If you are going to burn the plastic anyway as jet fuel, you might as well burn it in furnaces, use anti pollution smokestack technology and save the cost of liquefying the plastic. The amount of carbon dioxide released will be about the same and maybe even less with modern capturing techniques.
Depends on what the heat of the furnace is being utilized for. Also, burning polyethylene produces a lot of black carbon soot.
Very good point. Very basic. But, does not fit Rube Goldberg ideology.
But then you won’t have made the jet fuel. I think the main thing they are excited about is making a liquid fuel.