[tsotha]

I don't see where this technology "fits". When you're going to orbit, 90% of the flight takes place outside the atmosphere, so an air-breathing engine doesn't do much for you.

For commercial sub-orbital hops, they'll have to bring the cost down considerably to compete with existing air service. Sure, we'd all love to be able to go from NYC to Frankfurt in an hour. But how many people will pay ten thousand dollars for the privilege?

[westicle]

Given that people already spend multiples of ten thousand dollars to fly it in greater comfort at "normal" speeds, I suspect there is already a significant market.

[tsotha]

The numbers are too small to justify a separate design. This is why Concorde failed.