Motor cars are the symbol of the American dream and their design is a reflection of American society, which means that the 1970s had some serious problems.
The Space Age had much more fun with the automobile. Then cars were Yank tanks with steel breasts and were built so solid that the difference between them and light armour was a point of view. Engines were ever more powerful and speed seemed certain to hit the asymptote of the curve any day. Fins were everywhere and fins were king. This bit of prediction above by the Ford company is a perfect snapshot of the spirit of the times. The 21st century would be the era when cars would be jets with fins like scimitars and the speed limit would be the sound barrier.