Maybe I'm missing something, but it seems that they won't give you a charity receipt for the full amount you donate. Instead, they deduct the "fair market value" of the miles at a dreadfully high rate.

Meanwhile, AA gets to claim a "donation-in-kind" to the foundation at that same inflated value, far above the actual value of the miles.

For example, if you donate $1000, the miles will be valued at $137.50. So you only get a deduction for $862.50, while AA has just hijAAcked $137.50 of the deduction.

Seems to me you'd be better off just donating to them directly and getting the full deduction you're entitled to, rather than letting AA get a $100+ writeoff for something with a value closer to $50, and a cost to them of less than that, on average.