There are all-natural thermal insulation materials out there. The Swiss company Fisolan AG is specialized in turning sheep wool into thermal insulation blankets ready to be used to insulate buildings … or commercial aircraft. Unlike glass wool the sheep wool blankets can be handled without health protection measures.
So that is how the Cockpit looked like before:
And after putting the sheep wool blankets:
Maybe a hint for aircraft manufacturers to plan their next zero-fossil-fuel aircraft with a natural insulation like sheep wool from Fisolan AG ?