Okay, what I was referring to is actually making sure that the engine start (hitting 'e') is recorded in the film, rather than be automatically started along with the film. For some reason that doesn't seem to get included in all cases. I messed around with camera shots once before and in order to get the sounds to be available I had to record the individual aircraft from the first instance of the film at least to the point that I wanted my clips to go to. Then I would edit the portions of the individual aircraft, or tank, from their own films.
If, I did like lyric just stated, then sounds would disappear.