This paper explores the design spaces of a thin-haul and a regional aircraft with parallel hybrid electric propulsion architectures and an entry into service date of 2030. Notional technology reference aircraft models were developed for a 19- and a 50-passenger aircraft based on publicly available data on the Beechcraft 1900D and ATR 42-600, respectively. Advanced technology aircraft models were developed by infusing the reference aircraft models with a set of selected airframe and propulsion system technologies projected to reach maturity by2030. Matlab and NPSS-based parametric, physics-based models were created for the charge depleting parallel hybrid electric propulsion system architecture. Different modes of operation were identified and parametrized with a basket of design variables to investigate the feasibility and trade space for peak power shaving, climb power boosting, electric taxi, battery usage schedules, and in-flight battery recharge strategies. A design of experiments with thousands of data points was conducted for the 19- and 50-passenger electrified aircraft propulsion vision systems. The vision systems were sized for the same point and mission performance requirements as their conventional counterpart. Artificial Neural Network models were fit toa set of subsystem, system, and mission level metrics of interest. An extensive trade study was performed to identify the fuel burn, weight, and efficiency trends and sensitivities as a function of different modes of operation as well as the electric powertrain key performance parameters and technology projections for 2030 and onward. The resulting multidisciplinary design space exploration environment was used to identify the optimum vision system designs and modes of operation for the minimum block fuel burn objective. It was found that both vehicle classes with the charge depleting parallel hybrid electric architecture provided fuel burn benefits over their 2030 advanced technology counterparts under certain modes of operation.