Vastly different fuels. Jet engines run on a Jet A1, kinda like diesel or kerosene, ignites under pressure with oxygen. Avgas is a high octane (100) petrol th

Vastly different fuels. Jet engines run on a Jet A1, kinda like diesel or kerosene, ignites under pressure with oxygen. Avgas is a high octane (100) petrol that requires a spark for ignition. Last time I was reading about unleaded avgas it seemed to be mostly a regulatory inertia problem, though I'm not well versed in aviation engine requirements.