“Hopefully this leads to reduced travel times around the world that have not been improved for almost 40 years.”
The eventual spin-offs could possibly lead to reduced travel times for humans but the first application will be for high-speed kinetic kill missiles.
The main issue is that you have to be flying pretty fast to light off a scramjet engine, hence the launch from a flying aircraft. It takes lots of fuel to get an airframe flying at high enough speeds to kick off the scramjet, so there are inherent problems which have to be resolved before you could have an airplane with this technology.
It’s a challenge to get any vehicle flying at those speeds, since there are issues of heat due to air friction and the guidance and control issues are monumental, too. This is a big step toward some new technologies for the future.
I know we won't be going Mach 5 on United Airlines anytime soon, but the technology may help develop other technologies to increase current speeds.