Consumer note: this movie suffers from a "why should I care" problem. As near as I can tell, the answer is: you should care because it's Denzel Washington.
Denzel plays airline pilot Whip Whitaker, and he's a mess. He's overly fond of nicotine, cocaine, and ethanol in its many commercial forms. His ex-wife and son despise him, pretty clearly due to his irresponsibility and dishonesty. But he's a darned fine pilot, as the movie demonstrates early on: when his routine flight from Orlando to Atlanta develops a catastrophic failure, Captain Whip ekes out a nasty, but survivable, crash landing, whereas most pilots would have left a smoking crater in the ground.
But the entire rest of the movie is about Whip trying to avoid going to jail, because the routine post-accident blood sample contained more booze and drugs than it had hemoglobin. As far as the world is concerned, he's a huge hero, but a growing number of people discover he's actually a devious lying asshole. Bruce Greenwood (Captain Pike!) and Don Cheadle, as a union rep and Whip's lawyer, respectively, turn in pretty good performances as Whip's semi-willing colleagues in his efforts to hide his problem.
It's nominated for two Oscars, Best Actor for Mr. Washington, one for the screenplay. The one for Mr. Washington—I think that's just a reflex action by nominators whenever they see his name on a ballot. Denzel? Check! Usually that's not a bad move, but here: eh.