Daredevil 'Mad' Mike Hughes died after his homemade rocket crashed on 22 February 2020. The cause appears to be the premature deployment of the parachute used for a safe return. He was hoping to reach 5000ft.
In the U.S., Title 14, Code of Federal Regulations, Subchapter F, Part 91.7 states:
"No person may operate an aircraft unless it is in an airworthy condition"
The FAA defines an aircraft as "A device that is used or intended to be used for flight in the air" and has extensive information on certifying home-built or experimental aircraft. The original rationale, I presume, being that an aircraft is a danger not only to its occupants but people on the ground too.
They also say
the owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition
... but what is not made clear is whether it is an offence to operate fly your own aircraft without FAA airworthiness certification.
With regard to Hughes' home-built rocket, the FAA definition of aircraft surely qualifies this device as an aircraft, (although, owing to its speed, not an ultralight which have their own waivers). Further, there was no intent or pretence to go to space, so the SpaceX / NASA rules don't seem to apply here.
It seems to carry no registration, nor the mandated "EXPERIMENTAL" marking one would expect if it were - however, it is noted that in the US an aircraft does not have to be registered to be certified airworthy (although they usually are).
Should this sort of aircraft fly with an airworthiness certification? And if it didn't, why not?
NOTE - this is neither the place nor the time for a discussion of the wisdom of Mr Hughes' venture.