Via Reddit, some people are getting targeted offers for the Barclays Aviator Red offering 1000 AAdvantage miles for adding an authorized user by December 31, 2015. There seems to be no spending requirement attached to this offer.
I personally also received an email title Earn More Miles this holiday for my Barclays AAdvantage Aviator Silver with the following:
There doesn’t seem to be any date restriction on my offer, but there’s no reason not to take advantage right away. So check your email! It’s an easy 1000 miles.