All Federal law enforcement officers must be in compliance with 14 CFR Part 108 of the Federal Aviation Regulations. These governing regulations place certain restrictions on both airlines and federal law enforcement officials. Under these regulations, law enforcement officers in official travel status who are required to report armed and immediately ready for duty are permitted to travel armed (weapon in their immediate control) on board a commercial aircraft. These are additional qualifying conditions for flying armed, including: agency firearms authorization based upon arrest authority, completion of a certified training course covering Federal Aviation Administration (FAA) guidelines and alcohol abstinence. Additionally, you must present proper credentials and complete required airline forms.
Doesn’t say a thing about when they board or how they conduct themselves when they do. That is what I was referring to.