Welcome to Hirt! The original Homebase of Diamond Aircrafts! Hirt Airfield (Flugplatz Hirt) is located near Friesach in a valley in central Carinthia, Austria. In 1981 Diamond Aircraft was orginially founded on this very airfield. This airfield welcomes you with scenic views and stunning flights from soft hills across the Carinthian lakes to the core of the alps within a few minutes.