+1 for Cosco Scenera. Most lightweight seat you can buy. It’s a little tough to get the straps adjusted in the car, but definitely my go to. We use it with the Chicco travel case.

At 8 months, we usually did lap child. An alternative to getting a whole row if you’re going to spend the money is to upgrade to First. The larger seats and pitch make it more comfortable to have a lap child and the large armrest is good for placing extra toys, bottles, etc.

IMO, 8 months is a bit young for a CARES harness, but consider one of these as the baby gets older—much easier to carry and install on the plane.