An aircraft propulsion system includes at least one hybrid-electric power plant for delivering power to an air mover for propelling an aircraft. The at least one hybrid-electric power plant includes a first thermal engine and an electrical motor arranged in a parallel drive configuration or in an in-line drive configuration. The aircraft propulsion system includes a second thermal engine operatively connected to the electrical motor to power the electrical motor. A method for providing propulsion to an aircraft includes delivering power to an air mover for propelling the aircraft with at least one hybrid-electric power plant. The at least one hybrid-electric power plant includes a first thermal engine and an electrical motor arranged in a parallel drive configuration or in an in-line drive configuration. The method includes powering the electrical motor with a second thermal engine.