Holiday travelers found a lump of coal in their carry-on bag after airlines canceled thousands of flights, blaming winter weather that’s blasted the country with cold and snow. Of the 2,943 flights cancelled on Tuesday across the nation, as reported by FlightAware, 2,546 were Southwest Airlines flights after the airline announced Monday that it would only fly one third of its regular scheduled flights. FlightAware, a flight tracking service, is predicting 2,510 cancellations for...