Answer:
The scientific and technological revolutions experienced in the 1920s United States paved the way for the development of modern cars and passenger air travel.
Step-by-step explanation:
While both the car and the airplane has been developed earlier, it wasn't until after the war, that the average person in the US began to buy cars. Famously, Ford's Model T was widely accepted with better safety features, comfort and better use of available technologies.
Similarly, the airplane was getting better every year but was only used for cargo or military use. However, with better technology, it became cheaper and faster to travel by air for everyone.
It can be said that these Post-war years set the stage for the transportation revolution in the United States.