The unit's roots date back to 1938, when Fliegerkompanie 20 was founded. On September 2, 1939, the military airfield Mollis became the home base of the unit. It had nine reconnaissance aircraft C-35s. In 1940 the Fl Kp 20 was upgraded to D-3800 Morane aircraft. In 1946, the Fliegerkompanie units were split up into pilots and ground crew groups, which resulted in the foundation of Fliegerstaffel 20. In 1948, the squadron got the P-51 Mustang, followed by the jet combat aircraft DH-100 Vampire in 1956. Only a year later, in 1957, the retraining to the aircraft type DH-112 Venom was completed . On August 27, 1962, the Fliegerstaffel 20 had a serious disaster. Three DH-112 Venom of the Fliegerstaffel 20 collided in the clouds near the Furka Pass, at the southern and nord Ridge of the Blauberg, when they tried to fly into the Rhone Valley in the course of maneuvers of the No 3 Swiss Mountain Corps.