I have listened to several oral history interviews with Air America pilots and they hate the movie for how it portrayed them but loved the flying scenes.
I don't think it likely that any knowingly flew drugs, but with guys like Tony Poe having such a free hand on the ground and how important drugs were as a cash crop to the Hmong, I have no doubt that a portion of those packages they flew contained illegal drugs. Their day was just hopping from dirt strip to dirt strip. People get on, people get off, cargo is shoved in, cargo is shoved out, all day every day.
The biggest takeaway for me from the interviews was that the Air America guys were not career CIA, certainly not spy types. They were almost universally guys who scored a good paying, exotic, an exciting job.
I think the writers of the movie tried to humorously capture the insanity that the war in Laos was. I don't think any one person ever really knew all that was going on there at any one time. I am not sure anyone does today.
You had a tripartite government at war with itself fighting a sideshow war by proxy for the US, USSR, China and both Vietnams. All who agreed to pretend that the country was neutral while it was the most bombed country the world has ever known. At one time in the capital of Laos, Vientiane you had CIA pilots drinking at a bar while the next table over sat Soviet pilots who delivered cargo to the opposite side and down the road NVA officers played volleyball in an R and R compound.