Take a look at this tutorial for a Flying Lever Ghost. I love it because it does away with that complicated rig that gets tangled up too easy.
https://www.halloweenforum.com/tutorials-and-step-by-step/105274-building-flying-lever-ghost.html
https://www.halloweenforum.com/tutorials-and-step-by-step/105274-building-flying-lever-ghost.html