Marriott Rewards and American Airlines announced reintroduction of their partnership, which ended abruptly few years ago, earlier this month. You can read my piece about it here.
Marriott is now offering 500 bonus airline miles for stays that are credited to American Airlines for stays between July 15 and August 15, 2013. You can earn this bonus unlimited times and there doesn’t seem to be a requirement to register for it.
I have not found this promotion on Marriott’s website, but you can access it on American’s website here.
Note that you need to switch your earning preference from Marriott Rewards points to airline miles and I would not do this. It is better to earn points and free night certificates and then later convert the points to miles via travel package option. You can read more about Marriott Travel packages here.
It was not unexpected that there would be a promo for bonus American Airlines miles for Marriott stays after the partnership returned. This is not lucrative enough, however, to switch myself earning Marriott Rewards points and free night certificates.