Frontier Airlines continued to add to its schedule of flights out of Milwaukee with a new seasonal nonstop to Tucson, Ariz.The once-weekly Saturday flight between General Mitchell International Airport and Tucson International Airport will launch Jan. 8 and operate through April 16, 2011. Frontier also offers twice daily service between the two cities that connect at Frontier’s Denver hub.Frontier, a unit of Indianapolis-based Republic Airways Holdings Inc. (NASDAQ: RJET), will use Embraer 190 aircraft. Daniel Shurz, vice president of strategy and planning for Frontier, said the flight will be the first-ever nonstop service from Milwaukee to Tucson.This nonstop service, combined with our two daily connecting flights out of Denver, allows our Milwaukee guests to easily fly south this winter and enjoy all that Tucson has to offer, Shurz said.Frontier is a sister carrier to Milwaukee-hubbed Midwest Airlines, another Republic subsidiary formerly based in Oak Creek. Frontier and Midwest are being merged into a single carrier under the Frontier name.