When you have kids traveling with you, it is always best to bring stuff that would occupy their mind during the flight or when on the road. I always prepare and bring my kids things like Lego pieces , books, notebooks, pens and pencil, and snacks. My daughter love to draw or write when we travel so I always keep that in mind.
My son on the other hand love to build things so lego pieces are perfect to bring for him. I just make sure that they are in a ziploc bag so he won't lose any.
Snack and drinks are very important as well. When you have snack in the car during a road trip, it eliminates the stop on food chain unless of course for rest stops which is necessary.
We are going on a road trip next week so it would be something that we are looking forward to.