He then underwent pilot training, and beginning in June 1916, flew as an enlisted pilot of two seater aircraft for
Flieger-Abteilung (Flier Detachment) 51 on the
Eastern Front against the Russians. In August, he received the
Iron Cross Second Class and was promoted to
Unteroffizier. There was a four month lapse. Then, on 3 January 1918, he scored for the third time, and continued his success through until March, with his ninth victory on 26 March. On 3 June, he received the First Class Iron Cross. At the same time, he was awarded the Prussian
Military Merit Cross, the highest award for valor available to enlisted men in the German military. On 1 July, he downed his tenth victim to become a double ace. From that point on, he accrued victories until 4 September 1918, when he shot down three
Sopwith Camels from
No. 70 Squadron RAF Fruhner was subsequently
commissioned a
Leutnant. He was also proposed for the
Pour le Mérite, the German military's highest award for bravery by officers. There were only five German aces who won both awards. However, the Kaiser abdicated before approving the award. On 20 September 1918, while in a dogfight with Sopwith Camels of
No. 203 Squadron RAF, he collided with one of them. Although injured, he leapt from his irreparably damaged aircraft and parachuted to safety. The Camel he had collided with also crashed; it was credited as Fruhner's 27th victory. After this, Fruhner was withdrawn from combat duty. ==Post World War I service==