Mostly fuel energy density vs battery energy density. You can use some biofuels (limonene) as a near-direct substitute for jet fuel though. I think maybe you n

Mostly fuel energy density vs battery energy density. You can use some biofuels (limonene) as a near-direct substitute for jet fuel though. I think maybe you need to change a few o-rings but the vapor pressure, combustion point, etc are all there and it's been demonstrated in Australia.