A.F.
You can bring liquids through in the diaper bag greater than 4 oz. In Boston they just request that you put them in the bin sepeartely and declare that they are for the child. I typically bring two boxes of milk in addition to a few juice boxes. The only thing I was not allowed to bring through was water as I was told that was not something they considered specific to the child's needs. My daughter is 2 and we've flown more than a half dozen times in the past 2 years -usually from Boston to Nassau (about 3 hours direct) but we've also got to California. I've found that the portable DVD player was extremely helpful with a baby einstein video or two. I also bring books, puzzles, and finger puppets. It's not easy finding toys that a) interest a toddler and b) don't make noise! Lastly, snacks that take a long time to eat like Cherrios and raisins where you can give them one piece at a time worked well. Don't forget to throw in and extra change of clothes in the daiper bag. Murphy's Law- if you don't have it, your son will squirt his juice box all over himself!