Airlines cancel 3,900 U.S. flights Friday as winter storm snarls travel

Airlines canceled over 3,900 U.S. flights on Friday as a massive winter storm snarled airport operations around the United States and frustrated thousands of holiday travelers.

The cancellations follow nearly 2,700 canceled flights on Thursday, according to flight tracking website FlightAware. Passenger railroad Amtrak has canceled dozens of trains through Christmas, disrupting holiday travel for thousands.

The Federal Aviation Administration (FAA) imposed ground stops or delays for de-icing at a number of U.S. airports because of winter weather. It said "severe winter weather moving across the Great Lakes into the Northeast will have a major impact" on flights, adding that "flight delays are likely from Boston to D.C. Metropolitan area airports, Seattle-Tacoma and Portland International Airports and Aspen" in Colorado.

Seattle-Tacoma International Airport had 40% of departing flights canceled as of 8:30 a.m. PT (1430 GMT). The FAA early on Friday issued a ground stop there due to snow and ice.

More than 40% of departing flights at Detroit Metro were canceled and 18% at Chicago O'Hare, which noted wind gusts of 40 to 50 mph are expected in Chicago on Friday.

Another 3,800 U.S. flights were delayed on Friday - including more than 14% of those operated by American Airlines , United Airlines, Delta Air Lines and Southwest Airlines.

Southwest canceled 800 flights Friday, about one-fifth of all its scheduled flights, while Alaska Airlines canceled 321, or 41%, of its flights.