I don't even think it's that much of a problem of scale, it's much more a problem of when you are shooting where.
You can plaster their fuselage all day long from virtually any side (as has already been said), but as long as you don't score hits on the pilot, that is quite a useless effort. If you are however sitting directly astern, try shooting up the wing tanks in your convergence range. I usually bring down 2 out of 3 Heinkels doing that. The sweet spots are the wingroot and just outside the engine mounts.
Doing so will also greatly satisfy the "I want to see things go boom" type of player.
