Player retains 1-block hitbox if entering a minecart while flying with elytra

If you use your elytra, your hitbox shrinks to be only one block tall. If you enter a minecart while you have this small hitbox, you stay "small", and your eye level is underneath the minecart. The same thing happens for boats. When they're on land, they make the player suffocate. In water, it fixes itself.