Having obtained a Civil Pilot's Brevet on 11 July 1914, Laplasse was soon transferred to the French Air Service. After serving with Escadrille 461CRP, he was reassigned to Spa75 on 20 October 1917, scoring his first victory by the end of that year. Before he was killed in action in 1918, he downed six balloons and one more enemy aircraft.
"Excellent pilot full of energy and spirit, has shown real qualities of audacity and courage in the course of numerous combats, strafing the German trenches and batteries at a low altitude, and returning often with his plane riddled by bullets." Médaille Militaire citation