The field of man portable UAVs is currently a key area in improving the fielded warrior's capabilities. Pressurized aerostructures that can perform with results similar to solid structures could potentially change how this objective may be accomplished now and in the future. A flight dynamics simulation with reduced-order aeroelastic effects derived with Lagrangian and Eulerian dynamics approaches is developed and optimized to predict the behavior of inflatable flexible structures in small UAVs. The model also includes compensation for large buoyancy ratios and an investigation of the effects on different modes of forward flight. Existing literature documents the similarity in structural dynamics of rigid beams and inflatable beams before wrinkling. Thus, wing bending and torsional modes are approximated with the geometrically exact intrinsic beam equations using NATASHA (Nonlinear Aeroelastic Trim And Stability for HALE Aircraft) code. Some brief discussion also includes unique behaviors such as the onset of failure in the wing. An experimental glider platform is designed and flight tested. Data logged from these tests are used to support simulation model data. These results may later be used to specify recommended limits on flight maneuvers for inflatable UAVs.