Germany, during WW2 - Repulsine by Viktor Schauberger, an alternative theoretic engine for planes and other flying objects. He stated: “As best demonstrated by Nature in the case of the aerofoil maple-seed, today’s propeller is a pressure-screw and therefore a braking screw, whose purpose is to allow the heavy maple-seed to fall parachute-like slowly towards the ground and to be carried away sideways by the wind in the process. No bird has such a whirling thing on its head, nor a fish on its tail. Only man made use of this natural brake-screw for forward propulsion. As the propeller rotates, so does the resistance rise by the square of the rotational velocity. This is also a sign that this supposed propulsive device is unnaturally constructed and therefore out of place.” (Viktor Schauberger, Implosion Magazine, No. 112, p. 52)
