Interestingly, it appears BF42 does actually consider the geometry of the object, no matter what wings etc. you implement codewise.
Easy to test yourself. Just duplicate an object, but replace the geometries of one to another object and test their flight properties ingame.
E.g. compare a Bf109 and a B17, give them all the same rudders, wings and engines, and then test their flight properties. They should differ. The current consens over with the Battlegroup42 modders is apparently the engine calculates the drag real-time according to the collision mesh of the object. That means a huge, blocky object (e.g. a factory) flies worse than a regular slim fighter aircraft. Another reason why coding aircrafts is such a mess, even more if you only want to change details e.g. for balancing reasons...this really can be a pain in the as as I recently noticed myself once more...