Plan a flight route that always flys the same directions on your compass. For example East. Then keep flying in that direction until you end up at your starting point.
The Earth is a flat disk (like the pizza pie) and the compass needle always points to the center (north). This being so, if you travel east or west you will eventually travel in a circle.
I noticed you avoided answering my question.
Can we at least agree that the n-body problem is hard science, if we are going to find any common ground to debate this ? Lets try to work backwards from there...
I don't see how it's possible to fly in a circle in a flat earth scenario unless you are turning at the same radius of the alleged disc.
EDIT: nomad13666 has been ignored, due to his repeated low-quality posts.