Paul Tomblin wrote:
In a previous article, "Montblack" said:
The Cri-Cri weighs half as much.

It does? That page you linked for the jet Cri-Cri says it weighs 170kg.
The Guiness certificate for Wan's BD5J says it weighs 162kg.

But the Cri Cri flies and it would take at least another 10 Kg of stuff
to get the juanatross off the ground. That would probably include a
better jet engine and a fly-by-wire system to overcome the instability.

Tony