Yeah, high-pass filter does exactly what OP is looking for -- preserving high frequency details while removing low-frequency color variations. Here is how it looks if you combine the high-pass details with the average color of the original texture:
Scripting tends to give more direct and analog control, while animations are easier to deal with for complex motions (like a walk cycle or martial arts move). Airplane motions are simple and analog, so I would use scripting. You could set it up to have a hierarchy like:
- rudder pivot (empty)
- elevator left pivot (empty)
-- elevator left
- elevator right pivot (empty)
-- elevator right
And then you can just alter the rotation of the pivot objects as needed. It would also probably be possible to do it with animations by setting an additive blend layer for each movement, and combining them as needed, but I'm not as familiar with the workflow for that in Unity.