1941 Buick Fastback Coupe. This was a popular new GM body style introduced throughout the GM line in 1941. It continued in popularity after the war until Buick, Cadillac, and Oldsmobile introduced a new body style in mid-1949, the hardtop convertible. The last fastback Buick appeared in model year 1950. That year the Special series had both two-door and four-door versions.