Just a thumbnail analysis, but here goes:

From 1903 to the mid 1950s we went from the Wright Flyer to the (commercial) 707 and many supersonic military craft. There were qualitative improvements in thrust, range, size, speed, aerodynmaic control, etc.

Since the mid 1950s I would argue that the improvemnets have been quantitative, but not qualitative (an A380 follows logically from a 707 but is not revolutionary).

The FAA was created in the mid 1950s as well. The supervision by gov't has made aviation much safer, but this has retarded progress.

The pilotless craft will never come unless we change our acceptable level of risk (and the regulatory oversight that follows from it).

I'm not promoting less safety--simply stating that TANSTAAFL.

WW