Is Joby poised to be the early winner in the flying taxi market? One high-profile financial firm thinks so.Joby Aviation (JOBY 12.83%) stock posted big gains in Tuesday's trading. The flying-taxi specialist's share price ended the daily trading session up 12.8%. Meanwhile, the S&P 500 (^GSPC 0.40%)and the Nasdaq Composite (^DJI -0.28%) index closed out the day's trading up 0.4% and 0.28%, respectively.Joby's valuation climbed today after Needham initiated coverage on the stock with a buy rating and a one-ye ...