Originally Posted by catocony

When you say "Military on duty", what are you referring to? Are you talking about back after 9/11 when there were National Guardsmen at some airports? Even then, they were not locked and loaded, and I'm pretty sure that the National Guard is no longer permitted to work security at an airport checkpoint. I believe that was temporary legislation passed in a hurry after 9/11 that is gone. At least in practice, since I haven't seen a Guardsman at an airport since 2002. Active duty military and reservists were never allowed to work security at airports, due to the Posse Comitatus Act. National Guards, being state entities, could.

If you're referring to active-duty military traveling as passengers, they can't carry weapons into the "sterile area" or on a plane any more than I can.