Do you know about the simple static cord? Read the article below
The static cord is a very good way to carry a fixed blade knife for optimal concealment. It provides easy access, but you can shove the entire knife down into your pants if necessary and nothing will be seen. This is how I carry my ceramic knife (will go through metal detector) when I travel internationally.
I had Matt from Zulu Bravo Kydex custom make a non-metallic sheath for the blade.