" over the course of six years, MileCards noted.
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.
"Anyone who wants a refund, we've been giving them refunds if their flight was canceled," Faulkner said.