Nieuport N.17 of the Schweizerische Fliegertruppe.
Airco DH.9A of the Schweizerische Fliegertruppe in the 1920s.
The Nieuport N.28 C-1 in the Schweizerische Fliegertruppe in 1918.
After WWI, the famous Fokker D.VII served in numerous air forces around the world. This particular aircraft was one of many that were used by Switzerland in the 1920s.
The De Havilland Canada Chipmunk was a post WWII training aircraft. Besides its use as a military trainer, it was also popular with civilian operators. The example below is a civil version registered in Switzerland.
Hawker Hunter as used by the Swiss Air Force during the 1960s.
Probably the most famous airliner of all time, the DC-3 was used world wide in both civilian and military service. From the D-Day airborne drops to the "Flying Elvises" in the movie "Honeymoon in Vegas", the DC-3 was there. After WWII, many airlines used the DC-3 including this example of Swissair from 1946.
The Bf-109E was exported to a number of nations before and during WWII. The Swiss Air Force was one of those nations and it used its Bf-109s to maintain its neutrality during the war.