The Savoia-Marchetti 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.

A total of 170 bombers — Caproni Ca.133s and SM.81s — operated in the Ethiopian war in the two groups of 9 Wing, which was a cloned unit ("bis") of the original 9° that remained in Italy.

The situation only became stable in 1937 by virtue of Italian air supremacy and support, which was decisive against an extremely dangerous enemy in this difficult and wild terrain.

36 SM.81s remained in Ethiopia to provide support to Italian troops occupying the country, including transport and the airlifting of supplies.

Small arms fire was the main danger, as the missions were flown at low altitude, but the damage was normally insufficient to bring down the aircraft, even though they had no protective armour apart from having self-sealing fuel tanks.

On a mission dedicated to supporting General Francisco Franco and his "alzamiento" (uprising) against the Republican government at the start of the Spanish Civil War; 12 SM.81s under the guise of Spanish civilian ownership took off from Elmas, near Cagliari, to fly to Morocco carrying 63 non-uniformed troops led by Colonel Ivanoe Bonomi.

Trying to maintain tight formation despite the clouds was also fuel-costly, with non-linear flight, only nine aircraft managed to land at Melilla.

Being only 3% of the total fuel capacity, this was enough for just a few minutes of flight and meant that, with only a slightly stronger headwind, all of them would have been lost or forced to land in Algeria.

Franco's Spanish Army of Africa troops were fundamental to raising the fortunes of the alzamiento which had hitherto been mainly beaten by the Republican loyalists.

The threat of the SM.81s and their bombs, once reinforced by the Italian ship RM Morandini, were sufficient to keep the mainly Republican Spanish fleet at bay, which otherwise would have been able to prevent any Francoist convoy reaching Spain.

Sorties were increasingly flown at night after the arrival of Polikarpov I-15 and I-16s in Spain, at which point only seven of the original nine aircraft were still serviceable, having released 210 tonnes (230 tons) of bombs and contributed (together with Junkers Ju 52s) to 868 flights transporting Morocco's troops.

One of the later SM.81 models developed had two Isotta Fraschini Asso inline liquid cooled engines with 626 kW (840 hp).

S.81s were almost as fast as the C-47, and had a defensive weapon set, while the range and payload was almost equal, with only a slight inferiority on installed power and speed.

Production of the SM 81 at this point was: SIAI, 237; Piaggio, 60; Macchi, 76; CRDA, 36; Breda, 36; CMSA, 58; AerUmbra, 20; and Caproni, eight.

In 30 days, nine aircraft were shot down, 10 were destroyed on the ground, and 18 were badly damaged - two-thirds of the total; there were no replacements.

In North Africa and Italy, SM.81s were used more and more as night bombers, no longer assigned to anti-ship and day-light bombing after the first year of war.

After that battle, SM.81s were used to supply the North African forces with reinforcements and stores and to evacuate Tunisia, with 18 Wing alone transporting 28,000 men.

In Pantelleria and Lampedusa, SM.81s were the only Italian air cargo aircraft capable of operating due to the short runways.

These aircraft tried to help the trapped troops when the Soviets began the Stalingrad offensive, all these machines were lost in that battle.

The Transport Group Terracciano, commanded by Maggiore Egidio Pellizzari, was formed in Bergamo and transferred to Goslar, in Lower Saxony, Germany, in January 1944.

Administratively the Italians were subordinated to the ANR but operationally to the Luftwaffe under the German designation of "Transport Gruppe Italien 10".

The Terracciano operated over the Baltic States, Russia and Finland, evacuating wounded soldiers and carrying fresh troops to the front.