HMM! I've been retired for 4 years, after having been a police officer for 31 years. I have YET to be informed that I am now a member of "Homeland Security" forces!
The President signed the "Police Officer's Bill of Rights" act, which gives both active-duty and honorably-retired police officers "reciprocity" for carrying firearms in all 50 states....but that does NOT cover carrying a firearm on an airliner, unless the officer has a REASON to do so and has attended training in "Flying while armed" courses.
For several years, prior to 9-11 and before the anti-gun folks started up with their ridiculous rhetoric, I flew on numerous commercial airliners while armed. All it took was to "declare" your desire to do so, and to have the approval of the pilot of the aircraft. On several flights to Hawaii, my "coach" ticket was up-graded to either First Class or sitting in the "jump seat" in front of First Class, as a "preferred" passenger! Back then, the "Air Marshall's" didn't exist on American airliners. The Israeli's have employed "Air Marshall's" for about 30 years....and their current status is that they are on ALL Israeli airliners.