The Savoia-Marchetti SM.81 Pipistrello ('Bat') was a three-engine bomber/transport aircraft serving in the Italian Regia Aeronautica during World War II. Despite being too slow to remain competitive as a bomber, it was one of the most flexible, reliable and important aircraft of the Regia Aeronautica from 1935-1944, and adapted to second-line duties in performing a wide range of tasks.
The SM.81 first saw combat during the Second Italo-Abyssinian War, where it showed itself to be versatile serving as a bomber, transport and reconnaissance aircraft. SM.81s also fought in the Spanish Civil War with the Aviazione Legionaria and were among the first aircraft sent by the fascist powers to aid Francisco Franco.
Despite their obsolescence, by 1940, when Italy became involved in World War II, more than 300 (290-304 depending on source) SM.81s were in service with the Regia Aeronautica. The first Italian aircraft to enter action in East Africa were a pair of SM.81s. On 11 June 1940, one of them attacked Port Sudan and the other flew a reconnaissance flight over the Red Sea. That same night, three SM.81s took off to bomb Aden, but one turned back, and one of the other two hit a hill near Massawa while trying to land.
Its low speed and vulnerability to fighter aircraft meant that during daytime it was restricted to second line duties, finding use as a transport. At night the SM.81 was an effective bomber, particularly in the North African theatre. Anti-ship actions were also carried out, but without significant success.
Most SM.81s were withdrawn by the time of the Italian armistice of 1943, though some remained in service with both the Italian Social Republic and the Italian Co-Belligerent Air Force.
