History
This design element was used during the classical era of automobile styling. Opera windows saw their demise in the 1930s. Perhaps the most notable return was the "porthole" in the 1956-57 Ford Thunderbird. It was provided as an option to improve rear-quarter visibility with the removable hardtop in place. Opera windows were once again reintroduced on the 1972 Lincoln Continental Mark IV as an optional luxury feature, but it was almost universally ordered.
During the 1970s they became very common design elements of two-door hardtop or coupe models in all types of vehicles, from economy compacts to luxury brands. The windows were intended to offset the significant blind spots created by the very wide C-pillars that were characteristic of American cars produced at this time. In an age of decreasing dimensions and increasingly fixed rear windows on 2-door models, the small windows helped rear passengers to be somewhat less claustrophobic.
These windows were usually non-functional, however, in the case of the AMC Matador coupe NASCAR racers, the small windows in the Barcelona trim package actually helped to clean up the aerodynamics when such windows were open to the wind under racing conditions.
Opera windows had fallen into disuse by the mid-1980s, as changing automotive styles moved away from the more formal elegance that was popular in the seventies. The smaller and more aerodynamic cars made the opera window appear gaudy or out of place.
Contemporary examples of opera windows are sometimes found on overly decorated and tacky customized automobiles. They are now often regarded as one of the worst design innovations in automotive history.