I have always been told they need to be in the bottle with proper labeling. I checked into this before were planning a trip a few years ago (didn't end up going..we would have been flying so I was more concerned). I take 4 different meds (3 prescription, one OTC sinus) each night for migraine control, plus have 4 others I can take as options for migraine aborting should I get one (different levels of pain relief). But I get all of my meds from a mail order deal required thru our insurance, and get them in 90 day supplys. SO the bottles are huge!
If we were to fly and I needed to bring all of those bottles..OMgoodness..I would certainly look like a druggie! LOL. I always wondered about getting smaller bottles and what the hassles involved would be to get the smaller bottles from the mail order pharmacy for such a purpose (like for a 10 day supply).
I never needed to. But when we travel over the road (we go to the mountains most years, or other trips where we cross state lines, etc). I DO bring all of those gigantic bottles..along with any other medicine cabinet type thing you can think of. We go to some remote places in the mountains to snowmobile...and in the "town" your only options to get something as basic as Advil will likely be the local gas station/sled shop/diner/everything else! So that 10 pk of Advil might cost $8 or more. So I bring it ALL! And its often been used too (we travel with a crew of almost all men..usually there are 1-3 women with up to a dozen men..the men have a tiny duffle bag and then tools and sled gear. They come to me when they need Rolaids or Pepto..Advil or a sinus med. Just the way it is. Dumb boys! LOL)
Definately check the TSA and airline policys....know before you go! It could be a HUGE deal!