Cliffs of Dover is the Best. (A few screenshots).

[Les]

Hmmm...

Sorry if I'm missing the joke here, but if you go to external view when your plane is near another, you can zoom out and go into/through the other plane that's near yours. No setting of static camera's is required to see inside, though slowing down and pausing the game beforehand may be required if both planes aren't flying in the same direction.