ImbracableCrunk… on a weathervane, the rear part has the majority of the mass and the most arm from it's vertical axis so the wind acts on it, rotating it around it's axis until it lines up with the wind. If the wind sways a little sideways, it'll hit the rear part, bringing it back into line.
If while in level flight, you banked an airplane to the left 30degrees and added no up or down elevator and didn't add any power, would the plane still turn? Yes.