I'll probably end up getting my vet to prescription sticker the Nutrical, or I'll put a tiny bit in a sandwich baggie at the bottom of my bag. I have done a ton of traveling, albeit without a dog, and I don't think they'd notice if I had just a bit in a baggie.
I just ordered two different bags: one
Sherpa Deluxe - Small and one http://www.westcoastpetsupply.com/2/Bergan-Comfort-Carrier/
I will probably only keep one and end up selling the other on YT or Ebay, but I'm not very good at online shopping since I like to have options, hold things in my hand, etc.