The system-level capabilities and component-level sensitivities of hybrid-electric propulsion systems were analyzed by modeling a twin-engine general aviation aircraft. The flight performance model was developed using performance variables for the Tecnam P2006T found in published articles authored by the aircraft manufacturer. Both parallel and series hybrid-electric drivetrains were integrated into the aircraft performance model, and performance data were produced for various missions, degrees of electrification, battery specific energy densities, and electric motor power densities. The results quantified the improvements in battery specific energy density and electric motor power density necessary to make specific mission ranges feasible for several variants of each hybrid architecture. It was found that current technology allows a parallel hybrid configuration to achieve a maximum theoretical range of approximately 250 nmi. The results also indicated that parallel hybrid architectures will offer an effective near-term configuration, by offering greater range performance than a series hybrid with incremental future advancements in battery specific energy density and electric motor power density. However, distant future advancements in these technologies will allow series-hybrid architectures to produce similar range capabilities with improved fuel economy over parallel-hybrid architectures.