We really like our First Years True Fit Convertible car seat. Our daughter is now 2.5 and is still rear facing in it. You can stay rear facing up until 35 lbs in the seat and forward facing for quite a long time as well. It comes with pads so smaller children can easily be made safe as well.
http://www.learningcurve.com/wps/portal/truefit
It is cushy, comfy, fairly easy to use, easy to adjust, and the cover is machine wash/air dry.
Our plan is to keep our daugther rear facing as long as possible. It is proven to be the safest position.
Find info on that here-- http://www.car-safety.org/
And yes, it does fit on an airplane, although I'm not sure it would fit rear facing. It might be too long. We got it after she was about 16 months old... we could still use her Graco Safeseat until then since it goes to 30 lbs and 32" tall. (My goal is always to get my moneys worth so I choose seats that I can use easily but will also last as long as possible)
Please let me know if you have any questions. I'm happy to give feedback. Our current seats are in a Honda CR-V and a Nissan Xterra. We also use them in the middle seat always since that, too, is the safest spot.
Take care and good luck!
PS-- Did I mention I'm an unbelievable researcher? The First Years used to be a Compass but the company was sold to First Years. I looked into Britax and everything-- in the end, the pluses of this seat sold it for me, especially since we needed two.