The United States federal government says it will investigate Southwest Airlines after the company cancelled thousands of flights, adding to travel chaos initially sparked by a once-in-a-lifetime storm over the Christmas weekend. On Tuesday, the American airline grounded more than 2,600 flights on the East Coast. Those flights made up more than 80 per cent of all cancelled flights across the country. The airline then cancelled another 2,500 fights scheduled for Wednesday and 1,400 for the following day. Unions representing Southwest pilots and flight attendants blamed outdated crew-scheduling …
