Born from the same Regia Aeronautica requirement that spawned the Caproni-Vizzola F.5, FIAT G.50, Macchi C.200, Meridionali Ro 51 and Reggiane Re 2000 fighters, the A.U.T.18 flew for the first time on 22 April 1939, powered by a 1044 horsepower Fiat A.80 R.C.41 radial engine.