Boeing ( BA) is the top-performing component of the Dow Jones Industrial Average so far in 2010. That's a welcome change from last year, when Seattle's aerospace giant lagged the venerable index and broad market, thanks to slow progress in the development and rollout of its state-of-the-art 787 Dreamliner.Of course, shock waves from the 2008 crash still rattle the stock, because it relies on healthy nations and air carriers to buy its expensive product line. That's a tough chore in 2010, despite the economic recovery, with potential buyers delaying purchases of big-ticket items and revitalizing airplanes that are 20, 30 and even 40 years old. However, the world needs to upgrade civilian and military fleets sooner or later, and Boeing will finally fill up its parched order books. Since the market is a future discounting mechanism, the current uptrend already reflects a piece of this upcoming growth. This raises the primary question of this column: Is it already too late for RealMoney readers to buy the stock?