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

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All car seats in the country pass the same safety tests. If you got it new from a store, it's good. That particular one just has no extra convenience features, it's very basic. It's one of the most recommended travel car seats as a result, because it's cheap and lightweight.
I've heard of people attaching the Cosco Scenera NXT to a Mountain Buggy Nano, which uses a universal strap for the car seat attachment. I can personally recommend the Cosco Scenera NXT as a travel toddler car seat, it's very light.
We don’t have a car. For our first we borrowed a peg Perego seat and bought an uppababy adapter from marketplace for $10. We didn’t use it much so this time around we didn’t bother with the baby bucket seat and just got a convertible one instead. The Cosco Scenera Next is the smallest, lightest convertible. It was great but our first out grew it before age 3 (and she’s petite). For our second seat we got a evenflo titan. It’s bigger and heavier (11lbs vs 7lbs, I think) but it should fit until it’s time for a booster. Depending on your needs (lightest vs light and longest fitting) you might want to look into one of those seats
We also don’t have a car. We mostly use public transit because car seats are a pain in the butt. A couple tips: 1. We had the Cosco Scenera next. It is very lightweight and easy to install. Be aware though that it is outgrown fairly early and can basically only be used rear facing. The reason front facing is outgrown first is that the straps must be at or above the shoulders for front facing, whereas they must be at or below the shoulders for rear facing. Our petite child is freshly 3 and is too big for it. We upgraded to an evenflo titan 65. Despite the name, it’s the lightest weight seat we could find for a bigger kid. It should fit until the child is big enough for a booster seat. The smaller, lighter size of the Cosco seat was worth it for us and we’re now using it for our second child, but if money is tight you might consider getting the titan 65 right away even though it’s a few pounds heavier. 2. Not sure what uber is like in NYC, but in my city I prefer to use taxis for a couple of reasons. One is that they won’t turn you away with a car seats because they’re worried it’ll take a long time to install because they can just run the meter while you get everything set up. The other is because most taxi drivers are older and have kids of their own, so they’re much more tolerant of parents and kids.
FYI the Scenera is outgrown at a fairly young age (around age 3 for our petite child and likely younger for bigger and especially taller kids). We switched to an evenflo titan, which is heavier and bigger but will fit for a long time and is still decently portable.
My everyday carseat isn't rated for use on an airplane. I did end up having to buy a second one, which was a bummer, until I realized it meant I never had to move a carseat to hubby's car ever again. [this one](https://a.co/d/0hjkvLyg) is inexpensive, and did the job well enough! Edit: just saw another poster mention the buckle being uncomfortable if your child is front facing in the carseat! So if your kiddo is front facing, ignore my recommendation. (except about having 2 carseat being great... I will die on that hill. 2 car seats for 2 cars in our household!)
That is a great note, I only ever uses it rear facing!
I've used both (on various airlines). Serena next is great seat. Very light and safest option. My child slept really well in it when older brother (and therefore me) didn't get any sleep. Cares harness is obviously more compact. Kids need to be able to sit upright but you should be OK at 20 months. I've heard it good to used grip mat underneath as kids can slip down but while I had one packed when we used it I didn't pull it out. Its probably easier for them to wiggle out of and I suspect its not quite as good as car seat in turbulence but much much better than nothing. While cares harnesses are airline approved many flight attendants aren't familiar and some will worry about it obstructing table on seat behind. It doesn't do this on most planes and safety trumps tray table use but I would print or screen shot the part of the WJ page that says its allowed. Make sure it is a legit version. In saying that I've not traveled with young kids on westjet yet (have some flights coming up) but Air Canada staff were also confused by car seat (screna next) with my 21 month old son (paid seat) even though it was totally required.
Not sure its "required", but we have used this model car seat multiple times for our 2 - 3 year old. Honestly, it is great! Shorter flights, but he stayed in the seat other than washroom breaks. Did not need to be fastened other than takeoff landing. Also recommend a car seat carry bag, allows you to wear it like a backpack through the airport

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