Henry was stifling in his wealthy bourgeois milieu;In 1914,and we would feel the Union Sacrée (united front presented by the French against the enemy in 1914) when ,Learning that the war was declared,the characters broke into "La Marseillaise".Many French thought that the war would be short and they would take over the Alsace and the Lorraine . Those who were not drafted ,enlisted en Masse. Such was Henry's case.But he was declared unfit for service (on health grounds :TB)and it was a supreme humiliation ,considering the zeitgeist. So he decided he would be a fight pilot .He was so brilliant an aviator that he was finally enlisted in the Air force.