I've flown with tincture bottles in the last couple months. Here's what I did. I put enough, that I needed for the flights and lay-overs, in the 2oz. bottles, made sure they had labels on them. I had the man print labels of what was in them at work, with ingredients and doses and kept it to 2 oz. Now it's says that you can only have 4, 3 oz. bottles so you keep it to what you absolutely need. Then, the rest that was underneath in cargo, I put shrink-wrapped bands on (which Uny was kind enough to send me several of each size so I could not worry about them leaking). It only took one conditioner bottle ten years ago, bursting, for me to put EVERYTHING in ziplocs that needs it. I separate things that if they were to leak - I couldn't then ingest. Like shampoo and conditioner? Those are fine in their own large ziplock but the tinctures? I bought a small, $5 zipping lunch pale that maintains it's shape (not collapsible) at a cheapy shop here. It was perfect. I shrink wrapped my bottles and put them back in the shrink wrapped sheets that Rocky works so hard to wrap all my bottles in. Then I stood them upright, with little ziplocs of IF2, cayenne and such, to keep them from further clinking together. Then I put a bit more bubble wrap on top, zipped it up and voila! No fear of my herbs being messed with. I packed the little lunch pale in the middle of my bag so that when they search luggage, they could open it up, see labels on everything and nothing would look strange and unusual.
Those lunch pales are awesome for this! Take a tincture bottle to a store with you - like Tuesday Morning, Target, dollar stores, etc, to make sure the rubber nipple has room to breathe and won't be too tall as to get squashed and you'll be so thrilled that you now have a little herb pale to go with you!!