Current challenges facing the aviation industry include energy needs and environmental pollution issues. One of the steps taken in recent years for the solution of energy and environmental problems around the world is the use of lithium-derived batteries. In line with the solution, it has been realized that a battery management system (BMS) is needed in addition to the batteries that have started to be used in the automotive and aviation sectors, due to misuse or damage from operating under harsh conditions. The battery management system (BMS) ensures that the battery's operating conditions are in an ideal range. A BMS must measure and check the voltage, temperature, current, state of charge (SOC), state of health (SOH) of the battery pack and battery cell when using lithium batteries. These measured values should be transmitted to the user by a communication method and records of the information should be kept. For these purposes, a hybrid battery management system (BMS) that can operate and control 12 serial lithium ion (Li-Ion) batteries and 12 serial lithium iron phosphate (LFP) batteries with two different features through separate ports has been designed for electric aircraft. With the new approach, Altium program was used for BMS design and LTC6804 microprocessor was chosen for cell measurements. Temperature, current, voltage, pressure and vibration sensors have been added to this microprocessor. The tests were done with program simulation. According to the simulation results, 0.326 Watts of thermal power was spent to balance the cells with approximately 90% accuracy in 3 different voltage measurements in two battery types. In line with these results, it was ensured that the two battery types could operate at different times by allowing switching between each other via the switching circuit. In addition, a hybrid BMS card design was created that enables the control and measurement of these batteries. (c) 2021 Elsevier Ltd. All rights reserved.