Hi Dear Peteroznewman,
I apologize for the delay in replying.Thank you very much for your guidance. I noticed that the two planes are not parallel and I have to cut the two sides of the shape a little.
But I still haven’t figured out how to convert the geometry STL file into a Solid wing with a Filled inside. I will be grateful if you teach me the process of doing this in the form of an educational video.