For anybody out there with more money than brains, and who thinks they are going to make a killing selling business jets to rich executives (ie. the management of Adams, Safire, Eclipse, Spectrum, ATG, Sino-Swearingen, Diamond, Grob, etc.), just two words of advice: CASH FLOW. It will take you several YEARS to design, build, test, certify and put-into-production a certificated aircraft. And you will need enough free cash flow to support your business during this period, or you will go bankrupt.
The only VLJ start-up of the last few years, that has not gone belly-up (yet), is Eclipse. And they have burned through over half a billion dollars to date, and the product they have managed to delivered so far is sub-standard and likely to be recalled. The only reason Eclipse is even still in business is that they have some very wealthy individuals backing them. They claim to have orders for over 2600 aircraft at $1.4 million each, but they don't have the cash available to keep the company going day-to-day, while they build and deliver those 2600 aircraft.
Sadly, good engineers are usually poor business men.