How can I get from Miami airport to the hotel if I don't have a car seat for my baby?

Since you have two adults, one of you could drive the rental car from the airport to the hotel, and the other could go with your baby in a taxi or shuttle (or some service that provides a child seat).

Perhaps a solution would be to have you (or your husband) rent the car, drive to the Mall of the Americas, as there are stores there that sell baby related products such as a car seat, then come back to the airport and pick you guys up.

The Mall is across the highway from Miami International Airport.

Or why not buy the car seat while you are in South America, then bring it to the US to use? Generally international flights include checked luggage, and since you are already planning on bringing it from the US back to South America, I don't see why it's a bad idea to bring it round-trip. If you purchase one that is can be used on the plane as well as a car, that might be even better.

(fine, this particular trip is long finished.....)

Lets review the key points:

• You are renting the car for 10 days, but only want a child seat for one day. Hertz doesn't do that.
• You are renting the car at an airport.

Make two reservations:

1. At the airport for one day, with child seat, returning to a non-airport location.
2. At the same non-airport location, without child seat, for the rest of your trip, returning to the airport.

You get two benefits here:

• The car seat is only for the time you want, not the whole rental
• The airport location charge only applies to the one day, not the entire rental. At $110 a day for a minivan and 15% for the airport, this fully pays for the car seat.