Stranded Southwest passengers across the country are struggling with a second day of mass flight cancellations by the nation's largest domestic airline. Southwest has canceled 1,006 Sunday flights as of 11 a.m. ET, according to flight tracker FlightAware. That's 27% of the the airline's scheduled flights and the highest of any U.S. airline by a wide margin. Southwest's Sunday cancellation are on top of 808 cancellations on Saturday, or nearly one in four flights. This during a busy travel weekend given a federal holiday on Monday. #southwestairlines