I view Passenger SSTs in the same bucket as Electrical powered airliners.

The companies in these spaces seem to excel in getting press via social and mainstream media. They have all kinds of snazzy computer renderings. Their time-horizons seem to always be around "five years to carrying passengers."

They are also woefully short on any kind of corporate pedigree for bringing aircraft to market. Beyond that, they always claim to be "this close" to making things work, yet they have very little actual no-kidding flying hardware to show for it.

I dunno. Maybe these companies will have some sort of breakthrough, and I'm just an old curmudgeonly non-believer. But when companies like Gulfstream have poured all kinds of R&D into SSTs over the years, but not pulled the trigger on a production aircraft, I think that tells you something.

Ten years from now, I don't think Aerion or Boom will have produced a single certified passenger aircraft.