On-board systems in fighter aircraft are expected to deliver high performance under extremeand hostile operational conditions. As technology advances, system architectures are shiftingfrom traditional federated configurations toward integrated and electrified designs characteristicof more electric aircraft. A range of architectural configurations, combining different powersources and consumers, can each fulfil the required system functionalities, offering distinctadvantages and drawbacks. To tackle this problem, energy and power management offers asolution-independent, agnostic framework for assessing on-board system architectural decisionswith respect to their impact on top-level aircraft requirements. Nonetheless, a clear understandingof the state-of-the-art and design sensitivities of these systems are needed in early stagesof design. This study describes on-board system architectures and their associated trade-offs toquantify and compare architectural options available to system designers. It reviews on-boardsystems from both federated and more electric aircraft architectures, linking them to the aircraftlevelfunctions they fulfill and outlining key design trade-offs. The systems reviewed includeflight control systems, hydraulic systems, fuel systems, electrical systems, pneumatic systems,environmental control systems, auxiliary power systems, emergency power systems, and landinggear systems. The review highlights that the interdependence and diversity of options of onboardsystems require robust integration frameworks that assess them collectively, rather than inisolation, to achieve a balanced architecture at the aircraft level.