Ehrlich joined the army in May of 1913, and served with the infantry until his transfer to the French Air Service in December of 1916. He received a Pilot's Brevet in May of 1917 and was assigned to N154. Cited for actions against the enemy on August 10, 1917, he was badly wounded while strafing the German lines. Promoted to Sergent, he returned to duty in November of 1917. On the evening of September 18, 1918, three days after he was recommended for the Légion d'Honneur, Ehrlich was shot down and captured after scoring his 19th victory. The following day, his promotion to Sous Lieutenant was announced. In all, Ehrlich destroyed 18 balloons and shot down an Albatros scout in less than three months.

Médaille Militaire
"Remarkable pursuit pilot who has distinguished himself by his exceptional audacity and tenacity which have earned him twelve victories in one month. He flamed three balloons in a few minutes. One wound. Three citations." Médaille Militaire citation, September 10, 1918