He sat still. Lap time is great for story telling, reading and activities. Sometimes children have to learn to sit still. It's never easier. Each age has its own special issues to deal with.
Babies sleep but their ears are more sensitive.
Toddlers want to move and be active and older children get bored. So for each age, your child needs the right stuff to make the journey. However, we are planning an auto trip this summer when she will be 7 months. When we are prepared, our child enjoys the trip even more. This includes snack, changes of clothes, a travel play bag filled with favorite things, emergency supplies, snacks, juice and water.