As a Swiss national Roques was assigned to the
Foreign Legion unit
2ème régiment étranger, with service number 36810. On 13 March 1916 he was transferred to the Army's aviation branch, the
Aeronautique Militaire, assigned to
1er régiment aviation and sent to the military flying school at
Chartres for his basic military flying training. He was awarded Military Pilot's Certificate No. 3495 on 26 May 1916 and was promoted to corporal the same day. He receivedadvanced flight training, including fighter tactics and aerial gunnery, at the military flying schools at
Avord,
Pau, and
Cazaux, completing his training in November 1916. After two months in a reserve unit Roques was posted to
Escadrille N.48 in early January 1917, based near
Verdun, to fly
Nieuport 17 fighters. From the beginning of April 1917, the escadrille began to replace its Nieuports with the
SPAD S.VII, and thus would eventually be redesignated
Escadrille SPA.48. Roques was promoted to sergeant on 25 April 1917, and gained his first aerial victory the following day, sharing in the shooting down of an
Albatros over
Loivre with Sergeant Robert Bajac. In mid-1917,
Escadrille SPA.48 were moved to the
Dunkirk area, and on 27 July Roques and Bajac, with
Jacques Ortoli of
Escadrille N.31, were credited with shooting down a Fokker two-seater over the forest of
Houthulst in Belgium. On 10 August 1917,
Adjudant Bajac was on patrol with Sergeants Roques and Hutteau when they spotted an apparently lone enemy aircraft, and despite orders to the contrary, Hutteau dove in to attack. However, the aircraft was the bait to a trap and the three French aircraft suddenly found themselves under attack by a group of Germans. Hutteau managed to escape and return to the French lines, despite having his aircraft riddled with bullets, while Bajac was wounded in the forearm and thigh, and lost consciousness briefly, recovering only from the ground, and managing an emergency landing on a road. Only Roques escaped unscathed. On 13 September 1917 Roques was awarded with the Belgian
Croix de guerre with palm, presented by
King Albert I at
Bergues, and in November he was promoted to
adjudant. On 19 February 1918
Sous-Lieutenant Bajac and
Adjudants Roques and Edmond Caillaux, now flying the
SPAD S.XIII, shot down a
Rumpler two-seater which crashed near
Nogent-l'Abbesse. Roques claimed shares in an enemy aircraft shot down on 17 May, and another two-seater downed on 11 June, but was not credited. However, on 12 June he and Bajac shot down a
Fokker D.VII over
Ressons-sur-Matz, and on 17 June he and
Sous-Lieutenant Gilbert de Guingand shared in the downing of a
Halberstadt CL.II over
Chaudun. On 9 September 1918, after having gained the five confirmed victories required to become a flying ace Roques was awarded the
Médaille Militaire. By the end of the war his
Croix de Guerre had three palms and the silver-gilt star (
étoile vermeil), and he also received the
Croix du combattant volontaire. ==Inter-war activities==