How to keep entertained on a plane with a lap baby?

My son will be 8 months old on the 11th. This will be our 3rd 6 hour flight with him in my lap since April (Along with a small connecting flight which doesnt bother me).We will be leaving Hawaii to move back to the mainland (Funner place to visit then to live). He travels on my lap with me, and he is pretty good, but I can't keep myself entertained and these 6 hour plane rides are making me go crazy because I have trouble bringing anything out of our carey on and its just very crowded with a baby on your lap, I really need to not go insane please give me good ideas.