There were passenger planes before Germany's Junkers Ju 52/3 trimotor, but she sure is elegant.  The Junkers Ju 52/3 played an important role for Germany during World War II, serving as a troop transport and transport for her paratroopers.  The Junkers Ju 52/3 is famous for her corrugated metal flanks, but Junkers had been building such airplanes for years, starting with planes such as the all metal Junkers D.1 of World War I.