2d paper plane movement

I want to make a little 2d game where the player controls a paper plane. The player can tilt it clock or counterclockwise. The plane should fly up and lose momentum when tilted up. The plane should fly down and gain speed when tilted down. I have tried it with a character in flying mode. The tilting part was easy, but I don’t get it working like I have described with the momentum. Any ideas how to archive this?