N.V.
Everyone seems to have given you very good advice. The only thing I have to add is regarding the formula. You can bring the powder but not the water. I found it easier to spend a little extra and buy the pre-mixed formula. As long as it is unopened and clearly labeled as baby formula they will allow it through. It saves you from trying to mix a bottle on the plane as well - it can get bumpy and messy. And if you can afford it, absolutely buy the extra seat. It makes a world of difference.