Thinking back to my last flight
....
baby wipes, nutrical, blanket, pee pads, poop bags, water bowl, buy bottled water at airport, and chew toy.
Depending on the flight crew and those around you, you may be able to keep your baby on your lap. I had a very long trip back home with one of my pups (3 flights - 12 hour total travel time) and on all three flight the stewardess overlooked the fact that my little boy was on my lap.
Luckily, he was quiet too. Everyone around me was also very pet friendly too.