In addition to the Na'vi we also did some early design work on the human costuming as well to get the ball rolling. James favoured a very real world approach to the costume design which comes across so well in the final costuming. He would often reference the Vietnam war in terms of look for the soldiers and the level of gritty realism. For ground personnel the reflective stripes became a very practical feature that you could build a strong graphic identifier into. If you check out Aaron Beck's blog you can see more great Avatar costuming designs.