The author explores a seemingly absurd idea: getting free traction in a stream of air or liquid. This seems to contradict the laws of conservation of energy and momentum. In fact, these laws are fully enforced. The peculiarity is that these laws apply to DIFFERENT masses. Everyone knows that you can get energy from a stream (wind turbines) and everyone knows that you can get thrust from energy (airplanes). The author examines the conditions under which the propeller thrust will be greater than the wind turbine resistance, i.e. we will get a positive thrust. This useful thrust can reach the value of the engine thrust during cruising flight, i.e. such a propeller aircraft will practically not consume fuel, can fly forever and will have an unlimited range. This is shown by the example of three propeller-driven aircraft: An-24 (medium passenger), An-22 (Antey, cargo), Tu-95 (military bomber). All that is required for this: slightly (0.2 – 0.5 m) increase the radius of the propeller and replace the propeller with an AB-propeller.