New York CNN —A punishing winter storm that dumped multiple feet of snow across much of America led to widespread flight cancellations over the Christmas holiday. By Monday, air travel was more or less back to normal – unless you booked your holiday travel with Southwest Airlines. About 87% of Tuesday’s US flight cancellations are Southwest, according to flight tracking website FlightAware. Employees also said they have not been able to communicate with the airline, the president of the union that represents Southwest’s flight attendants told CNN Monday. A lack of toolsThe problems Southwest faces have been brewing for a long time, said Captain Casey Murray, the president of the Southwest Airlines Pilots Association.