Toyota is adding to its stake in the so-called "flying car" start-up. Toyota Motor (TM 0.73%) is upping its investment in Joby Aviation (JOBY 25.10%), providing additional capital to support the air taxi start-up's push for certification and commercial production. Investors are taking the news as a vote of confidence, sending Joby shares up 21% at the open Wednesday and up 10% as of 10:15 a.m. ET. Cash from an important partner Joby is one of several companies racing to commercialize small electric aircraft ...