Yes, it did happen.
During the battle for France, German aircraft intruded into Swiss airspace.
The Swiss had bought BF 109’s. Without radio etc, so they weren’t the latest things going around.
But they shot down Heinkels and BF 110’s (11 to 2) until Hitler and Goering threatened an invasion and they (the Swiss) decided not to take action unless fired upon.
Another bit of useless trivia.
Am I allowed to post links to other message boards? You’d probably really like this board, Historum, they are as good at History as people here are for scientific and legal questions.
A Mod can answer that question far better than I could. Thanks for the link, but it is pretty late at night here and I don’t feel like registering for any board. I’ll try tomorrow.
Thanks again.
They looked pretty spiffy with the Swiss livery too; many years ago I built a Bf-109G6 in Luftwaffe camo, including the swastikas, between some guy telling me that I could get in trouble with the Jewish community and another telling me that the best thing about the plane was the swastikas I made up my mind that if I ever make a new one is going to be in Swiss colours.
I think I should had clarified that I built a Bf-109G6 airmodel…
You could always try an Israeli Air Force version.
(Okay, technically, it was only the airframe from a Bf-109 in IAF service. The engines and props were from the He-111.)
There are rules against starting board wars (look at those assholes over there!). We do not require you to pretend the rest of the Internet doesn’t exist. I see nothing wrong with posting a link for a site someone may find interesting.
This is not an attempt to second guess a Mod’s judgement. I just want to say that considering Rule #34, I think that last sentence could have unintended consequences. 
There are other applicable rules.
Late in the war Switzerland acquaried 12 Bf109’s from Deutchland.
They immediately found the planes to be lemons and got half their payment back.
Along with 2 captured planes, they scrapped the 14 NEWEST Bf109 as lemons in 1947…
They kept the pre-war Bf109’s, good planes
More 109s were built than any other fighter aircraft in history.