Engineers Test a Jet Engine That Ran 70 Hours on Zero Fuel — Using Superheated Plasma Instead of Combustion A striking experimental claim has captured attention in the aviation and energy research world: engineers are testing jet engine concepts that operate without burning conventional fuel, instead relying on superheated plasma and electrical energy to generate thrust. The idea represents a radical departure from combustion-based aviation, aiming to eliminate fuel burn, emissions, and many mec