> It works by pushing against the surrounding medium. Not really. If a fan was able to blow air in a vacuum it would produce thrust as well. Basically a rocket

> It works by pushing against the surrounding medium. Not really. If a fan was able to blow air in a vacuum it would produce thrust as well. Basically a rocket does that. It's just blowing gasses out the back. It's Newton's law of motion, "every action has an equal and opposite reaction".