A.F.
Did you try a graco ? I had two different ones and I liked them both. what you may want to do and remember is even though the baby is small, you don't have to carry baby around too much in the carry on. My son was forming a start of flat head in the back and it was because he was on his back too much. So we started to alternate his body position and he was fine. Remember it isn't healthy for baby to be in a baby car seat for too long . Don't ever let the baby sleep in there as in example a friend's house or supermarket shopping. Bring baby in a sling wrap around, it is more beneficial. I went to a training from my job once, and there was once a very tragic story of a baby that was brought to daycare in an infant car seat, carry on. The baby mustv'e been in there for too long I guess when they went to touch the baby, she was dead !
I will never forget that. We have to remember the child is in there strapped in and a little tighter than normal. As it is more comfortable for you as well not to carry baby around in a heavy object !
They are suppose to stay in the vehicle, only bring the carry on with baby in it, if you really have to. Take baby out of there as much as you can. I stress about this because I have seen too much of the " bucket baby "
It isn't fair for the innocent child. I don't think we would want to be carried in that form everywhere.
Hope I helped. Hope I did not sound harsh. I just care.