F-22’s and a double sonic boom? What is the mystery? Now if they were going Mach 3 then there is a story, but not necessarily one about alien tech.
Suddenly, sonic booms offend us.
Yeah, that's movin' a little fast. The engineering used to make the SR-71 *possible" to operate above Mach 3 was so complicated, it's not a wonder no one else ever reproduced it for manned flight. There has been a rumor that work is underway on something dubbed "SR-72", heh, trouble is, the missions carried out by the SR-71 are now done either from orbit or by drones, either way is cheaper and gathers more information at less risk.