Air America was the CIA's private airline operating in Laos during the Vietnam War, running anything and everything from soldiers to foodstuffs for local villagers. After losing his pilot's license, Billy Covington is recruited into it, and ends up in the middle of a bunch of lunatic pilots, gun-running by his friend Gene Ryack, and opium smuggling by his own superiors.
Billy is a wacko pilot who loses his last straight job as a helicopter traffic reporter by getting into a screaming match with a driver. He takes a job working for what amounts to a CIA airline in Asia. Billy puts it as, "I'm used to being the weirdest person in the room. Here I don't even make the top ten." There is an insurgency shooting at them, government soldiers running drugs, a pilot who is supplying arms to the whole region, and those are the straightforward sub plots.