It takes 6 minutes for a fighter jet to cross the whole of the longest possible stretch of Swiss territory. How many defense missiles for the price of one F35?
if your enemy is flying over your territory the bombs have already dropped, you need to intercept them at range and have some leeway on top because missiles aren't guaranteed to hit and you have to have time to decide to send a second wave of missiles
so you are (as a non-NATO-member) defending your territory by effectively moving combat to the area of the most powerful military alliance there is today (heck, even Germany, where the army is in a, uuuhm, "sorry" state still has an air force comparable in size to countries like Saudi Arabia (which are smaller, but spend excessively on military)).
The only possible attackers then are either NATO states (which are largely democratic and "civilized" so that the people wouldn't tolerate a surprise attack on another "white"-country) or some foes attacking NATO.
In both cases they are screwed anyway and unless they decide to attack NATO with an outside foe, I'd be glad to see some American made, Swiss-flown CAP over Europe (which, sincerely is the most likely outcome if Switzerland really is democratic and not just a safe haven for corrupt elites).