The Aircraft
When the Germans were bringing out the Bf-109, the British had the Hurricane and were bringing out the Spitfire, and the USA had the P-40 and P-39, Fiat introduced the last biplane fixed gear fighter produced in any large numbers. Although the Falco was pretty much outclassed in speed, it was structurally very strong and highly maneuverable. It remained in service through 1944.
The CR 42 remained in production through 1942, and participated in the Battle of Britain. They were used by the Luftwaffe on the Eastern Front and by Italy as night fighters, even though they had no radar or radio. While I’m still doing some research, apparently a Gladiator and CR 42 were in combat in December of 1940, probably the last biplane dogfight.