I still can't get over meeting a balloon pilot in white shirt with 4 stripes.....
Actually, you should wear what your boss/passengers want you to wear. If the airplane owner wants a uniform with stripes, so be it. If he doesn't mind you wearing jeans, fine... it's actually HIS call, just like it's the airlines or other companies who decide what their crews should wear.
As a private pilot I have worn an overall with sew-on emblems, but NEVER stripes!