Hell, they'll have half a billion just in the computing & control systems. Having worked to design, build, and certify the avionics systems on three major commercial aiframes, one of which is now flying (787), I am hopeful but beyond skeptical. When a company backed by the government of the world's largest economy (Comac) can't make decent progress on a subsonic airframe built with 20+ year old and well understood technologies, and when leading airframers like Boeing had a helluva tough learning curve building a composite subsonic airframer (787), I'm beyond doubtful that this startup is going to build a supersonic composite airplane before it goes bankrupt. Google '787 wing box' and '787 delamination' if you want to know the kind of pain Boeing went through when trying to build a composite airframe.

If you want to get and idea of the magnitude of the regulatory hurdles in a domain that most here will understand, google DO-178C. The mountains of documentation that you have to produce for the software will push any integrated avionics development effort well into the hundreds of millions, unless they plan on using bog standard off-the-shelf parts, and even then they'll have to deal with the flight control system, which will have to be custom by necessity. For some google food, search on 'wcet analysis', 'structural coverage analysis, 'MCDC analysis', 'requirements traceability', 'stack analysis', etc. There are huge hurdles to leap through to get certified, and that's just for the software.

I hate being a wet blanket :(.

OTOH, if they can get capital in the 5-10+ billion range, poach all the best folks from Boeing, Honeywell, Rockwell Collins, GE, UTC, Gulfstream, etc. etc. etc. (which will involve setting up offices in Seattle, Phoenix, Cedar Rapids, Cincinnati, Grand Rapids, Savannah, the UK, France, etc. -- the aviation scene is a bit older, people have families, and are not so keen to move), then they might actually pull it off. Which would be awesome. And I'd totally be in (if they set up an office in my area, that is).