Traveling outside CONUS or even within the US via air is always a pain with a firearm, so I understand the question. If within the US, I don't have too many worries for checked-in luggage and many of my regular blades/tools accompany me; when traveling outside the US, I'll go with more "inexpensive" options.
A simple SAK (Outrider or Farmer are my top choices) and a Mora (prefer the 2K model) are pretty inexpensive and I wouldn't shed too many tears if they were lost or stolen. I have a few inexpensive "tactical" folders, such as the Benchmade Pika (I have a couple older models with ATS34 blades) or even a Buck 110, that would most likely come along as well. I just avoid anything custom or that has irreplaceable value.
Add a decent small FAK, small PSK, 550 cord, duct tape, compass, cravat/bandana, LED flashlight, fire-steel, matches (and/or Bic lighter) and a whistle...along with a couple inexpensive knives and you have a decent traveling package for day hikes that doesn't take up too much room.
ROCK6