First, I know the "Off Topic/Derail Team" is joking, but in all seriousness, NO. Do not attempt to board or enter an airport while wearing your armor. Airports are sensitive places these days, and have no time or patience for jokes or hijinks. You have no idea how other passengers or travelers or TSA or local law enforcement will respond. You could induce a panic by wearing a bulky, military themed outfit into one of the most sensitive places around these days.
When I fly with my armor I pack it into a rubbermaid tub that fits with in the “Checked baggage” limits without going into the “over-sized category.”
For most airlines this is a maximum size of 62 inches (length + width + height) per check piece of luggage. I drilled holes around the top of the tub and the sides to feed zip ties through to secure the armor. Zip ties are good becuase if TSA has to open the tub they just cut the zip tie and then replace it with their own zip ties. (The best thing to secure you luggage with in general is Zip Ties or TSA approved locks.)
The plastic tub is good becuase it provides a fair amount of rigidity and protection to your armor, but is also much lighter than most conventional hard shell suitcases. This is important becuase in addition to the size limits for over sized luggage, there is also usually a weight limit, somewhere around 50 pounds.
My armor is vacuum formed plastic, which means it is lightweight and therefore easily is under the 50 pound weight limit even when coupled with the tub and any extras I pack in with it. Also, becuase it is vacuum form plastic the pieces nest inside of each very easily, and compact down into the tub easily.
I also always place a document on top of the tub, so that if TSA opens it, it is right where they can see it right away. It lists my name, pone number, and what the costume is made out of, and shows pictures of the costume Front, Back, and Side.) Whenever I hand over the tub, either at the counter or to the TSA agents, I always also make sure to tell them their are replica costumes and non functioning prop weapons