Following the end of Italy's campaigns in East Africa, a program was started to completely re-equip the Regia Aeronautica with a new interceptor fighter of modern design. They were interested planes powered with a radial engine, with 1-hour endurance, armed with a single 50-caliber machine gun. After realizing the armament was wholly inadequate, they later modified the specification to the also-inadequate two guns. Several companies responded with designs.
At Macchi the design started under the direction of Mario Castoldi, designer of the Macchi entries in the Schneider Trophy races, and thus a direct counterpart to R.J. Mitchell at Supermarine. His design was a completely modern all-metal cantilever low-wing monoplane with retractable landing gear and an enclosed cockpit. One interesting feature was the advanced design for the wing, the hydraulically actuated flaps were interconnected with the ailerons so that when the flaps were lowered the ailerons were drooped as well.
Power was provided by the 840hp Fiat A.74 radial engine, even though Castoldi preferred inlines and had used them in all of his previous designs. Italian industrial leaders had been instructed to concentrate solely on radials due to their better reliability, but this change may have set back the entire engine industry several years.
The first prototype C.200 flew the day before Christmas in 1937. It was followed by a second prototype early the next year. Testing of the prototypes went smoothly. One of them attained a speed of 500mph in a dive, although the puny engine drove the plane to only 315mph level. This was nevertheless better than the performance of the competing Fiat G.50, Reggiane R.2000 and Caproni Vizzola F/5, and in 1938 the C.200 won the competition and an initial order for 99 was placed. The G.50 was also placed in limited production because it could be in service earlier.
The C.200 began to enter into service in October 1939, by which time it had been given the name Saetta (Lightning). When Italy entered the war in June 1940, 144 had been delivered and some were in front-line squadrons. The first combat missions were flown as escorts for SM.79's attacking Malta in the autumn of 1940, and the type served subsequently in actions over Greece and Yugoslavia. The Saetta saw extensive use in North Africa and a number were involved in operations on the Eastern Front during 1941-2 where they racked up an impressive 88 to 15 score in that otherwise disastrous campaign.
Performance was never good enough. An attempt to solve this came in the form of a single prototype of the C.201 with the 1,000hp A.76 engine, but this was abandoned in favor of the Dailmer-Benz DB 601 powered C.202. The Saetta was to have been replaced outright by the C.202 after only one year in production, but the C.200's life was extended because Alfa Romeo couldn't produce enough of the RA.1000 (DB 601) engines, and more C.200's were built using C.202 parts while they waited for production to pick up.
In the end 1,153 Saetta's were produced, but almost all were gone by the time of the armistice in September 1943. Twenty-three were flown to Allied airfields in southern Italy, and flown for a short time by pilots of the Italian Co-Beligerent Air Force.