Nowadays, the aeronautical field is transitioning from conventional fuel to electricity or hydrogen energy vectors. New environmental regulations constraining aircraft manufacturers push them towards new aircraft and powertrain architectures. These architectures largely differ from the current ones and require new design standards. All of the aircraft design stages are concerned. The research work presented in this article stems from a need of defining the influence of the Energy Management System on the early design stages. Previous work laid down the design basis. This paper showcases an energy management strategy associating powertrain and aircraft operation. Results over 5 flights highlight significant fuel savings as well as design discrepancies.