Ongoing work under NASA sponsorship is defining promising High Altitude Long Endurance (HALE) demonstration vehicle designs for remote sensing, communication relay, environmental monitoring, and other critical missions. Continuing challenges in preparing these vehicles for flight test include issues that will also be critical in the development of operational HALE vehicles: time-accurate simulation of aeroelastic effects; simulation-based design of flight control and propulsion systems for high efficiency, structural stability, and adequate control at all flight conditions; and effective, validated, full-vehicle dynamics analyses for aeroservoelastic applications. The proposed effort will address these needs by making available modular, state of the art modeling tools for use in full aircraft simulations to support vehicle assessment and control system design throughout the HALE flight test and development process. These tools will be operable in a range of modes with up to real-time turnaround and will feature a unique ability to support hardware-coupled ("hardware in the loop") simulation in conjunction with finite element-based aeroelastic modeling. This capability will support both near term flight demonstrations of prospective HALE vehicles and long-term design and analysis tasks for NASA HALE platforms.