Yes, plans were drawn up...but Hitler never wanted to invade, especially after France fell and Operation Barbarossa began, and it was the correct strategic move for them. Had the Battle of Britain been won by the Nazis and the eventual land invasion successful, or had the Nazis never invaded Russia, Switzerland probably would have been invaded. But invading Switzlerand would have required their best mountain troops, which they needed for Russia and possibly Britain. Plus, like I said, Switzerland did a lot for the German wartime economy. And by 1941/1942, they had built very formidable mountain defenses.