Which factor did not contribute to the increase of leisure travel in the early twentieth century in the united states? the mass production of automobiles the formation of the airline industry improvements in the railway system the development of online travel websites

The answer is D: the development of online travel websites

The correct answer is D.

The car, railway and airline industries were astonishingly developed during the first half of the 20th century. At first, only upper classes and richer citizens could pay the price to use these means of transport, but not much time later they became affordable for everybody and this is the main reason why leisure travel appeared.

On the other hand, internet  was invented in the 1970s and it was not massively used in households until the 1990s and 2000s. Online travel websites date back from even later.

answer: president kennedy is vowing to protect freedom in this paragraph.