After studies in classical literature at the Salesian Institute in Faenza, at age sixteen he entered the Royal Naval Academy of Livorno; from 30 October 1916 to 15 July 1917 he served as an officer cadet on the training ship Flavio Gioia.

From 23 December 1921 to 20 August 1922 he served at the G. Fieschi seaplane base in La Spezia, then he returned to the Naval Academy to attend the higher course, at the end of which he was again assigned on the battleship Conte di Cavour.

On 28 November 1925 he was admitted to participate in the 1st Higher Course of the Regia Aeronautica, leaving it on 15 June 1924 with the rank of captain to take command of the Passignano sul Trasimeno flying school.

After the flying cruises to the Americas, General Francesco De Pinedo wanted him as his flight attendant at the Command of the 3rd Territorial Air Zone.

The command of the Regia Aeronautica entrusted him with the task of elaborating the doctrines and tactics of use for launching torpedoes from aircraft, and between 1933 and 1934 he carried out a long series of tests with the Macchi M.24 seaplanes and SIAI-Marchetti S.55.

During 1934 he was promoted to lieutenant colonel, and on the following year he published in the Aeronautical Magazine a long article on the experiences he had made and on the results obtained from his experimental work.

On July 28, 1936, ten days after the start of the Spanish Civil War, the Chief of Staff of the Regia Aeronautica, General Giuseppe Valle, entrusted him with the task of delivering twelve Savoia-Marchetti S.M.81 Pipistrello bombers to the Nationalist air force.

During his activity he maintained daily contacts with the highest military and civil authorities, carrying out inspections in Libya and Sicily, and on 31 December 1941 he was appointed commander of the Air Force of Tripolitania.

On 5 January 1943 he was repatriated for a short period of convalescence, but he never returned to Libya, as on 6 February he assumed command of the Auxiliary Aviation of the Navy (MARINAVIA), taking over from General Alberto Briganti.

Near the second half of October 1943, the Undersecretariat of State for the Air Force began to move from Rome to Bassano del Grappa, and Bonomi effectively became a liaison officer with the command of Luftflotte 2 in Abano Terme.

On November 27, 1944, after tense talks with Marshal Rodolfo Graziani and Benito Mussolini, Bonomi agreed to take the place of Molfese as Undersecretary for the Air Force, and as a first decision he moved the seat of the Undersecretariat from Bellagio in Milan, appointing Lieutenant Colonel Giuseppe Baylon as new Chief of Staff of the A.N.R.. During his mandate he always tried to avoid the use of the units under his orders against Italian targets, and when at the beginning of April 1945 the situation precipitated with the advance of the Allied forces in Romagna and across he Tuscan-Emilian Apennine, the supreme command of the Italian Social Republic arranged the retreat of the military units towards the Valtellina.

Together with Graziani and Adjutant General Rosario Sorrentino, Bonomi left Milan for Menaggio, where Mussolini was staying, and then for Como, where the surviving RSI leaders were meeting.