I've gone back and fourth from the US to EU quiet a few times now, my DS is 7 months and I think he has more passport stamps then my parents do
I found its good idea to bring a change of clothes for him and I. Snacks/pacifier. A few small toys and a few magazines (he digs the faces). I am lucky in that my DS almost always sleeps the whole flight so I rarely need extras.
Generally international airlines/airports are surprisingly kid friendly and even more true with babies.