Enhancing the performance of Flapping Wing Miniature Air Vehicles (MAVs) requires reducing the weight and total energy loss while increasing the efficiency. This thesis investigates an approach to reduce total energy loss through an energy harvesting technology, flexible solar cells. These cells are integrated with a flexible wing structure, to minimize the addition of weight to the MAV without comprising efficiency (i.e. performance). An optical technique is developed to characterize the effects of adding flexible solar cells to the shape of the flexible wing structure. A customized test stand for measuring lift and thrust assesses the effects of the solar cells on the flight performance of the MAV, both in stationary configuration (i.e. no air flow), and while subjected to air flow in a customized small-scale wind tunnel. The optical technique is combined with lift and thrust results to describe overall MAV flight performance. These results are then used in a theoretical analysis, developed for predicting time-in-flight, in order to perform a trade-off analysis.