This little eVTOL maker still has a lot to prove before its stock can take off.Joby Aviation (JOBY 6.36%), a developer of electric vertical takeoff and landing (eVTOL) aircraft, hasn't impressed many investors since its public debut. It went public by merging with a special purpose acquisition company (SPAC) on Aug. 10, 2021, and the combined company's stock opened at $10.62. But today, it trades at about $8.Joby disappointed its investors by missing its own estimates. It also faced stiff competition from o ...