While Schleicher was at Munich on motorcycle development and the competition side of BMW motor car activity, Fiedler was at Eisenach in overall command of the car side of BMW, specialising in chassis, suspension and aerodynamic design and development. His last automotive design from Eisenach was the 3.5-litre 6 cylinder BMW 335 saloon, a fine 90 mph car for the German autobahns. During the war he was occupied with military vehicle design and development and finished up at Munich, so that after the war he was in the American zone. During the war he was a Director of BMW, but left the board in 1945.