It has been over 3 years since the Transportation Security Administration (TSA) assumed responsibility for passenger and baggage screening at commercial airports. This testimony focuses on the progress TSA is making in strengthening aspects of aviation security and the challenges that remain. Particularly, this testimony highlights (1) progress TSA has made, and challenges it faces, in managing a federalized security workforce-including federal security directors (FSD) and transportation security officers (TSO)-with operational responsibility for ensuring security of passengers and their baggage; and (2) actions TSA has taken, and the challenges it faces, to ensure appropriate regulatory oversight of other airport security activities.