I don't really understand why there is any concern for that layover even with kids in tow. Atlanta is very easy to navigate and Delta tends to pad their schedule so your layover will be longer. It's not like your going to be let on early to put the car seat in and I honestly don't think it'll take that long to do. It is slightly irritating to me that they would put you on a nonstop flight when you could have purchased that from the beginning.