The Fiat CR.42 Falco ("Hawk") was a single-seat sesquiplane fighter that served primarily in Italy's Regia Aeronautica before and during World War II. The aircraft was produced by Fiat Aviazione, and entered service, in smaller numbers, with the air forces of Belgium, Sweden and Hungary. With more than 1,800 built, it was the most widely produced Italian aircraft to take part in World War II. The Fiat CR.42 was the last of the Fiat biplane fighters to enter front line service, and represented the epitome of the type, along with the Gloster Gladiator
RAF Intelligence praised its exceptional manoeuvrability, further noting that "the plane was immensely strong", though it stood little chance against faster, more heavily armed monoplanes. It performed at its best with the Hungarian Air Force on the Eastern Front, where it had a kill to loss ratio of 12 to 1.
Source: Wikipedia, "Fiat CR.42", available under the CC-BY-SA License.