DULUTH, MN (KDAL) - The Duluth Airport Authority has announced that passenger traffic for the first quarter of 2013 was up by 5 percent over the same period last year. Duluth International Airport served 77,711 passengers in January, February and March. Most went through the new terminal building that opened on January 14th. Delta Airlines also announced an upgrade to their 5:30 a-m flight starting in June. A larger plane with dual class service and 76 seats will be used for that early morning flight and for other high volume days. Airport Executive Director Tom Werner says those positive changes will provide more seats and options for passengers heading into the peak travel season.