
Cosco Kids
Scenera Next DLX Convertible Car Seat
Super light, cheap, great for air travel, but outgrown fast.

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Get Cosco Sceneras! If you can find a retailer that still has some of the previous generation (Scenera Next) it will run you under $40 apiece. The new generation (Scenera Extend) will be more like $60 apiece.
We have it. It's bigger than the old version, but it's still functional and way easier than our normal convertible seats. Be aware that you cannot use it on some planes if the armrest won't go up. We had that issue and had to move seats -- luckily it was seamless but it could have caused problems if the circumstances had been different. Also be aware that the way it buckles into planes means the seatbelt buckle is right in the kid's back. Our daughter didn't seem to mind for the most part but we had to unbuckle it on a longer flight because she started to complain. Not as safe, but I think still better than not using a carseat. The strap does irritate my son's neck; he's 15 months and 30th percentile height and weight. I have to pull up his collar so the strap doesn't touch it.
Yes. It was even a permanent seat in one of our cars.
We bought a cheap seat that is light and a single molded piece of plastic. It wasn't ideal but it worked. Lots of places like the zoo have a coat check type of place that will let you leave it there while you are inside. Example https://fromrebel.com/products/scenera-extend-convertible-car-seat-moonlit-night-005a15
It’s definitely no-frills but my kids never complained about it, and it’s super light and easy to carry around an airport.
Definitely yes. We’ve used this for more than 20 flights (on United) for our daughter until she was 2, and have never had an issue. She slept it in seamlessly as well. Eventually around 26 months she just wanted to sit in the actual plane set, so at that point we just gate checked the car seat when we traveled, and used it in cars at the final destination.

Cosco Kids
Scenera Next DLX Convertible Car Seat
Super light, cheap, great for air travel, but outgrown fast.

Cosco Kids
Scenera Next Convertible Car Seat
Portable, affordable, quickly outgrown, airplane buckle discomfort.

Joie
Mint Latch
Easy baseless LATCH install, lightweight, but quickly outgrown.

Nuna
PIPA Series
High-end travel, easy baseless install, but very pricey.

WAYB
Pico™ Portable Car Seat
Ultra-light, compact travel, quick install, but expensive and outgrown fast.

Ranked #1
Cosco Kids - Scenera Next DLX Convertible Car Seat

Ranked #1
Cosco Kids - Scenera Next Convertible Car Seat

Ranked #1
Cosco Kids - Scenera Next DLX Convertible Car Seat

Ranked #1
Doona - Doona Series

Ranked #1
Cosco Kids - Scenera Next Convertible Car Seat

Ranked #1
Nuna - PIPA Series