An aircraft propulsion system comprising: a single parallel propulsion unit positioned on a centerline of the aircraft, the single parallel propulsion unit comprising: a propulsor ; a gas turbine engine configured to drive the propulsor ; and an electrical machine selectively configurable to: generate, for output via one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor using electrical energy received via the one or more electrical busses ; and a plurality of series propulsion units positionally mirrored across the centerline of the aircraft, each of the series propulsion units comprising: a propulsor of a set of propulsors ; and an electrical machine selectively configurable to: generate, for output via the one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor of the set of propulsors using electrical energy received from the one or more electrical busses . a single parallel propulsion unit positioned on a centerline of the aircraft, the single parallel propulsion unit comprising: a propulsor ; a gas turbine engine configured to drive the propulsor ; and an electrical machine selectively configurable to: generate, for output via one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor using electrical energy received via the one or more electrical busses ; and a propulsor ; a gas turbine engine configured to drive the propulsor ; and an electrical machine selectively configurable to: generate, for output via one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor using electrical energy received via the one or more electrical busses ; and generate, for output via one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor using electrical energy received via the one or more electrical busses ; and a plurality of series propulsion units positionally mirrored across the centerline of the aircraft, each of the series propulsion units comprising: a propulsor of a set of propulsors ; and an electrical machine selectively configurable to: generate, for output via the one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor of the set of propulsors using electrical energy received from the one or more electrical busses . a propulsor of a set of propulsors ; and an electrical machine selectively configurable to: generate, for output via the one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor of the set of propulsors using electrical energy received from the one or more electrical busses . generate, for output via the one or more electrical busses , electrical energy using mechanical energy derived from the propulsor or the gas turbine engine; and drive the propulsor of the set of propulsors using electrical energy received from the one or more electrical busses . <EOS>