Which agency must be notified for armed law enforcement officers to travel on flights?

The correct answer is the Federal Air Marshal Service. This agency is responsible for ensuring the safety of air travel and coordinating the presence of armed law enforcement officers on flights. When armed officers travel on commercial flights, it is a security protocol that necessitates prior notification to the Federal Air Marshal Service, which helps maintain safety standards and enables effective coordination with flight and airport security.

This requirement allows the agency to manage potential security implications that may arise from having armed law enforcement officers on board. They can provide guidance and ensure all necessary procedures are followed, thereby enhancing overall aviation security.

The other agencies mentioned, while involved in various aspects of law enforcement and security, do not specifically handle the notification or coordination necessary for armed officers traveling on flights. The Transportation Security Administration (TSA), for instance, focuses on a broader range of airport and flight security measures rather than specific arrangements for law enforcement personnel.