We're looking at flying to Japan this coming Fall. DD will be 3, probably will be 33-35ish lbs at that point (she's right around 30 now). She's currently about 3ft tall. We will not need a car seat while we are there at all. So I really don't want to bring a car seat and have to lug it around Japan for 3 weeks (along with my two other boys, who are both over 4/40). What I'm wondering is if the CARES will provide significant enough of a safety advantage over just the lap belt for DD? I don't like how it makes the lap belt ride up and wonder if in some way that makes it less safe (I'm thinking abdominal injuries). She's pretty good at sitting, so I'm not too worried about the wiggles and not wanting to buckle. Usually she'll do anything her big brothers do, so that helps. And also, I know that crashes are exceedingly rare and think that in case of turbulence the lap belt would probably keep her from flying around (I'd worry more about submarining in a rare crash, which the CARES won't help with anyways).