I remember reading an explanation of the "bumble bees can't fly" thing. It shows how one can reach totally absurd conclusions by applying good data to the wrong type of system. In this case, a dynamic-wing system is treated as stationary-winged. What the calculations prove is that a bumble bee can't glide, not that it can't fly. Its wing surface area is not adequate to keep it airborne, but only if it doesn't flap its wings, which it does....