Messerschmitt Bf.109D - Swiss users

Switzerland ordered 115 Bf.109D with the first 10 of then being delivered in 1938. When the Battle of France started, Swiss Bf.109D began to intercept German aircraft intruding their airspace. In fact, on 10th May 1940 many Swiss Bf.109D intercepted a German Dornier Do.17 close to the Swiss-German border in Bütschwil forcing the bombing to land near Altenrhein.
Late in the war, in 1944, they began to wear neutrality markings, the famous red and white bands on the fuselage.
The Bf.109Ds served together with the Bf.109E in various squadrons (Fliegerkompanie) of the Swiss Air Force until 1948 when them all, not just the Bf.109D but also the other variants that the Swiss Air Force had in inventory, were replaced by the much better North American P-51D Mustang.

Sources:
1. https://en.wikipedia.org/wiki/Messerschmitt_Bf_109_operational_history#Combat_service_with_Switzerland
2. https://en.wikipedia.org/wiki/History_of_the_Swiss_Air_Force
3. Salamander Books - The Complete Book of Fighters
4. Signal Squadron - Aircraft In action 44 - Messerschmitt Bf-109 in Action Pt.1