Drone audio all sounds the same....sound of the drone. Roger uses music with most of his drone footage, rather than hear the props. This Whiplash footage has Dubbed train sounds. Not sure where the audio came from, perhaps another video camera and they used that audio. More likely its one piece of audio that's looped.
The best drone footage audio I have heard is when someone has another video camera trackside, that is far enough from the drone, that you don't hear the drone. Roger has done that, and the results are natural sound with the shots from the air. If there is enough audio to match the same amount of drone footage, or some extra, it is then easy to match whistles and everything else.
The point is the only way to get train audio out of drone footage is to have a long mic cable(maybe 200 feet), to get the mic far enough down to not hear the props, and to have the train audio cover up the props. Not many do that for safety reasons.
So to summarize, most audio with drone shots is dubbed in from elsewhere, its not from the drone system.
Greg