What regions of the united states still lacked air routes in 1930?

 The correct answer is : In the high plains there were still no aerial routes in 1930.

Explanation:   In the 1930s, the aviation industry was consolidated throughout the world. The plane became indispensable as a means of transport. In 1930 about 7350 aircraft were licensed to fly in the United States and about 15,000 pilots received their flight license.

the answer is migration