Interesting thought...
Does Kevlar (in a Flak Jacket) show-up on X-Ray machines???
Interesting question. For many years I carried arround a square foot of ballistic kevlar in one of my carry-on side compartments that had been well used in ballistic testing against all sorts of arms. Most of the bullets were still embedded in the kevlar. I finally decided that in this day and age that the simple discovery of it by some security inspector would raise more questions than I had time to answer trying to catch a flight, So I took it out of my carry on.
In the interests that this thread has gotten so broad in content I respectably decline to answer further questions about this in this thread.