Replaceability is definitely a good thing to consider (especially when traveling by plane), but to be honest, I don't always follow that rule when choosing knives to take on a trip. It's just a risk that you can decide to take (or not), I guess. If replaceability is a factor that's important to you, then I'd second the suggestions of either an SAK or Opinel.
@Modoc ED's suggestion of stuffing your packed knives in a pair of socks is a great suggestion.
Here are some photos I've taken on recent vacations that show the knives I chose to bring with me.
This past weekend we drove to Arkansas to visit family. I brought my 2016 Forum Knife, as well as a #25 Barlow that I carried one day but never took a picture of, and my Ebony Lambsfoot.
Last summer we visited my brother and his family in England. Legality had to be kept in mind for this trip, as UK laws require blades to be under 3" and non-locking, but for traditional knives, I didn't find that too difficult to manage. I decided on just one knife for the trip, and went with this spearpoint Tidioute #25 in Ebony. Easily fit the size requirements, while still providing a stout enough blade (that's one of my favorite things about the #25 in general). Since it was the only knife I had with me (and my first trip to England), I took quite a few pictures.
A month of so before that, we flew to Texas for my cousin's wedding. For that trip, I brought along a #13 Whittler and a #71 Bull Nose.
I thought that made a pretty good traveling combo, providing a nice variety of blade shapes and sizes. The Bull Nose came in handy when it came time to eat at the wedding reception, as by the time we got food they had run out of silverware (except spoons)! The Bull Nose worked great as a knife (obviously), and pretty well as fork, too.