I use my daughter's Recaro Pro Ride carseat in the airplane. She is currently 3. The only downside is that the seat is heavy. I remove the seat back cushion and stick. To buckle it in, I run the lap belt through the carseat and then connect the top anchor to the should harness. It gets her up several inches which allows her to see out of the cockpit, which she really likes. The carseat is high enough it leaves me plenty of shoulder space as well. Here is a recent pic.