Tranzitions 3-in-1 Harness Booster

What seat is she in normally? I just flew with the Graco Tranzitions, which is FAA approved in harness mode. The WayB pico might be an option. I think it has quirks based on your child’s size though

Maybe something like the graco transition would be good. It’s shaped like a booster but has a 5 point harness. Then can grow with them into a booster seat when they get bigger. The ride safer vest could also be a good option travel and portability wise.

4 year old can possibly use a cares harness on the plane so you can check that car seat. Cosco scenera is a really lightweight car seat. We bought a cheaper Graco tranzitions harnessed booster for our 3.5 year old for our last trip. It was super light so we put it in a backpack case and gate checked it, he used cares on the plane. Our 1 year old had a Graco slimfit3 and we put it on a folding cart and used it as a stroller in the airport then installed it on the plane. We just happened to already have that car seat so it was convenient for us.

If it was me, I would rent for the 4 year old and bring for the 1.5 year old. The 4 year old is big enough to use a CARES harness and a cushion thing and will still be comfortable, AND I feel comfortable getting a four year old tight in a rental car seat. We use a Travel Snug brand for our kids, but there is also Seat to Sleep brand. As for car seats, people rave by the lightness of the Cosco brand and the Pico Wayb. I instead upgraded one of ours to an all in one (car seat to high-back booster) and literally chose the lightest one. It is half the weight of the one it replaced, so there is a ton of difference in weight out there! That then goes in a backpack style bag, which is my husbands preference over another cart to push.

These are the three things I have for travel (note we take two 12-18 hour flight trips/ year, including a redeye, so this may not be the right routine for everyone): An older version this this car seat: [https://www.target.com/p/graco-tranzitions-3-in-1-harness-booster-car-seat/-/A-53567836?preselect=75557343#lnk=sametab](https://www.target.com/p/graco-tranzitions-3-in-1-harness-booster-car-seat/-/A-53567836?preselect=75557343#lnk=sametab) A Travel Snug with harness slots): [https://www.travelsnug.co.uk/](https://www.travelsnug.co.uk/) A CARES harness: [https://www.amazon.com/Child-Airplane-Travel-Harness-Restraint/dp/B0012E4FV8](https://www.amazon.com/Child-Airplane-Travel-Harness-Restraint/dp/B0012E4FV8)

We went from infant seat to extend to fit to Graco transitions to a cheap booster. But that's mostly because there was a sibling to use the next seat. Transitions can also be a backless booster. They didn't make rotating seats when my oldest was little so I never tried one.

The Graco Tranzitions is pretty lightweight, and it’s a 3-in-1 FF 5pt/HBB/no-back booster, so after the trip you could save it for later when he moves to a booster seat. Since it transitions to a no-back booster, you can take the back off to make it much shorter — so if you end up not having him sit on it on the flight, you could probably fit it into a carry-on bag for the plane, then put it back together at your destination. 

Pretty easy. I’d say <2 min each to take it apart and put back together. The manual has you take the harness straps all the way out when taking it apart since they’re assuming you’re about to use it in booster mode, but I don’t think you’d have to 100% uninstall them just to take the pieces apart. I can take a look at it tomorrow and measure how compact it can get when apart.

Agree nuna rava is super easy BUT It’s $$$ and def not a grandma spare type car seat. Diono radian is front facing 5pt harness and I find it easy to install, have it in my husbands car and often have to take it out when we are driving other adults. Chico kid fit high back booster very easy to install. Just attach to latches and pull tight at the front. FWIW I bought a Graco transitions as an extra for grandparents and anytime they take it out and reinstall themselves it’s insanely loose and not right at all. It takes a lot of effort on my part to get it tight enough.