His rise to prominence was linked to his World War I experience of knowing both Hermann Göring and Bruno Loerzer.

Dahlmann served with ground forces until 25 July 1915, when he transferred to aviation for aerial observer training.

He would serve in aviation until war's end, being entrusted by Loerzer with the adjutant's duties for one of the world's first fighter wings, Jagdgeschwader III.

Dahlmann ended World War I as a decorated fighter ace credited with seven aerial victories.

By 1 August 1939, when Dahlmann transferred back to aviation by joining the Luftwaffe, he was the civil service equivalent of a colonel.

[3] Hermann Dahlmann joined the German Army by becoming an officer candidate, being appointed as a Fahnrich and platoon leader in the 82nd Infantry Regiment on 15 October 1913.

[4] On 21 May 1915, Dahlmann moved to the Replacement Machine Gun Battalion of the XI Armee Corps Kassel.

[7] The Fokker D.VIIs in use by both Dahlmann and Loerzer during September 1918 bore similar striking white and black patterns.

An abstract diving hawk was emblazoned in black on the white band circling the fuselage just behind the cockpit.

According to Dahlmann, Goering received the Pour le Merite on 2 June 1918 with only 18 victories because Loerzer lobbied the high command on Göring's behalf.

[12] After Dahlmann's duties as adjutant of JG III ended 19 November 1918, he was assigned back to FEA 3 at Gotha for demobilization.

His civil service employment saw him increasingly involved in aviation administration until the beginning of World War II.

He transferred to the Luftwaffe as the Department Chief of the Reichsluftfahrtministerium (Air Ministry) on 1 August 1939, thus placing himself under Göring's command.