Actually, even though Switzerland has technically been a neutral country in the past few centuries, their air force did actually fire its guns in anger numerous times during World War II. Granted, most of World War II they spent their time intercepting lone 'stragglers' (either Italian, German, American or British), but early in June 1940 there were a couple of serious incidents.
On the 4th of June 1940, there were a number of real dogfights between German and Swiss planes (1 Swiss C-35 vs. 1 German He-111 - indecisive; 2 Swiss Bf-109Es vs. 2 German Bf-110s - indecisive; 2 Swiss Bf-109Es vs. 3 German Bf-110s - indecisive; 2 Swiss Morane vs. 2 German Bf-110s - indecisive; 2 Swiss Bf-109Es vs. 2 German Bf-110s - one Swiss Bf-109E damaged; 3 Swiss Bf-109Es vs. 8 German Bf-110s - indecisive; 2 Swiss Bf-109Ds vs. 2 German Bf-109Es - 1 Swiss Bf-109D shot down, pilot killed).
Four days later, on the 8th of June 1940, there were further serious incidents, when the Germans deliberately issued a Freie Jagd mission over Swiss soil, which resulted in a number of dogfights (1 Swiss C-35 vs. 3 German Bf-110s - Swiss C-35 shot down, 2 crew killed; 12 Swiss Bf-109Es & 1 Swiss Bf-109D vs. 28 German Bf-110s - 1 Swiss Bf-109E shot down, 2 Swiss Bf-109Es damaged, 1 Swiss pilot severely injured, 3 German Bf-110 shot down and 1 damaged; 3 German crew killed, 3 German crew captured, 1 German pilot injured).
Of course, that all resulted in some diplomatic fracas between Switzerland and Nazi Germany, which was ultimately resolved.
Not to mention the time the RAF mistakenly hit Geneva, Renens, Basel and Zurich in 1940, or the occasions on which USAAF bombed Staffhausen (April 1st 1944, 50 B-24s, 40 Swiss civilians killed); Stein am Rhein (February 22nd 1945, 13 aircraft, 21 Swiss civilians killed); Zurich (March 4th 1945, 6 B-24s, 12 tons of HE & 12 tons of incendary dropped) or Basel (March 4th 1945, 3 B-24s, 12 tons of HE dropped); or the other mistaken USAAF attacks on Koblenz, Cornol, Niederweningen and Thayngen in 1944, and Chiasso (twice) and Brusio in 1945.