I bet it's common for military men/women to travel with body armor. It wasn't long ago that it was very common for families to buy kevlar/plate and send it to their young enlisted kids deployed abroad. Maybe the govt is now better about getting kevlar for every soldier and that doesn't happen as much, I don't know. Anyway, when those soldiers come back on a commercial flight they are bringing their personally owned body armor with them.Actually, as of today the TSA officially allows body armor in all baggage
Personally, I put my bp/w in a checked bag when flying. It's heavy, and I don't want to haul it around. It hasn't been lost yet, and my bags have had the "you've been searched" paper in them on occasion. If it does get gone, I'll rent a bcd for the duration of the trip. Regs and masks go in my carry-on.
If you want to wear your backplate, then why not put it in a carryon to get through TSA? After TSA but before you board the plane, take it out and put it on.