There exists a strong rationale for an energy management system onboard civil aircraft; this is based on a global move towards greater energy consciousness and more specific reasons relating to safety and efficiency in the airline industry. This paper considers the design of an interface for an energy management system. It reports the development of a number of display designs within the requirements and constraints of the flight deck context. Three designs are evaluated both with student participants and senior airline pilots. It was found that those displays with predictive information elements produced the most accurate decisions concerning aircraft energy states. Further investigation into the function of these predictive elements (within real-time flight scenarios) is required in order to evaluate their efficacy with the end-user group of airline pilots.