18-Wheeler, I don't think it's a fair comparison.
The HyShot did not accelerate under its own power. It is merely an attempt to achieve combustion in supersonic flow, riding on a rocket.
The Russians have been doing this during the early 90's.
http://www.dfrc.nasa.gov/DTRS/1996/PDF/H-2115.pdf
Nothing really new there.
In the case of the X-43A, the vehicle was actually generating thrust, and flew autonomously.
--Machdiamond