Pitch is stabilized by the tail. When the nose points down, air hits the top of the tail and pushes the tail down, bringing the nose up. And when the nose is po

Pitch is stabilized by the tail. When the nose points down, air hits the top of the tail and pushes the tail down, bringing the nose up. And when the nose is pointing up, air hitting the bottom of the tail pushes the tail up. The V shape thing you mentioned for hang gliders is also true for most light planes. It’s a self stabilizing thing. I think what prevents th oscillation is that as it comes to level, the amount of upward force from the other wing equalizes.