Law Lord,
My daughters have flown, both coach and first, since they were 4 months old. We always brought the car seat for use on the plane. This way they were in a familiar spot, and thus very happy. As others have mentioned, lots of NEW toys, crayons, and snacks hepled. Most airlines offer peanut butter and jelly sandwiches for the little ones, which are always a hit. Don't forget the pacifier, and a bottle for takeoff and landing.

Enjoy !

To quote Abraham Lincoln:
We never stand so tall as when we stoop to help a child