In 1928 SISA took delivery of l-AABN, its first example of the three-engined CANT 22, powered by a trio of 200 h.p. Isotta-Fraschini Asso 200 six-cylinder inline engines in tractor configuration. Named San Marco in SISA service, l-AABN was later absorbed into the state-owned Societa Aerea Mediterranea and ultimately, Ala Littoria.
CANT 22 I-ALFA (c/n 230) was named San Sergio in SISA service and joined the company in June 1931. An unequal-span biplane with a single-step wooden hull and single fin and rudder, the type was fitted with two side-by-side cockpits situated midway between the wings and the bow.