1941 Buick Sedanette. The Sedanette or Fastback coupe was an early example of streamlining introduced by GM just prior to World War II. This fastback styling was very popular and continued to be offered by all GM makes after the war. Popularity only wamed after GM introduced the first production pillarless hardtops at Buick, Oldsmobile and Cadillac in the 1949 model year. Note the striking two-tone treatment offered by Buick on these cars, even extending on the hood of the car.