This thesis investigates the experimental assessment of a hybrid propulsion system for unmanned aerial vehicles (UAVs), combining hydrogen fuel cells with batteries. The motivation arises from the growing demand for sustainable aerial propulsion solutions capable of extending flight endurance while minimizing environmental impact. Fuel cells, characterized by high efficiency and zero local emissions, are presented in the first part of the work through a theoretical overview of their operating principles and a review of their applicability in the drone sector. Particular emphasis is placed on the benefits and challenges associated with hybrid configurations, where batteries support dynamic load variations while fuel cells provide continuous power.