Diners continued to develop their own look, jumping headlong into the art deco trend and streamlining. By the end of the 1930s, all surfaces and textures were brushed, polished, rounded, or wrapped. New materials, such as Formica, glass blocks, and stainless steel, further emphasized diners' machine-age efficiency, maximizing turnover and getting hot food to hungry patrons in a flash.

"Split-diner" construction was an amazing design innovation that led to the super-size diners of post-World War II America. Diners began to be built in several sections, which were split apart for shipping and re-erected on location. New rooflines, enlarged picture windows and curved glass corners became the hallmarks of the diners of the 1950s.