The Rise and Fall of American Growth: The U.S. Standard of Living since the Civil War (The Princeton Economic History of the Western World Book 70)

by Robert J. Gordon

Even though nonstop service from Hawaii to the mainland had been achieved in 1935, and by 1948 Pan Am and United were each flying four daily flights on the route, there was a mysterious seven-year lag in developing an aircraft that could fly exactly the same distance from Los Angeles to New York.

Surely this is not a total mystery