As you can see, in a flat turn, it's all yaw, no pitch; in a 90 degree banked turn, it would be all pitch, no yaw. Both the yawing moment and the pitching moment are produced by the natural weathercock stability of the airplane.
So according to this reference, the aircraft is basically moving around the axis that is in between the vertical and lateral axis?
Most references simplify with "the horizontal component of lift turns the aircraft" without going much further. That is simple enough for what is required by the FAA but I hardly find that satisfying.
Actually, I was very surprised to find how there is a lack of *detailed* information there is for the curious *layperson* on how an aircraft turns. If its not painful obvious, I'm not a engineer of the natural sciences. I am sure I have intellectually dragged the discussion down a notch with the number of engineers and those with experience here, but I am at least glad to participate and thankful for the help in understanding from everyone.