Long-range and long flight duration unmanned aerial vehicles are essential for the Department of Defense and civilian operations to provide disaster response, humanitarian aid, and logistics missions. Our technical approach involves the implementation of high-energy liquid hydrogen storage and fuel cell power conversion on-board flight vehicles to extend the duration of flight by a factor of twenty greater than battery powered vehicles. Our comprehensive team of experts will be conducting a Phase 1 investigation into the feasibility of implementing of our liquid hydrogen technology from a total system approach including vehicle design, mission operations, and ground support refueling base operations involving the generation, transfer, storage, and consumption of liquid hydrogen. The NEOEx Systems, Inc. (NEOEx) EXTreme ENDurance EXTEND Energy and Power System will enable extremely long-duration/long-range operations for Unmanned Aerial Vehicles (UAV). Our UAV liquid hydrogen energy storage technology combined with fuel cell produced electrical power is scalable for commercial UAVs operating at less than 55 lbs. all the way to Personal Air Vehicles (PAV). The EXTEND System consists of a liquid hydrogen (LH2) Flight Storage System and a commercial-off-the-shelf (COTS) hydrogen fuel cell power system. EXTEND maximizes the amount of UAV on-board energy to provide flight duration up to 20 hours. Liquid hydrogen (specific energy of 2,000 Wh/kg), provides 20 times the energy per unit mass than standard lithium ion batteries (100 Wh/kg) currently used in most commercial UAVs. Energy in liquid hydrogen efficiently converts to electrical power by electrochemically combining hydrogen with oxygen from air using mature, TRL 9, COTS, fuel cell technology. Water is the only by-product, which is discharged overboard. Energy conversion efficiency of this approach >50%, compared to <20% for internal combustion engine approaches. Demonstrating the EXTEND Energy and Power System in Phase 2 on small Group 2 UAVs (<55 lbs) using the patented liquid hydrogen ground support equipment for refueling will have a profound and significant technical impact on the state-of-the art in UAV energy systems, that applies to a broad range of UAVs, PAVs, and Logistic Delivery Vehicles. Flight duration and range of a Group 2 UAV can be extended to over 20 hours and 1000 miles compared to one hour and 50 miles with the best lithium ion powered systems. Relatively silent operation, enables use in populated areas with minimal noise. EXTEND integrated Group 2 UAV platform is a low-cost/low-risk approach to achieving high-energy density on-board storage with full-scale refueling, extendable to all future liquid hydrogen UAVs.