1. Gate check a stroller. Most companies allow you to gate check a stroller, depending on their regulations. This was a must for me when I traveled by myself with toddlers. I used a Mountain Buggy (Urban Jungle) and I cannot tell you enough how much I love this stroller. It works wonders when getting to my destination as well. I often travel to Europe, and I need something sturdy that can handle anything from beach strolling to forest hiking. I also used a smaller stroller from Gracco, which was also great when the kids where smaller.
2. Even though I had gate checked a stroller, I brought a Baby Bjorn carrier on board. It helped me to put my son to sleep in no-time, and it saved my back during the flight.
3. A good diaper bag, with lots of smart solutions in it. I have a crush on Skip Hops bigger version and I have used them a lot during flights.
4. Anti-bacterial wipes. Do not think twice, just go get them.
5. Spill free cups. How I wish I had brought one of these that flight when my kid poured all the juice over me…