In the thesis work the effect of a regeneration phase during the descent of a small aircraft on the total mission energy requirement and the aircraft- and propeller design has been investigated. From the analysis it is found that to regenerate more energy, a steeper descent is required. However, during this steeper descent less ground distance is covered, hence to fly the same total distance a longer cruise is required. This longer cruise results in an increase in the overall energy consumption. Only when performing the exact same mission, with and without regeneration, the regenerative mode can save up to 2.9% mission energy of the analysed mission. Also it is found that the negative thrust that needs to be produced during the regenerative phase by the propeller can result in an increase in the solidity of the propeller up to 200%.