In which decade did both automobile and air travel become popular and convenient

The correct answer is the 1920s. This was a period called the roaring twenties and that's when the economy started booming thanks to the development of the industry. Everyone now had a Ford car and airplanes became one of the favorite means of tranportation, and they were mostly safe. Unfortunately, this age was followed by the great depression in the 30s.

Ibelieve the answer is c