NB UK car seats may not be suitable for US cars and vice versa.
newcomer link: http://talk.uk-yankee.com/index.php?topic=36523.0 [nonactive]
This is a valid point, perhaps I should clarify.
My two are now in booster-type car seats, for 18k+, allowable here and in the three states I was driving in, for children of their age. I checked it out on the state websites before travelling.
We flew with Virgin, and they weren't included in the limit, as of three weeks ago. If I were travelling on an airline that *did* charge and they were still in heavy babyseats, I wouldn't take my own. But the booster type things are so light I'd still pay the excess.
BTW, they were exactly the same brand - Graco- and model that we use in the UK. My point is that the rental agencies don't discriminate between an an expensive babyseat and a booster that costs under $20 in Walmart- they are all the same daily rate.
Hope this helps somebody.