AA is a partner with TAM so there is a chance your flight may actually be a TAM plane... I've flown from Brasil to the US more times than I can remember on AA and TAM, sometimes I wasn't sure which plane it would actually be even though I always booked through AA. The only issue you'll have is that the food on AA planes is crap compared to what you have on TAM flights.
Not sure if this is your first international flight from Brasil or not, if it is then make sure you have the money to pay for the tax on your way out of Brasil you'll get hit with it when you check in at the ticket counter at the airport. If your flight enters the US at Miami you'll have an easier time communicating with the customs folks but the lines tend to be longer than if your flight goes directly to Orlando. Orlando lines are shorter but less likely to have agents that speak Portuguese.
The other thing you'll have to deal with that may be shocking if you get stuck on an AA flight is the stewardesses. On a TAM flight they are usually younger and still happy they have a job they love and it shows... On AA flights, especially international flights, they tend to be older and showing their disgust with their job... So don't expect nice service if its an AA plane it will likely be rude old women that hate their jobs and take it out on the customers.
