Re: Help picking a convertible seat - Air travel
The Radian fits many kids from birth-- but doesn't fit RF on planes well unless you're able to get the bulkhead seats (and sometimes not even then-- depends on the plane), which is not always possible.
The Diplomat is outgrown well before other seats, I just don't consider it worth the money.
The Signo is heavy and doesn't give much leg room to older rear-facers, and is often awkward to load a rear-facing child in because of extremely high profile.
The Complete Air is a great seat and JUST barely fit on the Southwest 737s we flew on last month, with only slight difficulty. However it has such high slots that when installed more upright (and it will install upright) it may not even fit a child that young properly, depending on torso height. (It fits at about a 30 degree airline on the planes we flew on.)
For convenience on a plane and lugging through the airport-- I'd be looking at the Cosco Scenera and the Safety 1st Avenue, and learn to use a locking clip if you're going to a foreign country with non-locking shoulder belts, OR the Combi Coccoro, which will not last as long but is VERY convenient for travel with littler ones, and has a lockoff.
I also would consider taking the infant bucket. It doesn't sound like she will have outgrown it. (You have until her head is even with the top of the seat, as illustrated in your manual, or until she reaches the weight limit, which she is nowhere near.) That way you won't have a fight (on an American airline, anyway) about which way to install it (yes, I would recommend rear-facing for children under 2, even on an airplane-- while mostly you're holding them down during turbulence, there is the very occasional incident on the ground and you want your child properly restrained if that is to happen. Plus, they sleep better.) Again, practice without the base and with a locking clip before going. What airline are you flying? What country are you going to?
CPST and Mom to Emma, 12, Bridget, 10, Maggie, 8, Katie Sue, 4
and Becky, waiting for us as part of our eternal family.
Our '02 Odyssey, car seats, and seatbelts saved our lives.
Now riding in a '13 Odyssey!