TSA uses layers of security to ensure the traveling public and the nation's transportation systems are protected. TSA is most often associated with the airport checkpoints operated by transportation security officers. Checkpoints represent one layer of security among the many in place to protect the various forms of transportation. There are different measures of security utilized within the aviation system including intelligence gathering and analysis, cross-checking passenger manifests against watch lists, random canine team screening at airports, federal air marshals and federal flight deck officers that provide armed protection to the aircraft. There are also additional security measures undisclosed to the public.
Each layer serves as a counterterrorism measure. In combination, these layers provide enhanced security creating a much stronger and protected transportation system. TSA applies these layers of security to deter, detect and prevent an attack from happening.