I would pack a ruck with rain wear, fire tools, a good pocket knife, a nalgene bottle or katydin filter bottle, a quality flashlight and extra batteries, compass, emergency blanket, modest firstaid kit. Enough to survive a night in the woods. If you make sure to leave a detailed itinerary at the trailhead or family member and stick to it one night should be the worst case scenario.
Make sure it all goes in checked luggage as the knife and likely some of the other things will get confiscated if not get you detained.