The sequence where Robert Downey, Jr. is seen hanging from a rope flying across the skies above Thailand, including a Buddhist temple, was done for real, with Downey performing the stunt himself after director Roger Spottiswoode had rejected doing it using such alternative techniques as blue screen or back projection.
According to Wikipedia, "PepsiCo wanted the filmmakers to use a fictional soda rather than show opium being refined at their abandoned factory. Therefore, the producers added a line about wondering if Pepsi knew what was going on."
Robert Downey, Jr. despised his experience making this film in Bangkok, Thailand, and has vowed never to return to the country ever again for as long as he lives.
Robert Downey, Jr. did the film for two reasons, for the big paycheck and because he wanted to work with Mel Gibson, whom he had seen in Lethal Weapon 2 (1989) the previous year.
In the Special Edition DVD "Making of" documentary, there is a discussion as to how much of Air America's plot is true and how much is false. Some of the real-life pilots interviewed claim that Air America did smuggle guns and drugs for the CIA, while others deny it, saying that the service only shipped food, medicine, and supplies. However, a historian in the documentary asserts that only certain pilots were involved in the illegal activities. The characters of Gene and Billy are a perfect example of this. Gene, who is a bit crazy, cynical, and shady, has no problem getting involved in the illegal smuggling, so he, and pilots like him, would have been used for the real-life illegal smuggling. Whereas Billy, who is young, honest, and idealistic, would be used only for the straight supply drops, and would not be trusted for such illegal activities.