[masraum]

Originally Posted by MRM

Sadly, as with Hotel California, we haven't had that spirit here since 1969. Humans haven't even attempted to increase the speed record in half a century. The X-Plane program and the narrow window of time in which they flourished will remain a lost golden age. So it is good to remember those more innocent and hopeful times and honor those magnificent machines and the people who made them possible.

One of the videos (don't remember which) actually did address that some. It was just too darned dangerous to push the speed envelope with a man inside.

But!!!

https://www.nasa.gov/multimedia/imagegallery/image_feature_231.html

NASA's X-43A research vehicle has screamed into the record books, demonstrating an air-breathing engine can fly at nearly 10 times the speed of sound. Preliminary data from the scramjet-powered research vehicle show its revolutionary engine worked successfully at approximately Mach 10, nearly 7000 mph, as it flew at an altitude of approximately 110,000 feet on November 16, 2004.