A scramjet (100) includes a converging inlet (110), a combustor (120) configured to introduce a fuel stream (132) into an air stream in a combustion chamber (130) and to combust the fuel air mixture stream (134) to create an exhaust stream, and a diverging exit nozzle configured to accelerate the exhaust stream (136). The combustor includes a fuel injection system (150) including at least one arcjet (160). A method (300) of creating thrust for an aircraft (10) includes compressing (310) a supersonic incoming air stream (112) in a converging inlet (110), injecting (320) a fuel stream (132) into the air stream in a combustion chamber (130) to create a fuel air mixture stream (134), igniting (330) the fuel air mixture stream to create an exhaust stream, and exhausting (350) the exhaust stream from a diverging exit nozzle (220). The injecting the fuel stream into the air stream includes injecting the fuel stream at a fuel speed sufficient to create shear between the fuel stream and the air stream.