Discuss what elements gave rise to President Roosevelt's idea that "the aviation will be important to grow the U.S. economy."
I think that the quote you are seeking is one in which President Roosevelt was able to establish what is now known as the Federal Aviation Authority. The exact quote comes from the act that helped to establish it, entitled the Civil Aeronautics Act in 1938:
[T]he [Civil Aeronautics] Authority shall consider the following ... as being in the public interest ... the encouragement and development of an air-transportation system properly adapted to the present and future needs of the foreign and domestic commerce of the United States, of the Postal Service, and of the national defense ... [and] the regulation of air commerce in such manner as to best promote its development and safety.
President Roosevelt understood that the advent of flight and the movement of it into an industry would be a realm where government intervention would be needed. He understood that in order to harness the full force and effect of the industry's impact on consumer life and the United States, some level of government oversight would be required. After much debate and discussion in committee as well as public hearings that enabled the President to see that regulation would help the nation's economic life and consumer foray into the realm of aviation, he signed the legislation in June of 1938.