Ruffo di Calabria returned to military duty before Italy's entry into World War I, and was assigned to the "Battaglione Aviatori" (which later became the "Corpo Aeronautico Militare") on 20 December 1914. After pilot's training, on 28 September 1915, he was posted to the "4a Squadriglia Artiglia", an artillery coordination unit that later morphed into "44a Squadriglia". On 26 January 1916, he moved to "2a Squadriglia" (later "42a Squadriglia"). He won two Bronze awards of the Medal for Military Valor—in February and April 1916—while still a two-seater pilot with them. His personal emblem was a black skull and crossbones painted on the fuselage of his plane, whether it was his original Nieuport 11s, or his later Nieuport 17 and SPAD VII airplanes.