The symbols of nationhood

For some time I have been looking for the origin of a sometimes used quote about "flag" carriers. This from Time magazine in an article on 12 October 1970, reporting on Austrian Airlines and Swissair (since replaced by Swiss International after the latter made massive losses) is the earliest that I have found so far:

"Along with a flag and an anthem, the symbols of nationhood all too often include a money-losing national airline. Since 1950, the number of "flag" carriers has proliferated to the point that there are almost as many as there are countries in the U.N."

If anyone finds a similar earlier quote please let me know.