The mission performance and lifecycle CO 2 emissions of a simulated hybrid-electric regional transport aircraft were analyzed utilizing a flight performance simulation developed in MATLAB/Simulink. Publicly-available Embraer ERJ-175 data was used as a model to simulate a representative regional jet transport. After completing simulations to obtain the flight performance of a baseline, conventional regional jet aircraft, a parallel hybrid drivetrain was embedded into the model, and a series of flight performance simulation data were obtained for a representative hybrid-electric regional jet. Various missions with different degrees of hybridization and battery specific energy densities were simulated and the resulting range and fuel burn characteristics were compared to the conventional system. To investigate the potential for hybrid-electric aircraft to reduce aircraft CO 2 emissions, the CO 2 emissions from both fuel burn and production of battery energy were modeled for each hybrid aircraft configuration. The results indicate that dramatic reductions in CO 2 emissions per passenger mile are achievable when compared to conventional systems of equivalent range for all hybrid cases. However, only mid-future battery technology allowed for reductions in CO 2 emissions per passenger mile when compared to the maximum range conventional mission.