I'm trying my hand at doing my own modeling after all this time.
I'm trying to make a Tail Fin of a plane. I have a recess to put the Tail in but when I go to extrude the faces, I keep getting this plane appear which I can't select and only is on one side.
It also appeared when I extruded faces under it for engine piece.
Forget it! I solved it myself. The whole thing was being drawn upside down.
Time to get new glasses I think.. lol