He obtained his fighter pilot's licence in 1917 and finished World War I with six aerial victories. He joined the Pierre-Georges Latécoère's Lignes Aériennes Latécoère company (later to become Aéropostale) in 1923, rubbing shoulders with, among others, Didier Daurat, Jean Mermoz, Henri Guillaumet and Antoine de Saint-Exupéry.
After Mermoz and Guillaumet, he was the third pilot to cross the Andes, eventually doing so more than 150 times. When Guillaumet disappeared in the Andes, Deley was one of the pilots who searched for him before he was eventually rescued.
He died and was buried in his home town of Marseillan.
Marseillan author, René Angel, has written a biography: Pierre Deley, pionnier de l'Aéropostale. (Editions Loubatières 2004)
- Biography on the Latécoère site. (in French)