High Quality Content by WIKIPEDIA articles! The Savoia-Marchetti SM.81 Pipistrello (Italian: 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.