Powders travel better than liquids. Just make sure the cap is screwed on tight. I generally take a small plastic bowl with me when traveling, so I have something to swirl my brush in. If I don't have enough room for the bowl, then I'll just use the lid. The little lids on the drinking glasses in hotel rooms are excellent for swirling mineral makeup also.
I bought the brush that has the empty container attached to the bottom to put powder in. I LOVE IT! I keep it in my truck for traveling, etc. I think I got it from Lumiere or Everday Minerals. I can't recall which one. It was about $15.