[meow_catrix]

Those rotating things still produce their thrust by pushing a wing-shaped structure through air, producing a high-pressure zone on one side, and a low-pressure zone on another. That is what I was getting at. It is the same principle.

[trhway]

No, it is different. A prop or fan blade is inmovably attached to the shaft and pushed through the air the same way like the plane's wing, and the blade isn't flapped like the bird's wing.