prototype first flew on 31 August 1940, at Ponte San Pietro with Caproni test pilot Ettore Wengi at the controls.

In 1941, Caproni Bergamaschi delivered the prototype to the Regia Aeronautica (Italian Royal Air Force), which began official tests at Guidonia Montecelio with good results.

The German Air Force (Luftwaffe) then requested control of the aircraft for trials at its test center at Rechlin in Germany.

Reasons given by various sources include a supposed overreliance on the use of materials in the Ca.331's construction that may have been in scarce supply (although this itself is controversial) in wartime Italy and Germany; the use of too many parts in the Ca.331, uncommon with other Italian aircraft (although it is not clear what specifically these may have been); political problems that Caproni company founder Gianni Caproni (1886–1957) may have had with the Italian Fascist government (which have not been identified clearly); an unwillingness of the Italian military to cooperate too closely with their German counterparts for fear of being dominated by Germany in the event of a German victory in World War II; or simply that the Ca.331 was under development for so long that the requirement for it disappeared before it could enter production, a common problem in the Italian aircraft industry during the World War II years.

prototype was at the Caproni company airfield at Taliedo at the time the Italian armistice with the Allies took effect on 8 September 1943.

prototype, it was at the Caproni company airfield at Taliedo when the Italian armistice with the Allies took effect on 8 September 1943, and it suffered the same fate: The Germans seized it there, disassembled it and shipped it to Germany.

prototype was constructed, differing from the first in having an armament of two 20-millimeter Ikaria cannon and four 12.7-millimeter Breda-SAFAT machine guns, all mounted in the nose.

It was still being assembled when Italy surrendered to the Allies on 8 September 1943, was seized by the Germans and shipped to Germany, destined never to fly.

[citation needed] Data from Italian Civil & Military Aircraft 1930-1945 [5]General characteristics Performance Armament