Factual error: Near the end of the film Knox is flying a Huey helicopter and the Angels hitch a ride by shooting it with a spear gun and dangling on the line behind it. Suddenly adding about 200kgs to a Huey in flight like that is going to cause all sorts of problems with the trim and airspeed of the aircraft - the pilot would know immediately that something was wrong. (01:23:20)
Audio problem: In the sequence where Natalie is saving Bosley and calling Pete, listen carefully. When Bosley warns her that there are thugs behind her, he says Dylan instead of Natalie.
Suggested correction: I just watched the movie...he says Natalie.
Suggested correction: Knox wasn't a trained pilot. Either he had no clue to what was going on, or he thought something may have been wrong, but didn't know what to do about it.
Taking off and landing a helicopter are by far the most intense and difficult part of a pilot's training. Seriously, 99% of learning to fly is learning how to land and take off. If the pilot is skilled enough to take off in a Huey he is easily skilled enough to notice a massive additional drag on his helicopter due to the additional weight of the angels and the air resistance put up by such a bulky protrusion on his aircraft. If he isn't skilled enough to notice that, he isn't skilled enough to take off in the first place.