I got a car rental receipt. How do I do this? I call Dollar, identify the rental by rental agreement number, and ask for it to be credited to the AA account?
I finally found the answer.
I called Hertz (got a rental from them) and the rep had no clue and told me I need to contact the airline.
Didn't seem right, so I poured over all of Dan's material and this thread and found tucked in somewhere that indeed, you contact the car rental to ask to claim your earned frequent traveler credit.
On Hertz site, I found a form to fill out to get the credit, and it gave all its partner airlines as a choice.
They asked for name and address, that I hope was meant to be connected to the airline account.
They'll let me know within 24 hours if there's a problem.