A.K.
i looked around on the internet. is your daughter in a booster seat? i found one site that had a car seat, high back booster on wheels so you wouldn't have to carry...
http://www.thecarseatlady.com/airplanes/airplanes_7.html
i'm sure there are alot of options. you do not have to put a carseat on the plane. that i know. you can use it as baggage and check it in. we took my daughter and her car seat in the plane on a family vacation and that was just crazy. the isles are just impossible and people are rude. it's not a legal thing. taxis' i'm unsure of. but i'd want one for safety reasons... look for a small booster that's light weight or one that you can roll per the link up top. good luck and i hope you have a great vacation!!