1937 registered a slight increase in the number of aircraft landings at Salzburg Airfield. In the summer the ÖLAG flew daily to and from Budapest-Vienna-Salzburg-Munich-Zürich.

This route was flown in a joint operation between the German Lufthansa and the Hungarian Malert with JU-52 aircraft. In addition to this a Junkers F-13 flight for commuter traffic between Salzburg-Innsbruck was introduced in June.

The historical events of the 12th March 1938, when Austria’s was no longer an independent state also saw new plans for the modernisation of the Salzburg Airfield by the authorities. There was a written plan for the extension of the existing landing field and the new construction of a large airport to the north west of it which touched the marked route of the Reichsmotorway. The model of a new large Salzburg Airport was shown to Hermann Göring on his visit in 1938. Lufthansa which flew the London-Brussels-Frankfurt-Munich-Vienna route with SABENA, made a forced landing in the summer of 1938 in Salzburg. The introduction of the Berlin-Prague-Salzburg-Venice and Munich- Salzburg-Klagenfurt-Ljubliana-Rijekaroutes were then planned for the summer schedule of 1939.

On 22nd of June 1939, the Salzburger Flughafengesellschaft was founded with 80% belonging to the Reichsluftfahrtministerium (the aviation ministry of the Third Reich) and 20% to the city of Salzburg. With the onset of war on the 1st September 1939, Salzburg Airport was seized and in 1943 the "Luftgaukommando VII" in Munich was put in charge of it. In the autumn of 1944 the newly developed fighter jet Me-262 appeared. When the American air force first bombed the city of Salzburg on the 16th October 1944 with a subsequent 15 air attacks on the city, the airport remained undamaged, in contrast to the inner city.

The Germans expanded the airfield by 80 hectares and 10/28 of the runway was concreted on top of this a large hangar near the Kugelhof and a small hangar next to the Karolinger woods were built. In addition, the facilities for flight safety and security were improved and the fuel storage enlarged to a capacity of 50.000 litres. During the final days of the war, Salzburg Airport was the assembly point for aircrafts of the leading officials of the NS-Party, Generals and Pilots. The list of different types of aircrafts extended from the Focke Wulff Condor-200, FW-190-D9, ME-109, Arado AR-96 and Fieseler Storch to mass- produced jets of the world - the Me 262. One of these 26 fighter jets Me 262 landed in a pile of gravel, away from the other fighter jets and was later dismantled by the Americans and transported to the USA. Salzburg Airport was officially taken over by the Americans on the 8th May 1945 with the surrender of the German Wehrmacht.