Nothing beats a Leatherman (sorry Victorinox). With locking super sharp blades and heavy duty construction, Leathermans are serious tools.
I personally prefer the Leatherman Wave, which has a nice combo of tools and yet still fits in a pocket. If you need a hammer, you even can bang things with it folded up.
You never want to have to borrow a knife when traveling – always have your own. Who knows where another knife has been? A Leatherman is essential for travel independence.
Needless to say, don’t take one of these in your carry-on.