It’s saying a lot to declare that Washington gives one of the best performances of his career, but that’s just what the two-time Oscar winner does in “Flight.” The character of veteran pilot Whip Whitaker is a drunk and a womanizer who stumbles into heroism after preventing his plane full of passengers from crashing. But things are not always black and white, and Whitaker turns out to be a man full of contradictions. Washington portrays him flawlessly.