The Mitsubishi Regional Jet , Japan's first commercial jet in half a century, will take to the air for the first time on Wednesday on a test flight, the aircraft's maker said. A successful flight at Nagoya Airport in central Japan on Wednesday morning will mark a major step forward for Mitsubishi Aircraft Corp, a unit of Mitsubishi Heavy Industries, in fulfilling a pledge to deliver the first MRJ in June 2017 to Japan's biggest carrier ANA Holdings.