I might have posted this before, a company in England that makes composite substitutes for ebony and rosewood
https://www.rocklite.co.uk/Apparently made from wood fibers and some sort of resin matrix.
The fingerboards get raves from guitar makers, although I haven't tried one. They make blanks for pool/billiard cues, so I guess they could make blanks for flute making.
Carbon fiber would be hell on tools, I'm thinking, but it's light.
Has anyone ever experimented with making conical flutes by forming them around a mandrel, like a Clark whistle? Lots of guitar makers now use "double tops," which are two layers of spruce around a core of Dupont nomex honeycomb. Alleged to have an outstanding stiffness to weight ratio. I wonder if you could lay up layers of material around a mandrel and then drill it.
Possibly a very very dumb idea, I realize