Which is better for (very small) 2 year old on a 4+ hour flight - a capsule carseat (installed RF) or a convertible carseat (I assume I'd need to install it FF)? I'm asking "better" in terms of practicality, not "which is the absolute very safest" I have both kinds of seats that are FFA approved, so do not need to make a purchase either way.

Last time I flew with her, she wasn't walking, so I didn't get her own seat - this is a longer flight, and she's mobile, so I feel like some kind of restraint will save my sanity.

We're flying economy, and have a full row of seats (me, my 4 or 6 year old, and the 2 year old will be together).