This disclosure describes at least embodiments of an aircraft monitoring system for an electric or hybrid airplane. The aircraft monitoring system can be constructed to enable the electric or hybrid aircraft to pass certification requirements relating to a safety risk analysis. The aircraft monitoring system can have different subsystems for monitoring and alerting of failures of components, such as a power source for powering an electric motor, of the electric or hybrid aircraft. The failures that pose a greater safety risk may be monitored and indicated by one or more subsystems without use of programmable components.