[EN] In the new scenario where the transportation sector must be decarbonized to limit global warming, fuel cell-powered aerial vehicles have been selected as a strategic target application to compose part of the urban fleet to minimize road transport congestion and make goods and personal transportation fast and efficient. To address the necessity of clean and efficient urban air transport, this work consists of the conceptual development of a lightweight rotary-winged transport vehicle using a hydrogen-based fuel cell propulsion system and the optimization of its energy balance. For that purpose, the methods for integrating the coupled aerodynamic and propulsion system sizing and optimization was developed with the aim of designing concepts capable of carrying 0 (unmanned aerial vehicle - Design 1) and 1 (Aerotaxi - Design 2) passengers for a distance of 300 km at a cruise altitude of 500 m with a minimum climbing rate capability of 6 m s-1 at 1000 m. The results show how these designs with the desired performance specifications can be obtained with a vehicle mass ranging from 416 to 648 kg, depending on the application, and with specific range and endurance respectively within 46.2-47.8 km/kg and 20.4-21.3 min/kg for design 1 and 33.3-33.8 km/kg and 12.5-13.9 min/kg for design 2. This research has been partially funded by the Spanish Ministry of Science, Innovation, and University through the University Faculty Training (FPU) program (FPU19/00550) and FEDER and the Generalitat Valenciana, Consellerfa d'Innovacio, Universitats, Ciencia i Societat Digital through project IDIFEDER/2021/039. Funding for open access charge: CRUE-Universitat Politecnica de Valencia.