Some 23 S.66s were
built. It was basically an enhancement of the earlier
S.55, and re-
tained the unique
three-engined twin boom layout.. Initial customers were
Italiano and SAM.
These passed to Ala Littoria in 1934 upon the formation of that
from a John Player & Sons
cigarette card (circa 1938) of the
appears below. Many S.66s were still going
strong at the outbreak of WW II.