© 2015, American Institute of Aeronautics and Astronautics Inc. All Rights Reserved.The dynamics of flexible, swept flying wing (SFW) aircraft are described by a set of nonlinear, multi-disciplinary equations of motion. Aircraft structures are modeled using a geometrically-exact composite beam model which can, in general, capture large dynamic deformations and the interaction between rigid-body and elastic degrees-of-freedom. In addition, an implementation of the unsteady vortex-lattice method capable of handling arbitrary kinematics is used to capture the unsteady, three-dimensional flow-field around the aircraft as it deforms. Linearization of this coupled nonlinear description, which can in general be around a nonlinear equilibrium, is performed to yield linear time-invariant state-space models. Verification of aeroelastic stability analyses using these models is carried out. Subsequently, a set of SFW models are developed and the dynamic stability characteristics of these aircraft are investigated for a range of flight velocities and vehicle parameters.