Hello. My 4yo son is 39 pounds and 41 inches tall. My uncle has offered to give him a ride in his SR 22TN G-3, but he is concerned that his cirrus has a shoulder harness and would not fit a normal child seat.
I have a booster seat, but i’m not sure if this would fit the scenario.
I’ve used the regular bottom only style booster seat. All depends on how big the child is. The good news is that the four point seatbelts are fairly adjustable to be able to pull low across the hips. But you would need to see how it fits your child in the plane first.
My daughter in this photo is 6 yo and about the size of your child. I use a bottom-only booster to make sure that the belts fit her correctly. I don’t want the larger and heavier bottom-and-back boosters in the cockpit. She’s quite comfortable in this setup.
Here’s a 5yo in a Graco booster with back (complete with secured and hearing protected companions). In the rear seat, the seat belt did sometimes ride up and had to be checked periodically. In the front seat, the seat belt was easier to keep “low and tight.”
LATCH makes an appearance in the G5 generation, so if the 4yo still fits in a convertible car seat, then that could be an option too (no personal experience).
I like Max’s setup too. I think it ends up depending on the size of the child. In terms of convenience and ease of setup, it seems there’s a rule of thumb that the kids move up a level of car seat compared to what they would be in a car.