This thesis considers the application of L 1 adaptive control methodology to a model of the X-48B Blended Wing Body aircraft. We explicitly verify the performance bounds of the adaptive flight control system at various flight conditions. We demonstrate that the resulting L 1 adaptive controller does not require tuning or redesign from one flight condition to another. Furthermore, once designed according to the theoretical guidelines, the L 1 adaptive controller ensures uniform transient and steady-state performance across the entire flight envelope in the presence of significantly coupled dynamics and control surface failures.ii