I have a 3D print of a spine bone from some animal, not sure, maybe a cow, but when you wing the bone around in the air in regular patterns, the spirals made up by all of the nooks and crannies on the bone seem to mesh right in with the spirals around which your fingers are constructed. This makes me think that bones would be great handles and also that they are shaped great for aerodynamicism, as long as that aerodynamicism is non linear.
So the first category is really for a bone handle, but I also would put this idea in the flapping flight category because a wobbling motor inside one with feathers duck taped to it would also make a drone.-- JesusHChrist, Dec 05 2016random, halfbakery