Especially with small ones, making a packing list with categories is an absolute must! Make a list for each kid before hand and keep it on the kitchen counter, so you can easily add to it whenever you remember something. You may group your items into different categories.

According to your destination, travel length, and way of transport, you may need some of these things:

Eat

Cutlery, plastic bowls, bibs, snacks for the trip and for the destination, baby jar foods, travel high chair, sippy cups, milk bottles etc.

Sleep

Pajamas, bed sheets, travel cot, favorite comforter or soft toy, music box, dummy etc.

Play

Inside toys - brain teaser games, puzzle books, travel board games

Outside toys - fold up Frisbees, soft balls, buckets, etc.

Clothes

Limit clothes for the kids to use up more space. Rolling them up and putting little toys, socks or undies inside shoes in bags also save on room.

Mini Medicine Chest

Car/Plane Stuff

Planning in advance with a categorised list will help you remember pretty much everything you need and if you have forgotten anything, do not worry... you can always buy it (unless you are stuck in the middle of nowhere!).