A student and an irredentist volunteer with the nom de guerre ‘Paolo Testa’, he enlists as an automobile driver. Transferred to the 9th Fortress Artillery Regiment, he attends the Military School of Turin. After being sent first to the 3rd and then to the 2nd Mountain Artillery Regiment, he is nominated second lieutenant and assigned to the 58th Battery of the 2nd Mountain Artillery Regiment in Valsugana. In August 1917 he is promoted lieutenant and he attends the school for pilots, first in Foggia and then in Pisa. In April 1918 he is an aviator at the Foiano della Chiana airfield near Arezzo.