Giannoti served as a volunteer in the Spanish Civil War. During his time in Spain he used the nom de guerre ”Vitullo”

When the Nationalist attack on the Basque Country began in the end of March 1937, I Gruppo was moved north and 3^a Squadriglia was stationed at Vitoria.
The 3^a Squadriglia was commanded by Capitano Mario Viola (”Viotti”) who led the 1st Flight of five aircraft (with reserve pilots) usually including Tenente Luigi Mariotti, Ottorinio Cappellini, Giannoti (”Vitullo”), Curilli, Sartori and Romagnoli.
The 2nd Flight was led by Tenente Corrado Ricci and usually included (with reserve pilots) Tenente Giuseppe Mollo, Sergente Maggiore Guido Presel, Sergente Maggiore Brunetto di Montegnacco, Eugenio Salvi, Aldo Galadini, Bernardino Serafini and Guido Pongiluppi.

In April 1937, XVI Gruppo ”Cucaracha” was formed and included 24^a (formerly 4^a), 25^a (formerly 5^a) and 26^a (formerly 2^a) Squadriglie.

Between 16:00-17:15 on 4 June 1937 on the Northern Front, ten CR.32s from 26^a Squadriglia, led by Capitano Mario Viola flying between Amorebieta and the Murguia front at 5 000 meters altitude, clashed with 17 I-15s between the Republican Escuadrilla Baquedano’s two bases (San Juan de Somorrostro and Sondica). Italian pilots claimed to have shot down seven “Curtiss fighters” in the Sondica area without loss, Capitano Viola being credited with two individual victories, Sergente Maggiore Guido Presel one Sergente Maggiore Guido Pongiluppi (CR.32 NC.128) one, Sergente Italo De Bernardinis one, Sergente Maggiore Aldo Galadini one and Giannoti one.
Although both sides drastically overestimated their claims, Spanish I-15 pilot Marcelino Alonso Romero from Escuadrilla Baquedano did indeed lose his life during this encounter.

Giannoti ended the war with 1 biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
1	04/06/37	16:00-17:15	1	I-15 (a)	Destroyed	Fiat CR.32		Sondica area	26a Squadriglia

Biplane victories: 1 destroyed.
TOTAL: 1 destroyed.
(a) 26^a Squadriglia claimed 7 I-15s without losses but only 1 can be verified (pilot KiA).

Sources:
Aerial War in Spain: Chronicle of air battle 1936-1939 – Sergey Abrosov, 2008
Guido Pongiluppi: Pilota Mantovano, Dal Cielo Di Campoformido A Quelli Di Spagna E Malta - Renato Zavattini and Antonio Inguscio, 2021 IBN Instituto Bibliografico Napoleone, ISBN 9788875655389