https://techcrunch.com/2022/02/08/momentus-founder-destinus-hypersonic-plane-29m-funding/

A new venture from space infrastructure company Momentus founder and former CEO Mikhail Kokorich aims to build a hypersonic aircraft for autonomous cargo delivery around the world. While the craft is far from completion, let alone testing and certification, a $29M seed round should help things along.

The stated plan is to build a hypersonic vehicle (i.e. multiples of the speed of sound) powered by liquid hydrogen and with only water as exhaust, which would enable point to point delivery nearly anywhere on the planet. Ambitious, yes, Expensive, yes. Difficult to engineer, also yes.