Pre-impregnated composite material (prepreg) that can be cured/molded to form aerospace composite parts. The prepreg includes carbon reinforcing fibers and an uncured resin matrix. The resin matrix includes an epoxy component, polyethersulfone as a toughening agent, and a curing agent. The resin matrix is also composed of a thermoplastic particle component that includes hybrid polyamide particles wherein each hybrid particle contains a mixture of amorphous and semi-crystalline polyamide.