Starting this spring, Allegiant Airlines will fly twice a week from MidAmerica St. Louis Airport to the Florida Panhandle beach city of Destin. The discount carrier announced the seasonal route at a news conference this week at the airport in southwestern Illinois. Service to Destin-Fort Walton Beach Airport will run from June 2 to Sept. 4 and cost as little as $39 one way. This will be the fifth MidAmerica route for Allegiant, the only airline operating at the airport. It currently connects MidAmerica with Las Vegas and two other points in Florida: Orlando and Tampa. It begins twice-a-week flights to Punta Gorda, Florida, next month. Struggling MidAmerica has sat empty at times since opening in 1997, but St. Clair County Board Chairman Mark Kern says passenger numbers are now growing.