Besides the obvious necessities, such as luggage and money, here is a list I compiled of 6 traveling articles that I have found to be immensely helpful in my many travels.
Cuz you never know when you'll wake up from a nap and have horridly smelling breath...
Earbuds are easier to pack and you can have a neck pillow on at the same time, whereas headphones make it a little more awkward. But headphones block out more sound. So just decide which you want more - a comfortable neck, or absolutely no noise.
I promise you won't regret this. Either one for your neck or an actual full size bed pillow.
4. Hand sanitizer
Because when you really think about everyone else who has sat in the seat you're in, touched the armrests, maybe coughed or sneezed...yeah...
Depending on the kind of traveling you're doing, this may not be extremely necessary. But for me, long flights or windy drives call for one of these life-saving pills.
6. Ponytail holders (if you're a girl. OR a guy with a man bun)
These things always seem to disappear. But even more so when traveling. So be sure to have some extra ones handy. I like keeping them on a key chain attached to my backpack so you know where at least a few of them will be.
You never know when you'll get hungry, if you can stop for food, when the airline will serve refreshments...
8. Cozy socks
Sometimes the temperature drops, or you just want to be snuggled in warm clothes for a travel nap. Socks definitely help with this.