Each airline will treat you about the same unless you are springing the extra money for first class, but I can give you some tips for flying with kids in general. The kind of service you get will depend less on the airline you select and more on the particular flight crew working your flight. I have seen FA's who have been very acommodating to folks with kids on USAir, Delta, NW and Jetblue--- the only airlines I fly--- and I've seen FA's on the same airlines who couldn't be bothered with helping one bit. It's really the luck of the draw!
-Request a bulkhead seat assignment. Kids love to kick the seats in front of them which is annoying to other passengers and puts parents in an uncomfortable position. When you sit in the bulkhead, you don't have a seat in front of you, so there's no temptation to kick and you might have an easier time keeping the kids settled down.
-Request an infant's fare for the 1-year old instead of carrying the baby in your lap. That lets you bring the child's car-seat into the plane itself and secure it to the seat. This is definitely the safest way to fly with a baby (if you have an emergency landing or worse, the risk of injury to an unrestrained baby is extremely high even when parents are not hurt). Plus it lets you have your hands free to care for and entertain the baby.
-If you can get a direct flight, do it. Connecting flights are stressful for all travellers and even more difficult when trying to navigate through crowded terminals with little ones in tow!
-Your 4-year-old will probably want to carry one of his/her own bags just like a grownup. Pack this carefully as he/she will get tired of carrying it pretty quickly; just a few light items that you will need inflight.
Jetblue because of the games and tv's they can play [[individual]] =). Iwould say Delta Song but I think they went out of buisness..
Jet Blue or Song the satellite TV's will keep them occupied.
Continental Airlines. They Are Most reliable and wont bother you about kids. Their flight is very comfy too.
british airways, american or delta
See if there are any Southwest airlines flying that route. They are the best, with amazing service and always a smile on their face. Plus, it isn't set seating, so you just get on the plane wherever you want.... try to get in the front!
Hope I helped!