In the 1950s cars typically were constructed with a steel frame, chrome highlights (for example light hoods and body accents), wood trims and wool-blend upholstery.
However, there were some cars that strayed from this norm. For example, the Corvette was the first car made with a fiberglass body. Compared to steel, fiberglass bodies are lightweight and will not rust.
Other components were added to cars in the 1950s. These included seat belts, air conditioning and power steering. Plastic sheeting was also layered into windows to create safety plate glass.
Changes to cars in the 1950s were brought about to decrease the price of a car, increase safety, and make cars easier to drive.
In contrast, today's cars have a much higher percentage of plastic. Steel is still used in car frames, but bodies, accessories, and trims, are usually plastic.