Clément Ader developed the Avion III, an experimental steam-powered airplane tested before military witnesses at Satory in October 1897. The device shows a state-backed, technically advanced attempt to achieve powered flight before 1903. The attribution of a successful flight remains disputed: the official War Ministry report stated it did not fly in a controlled manner, while Ader claimed years later to have covered 300 meters. This entry corrects the omission of Ader without granting him a priority the evidence does not support.