I noticed back in August that AAdvantage miles were posting to my account within a day or two of a flight. Apparently, American has upgraded their system so that AAdvantage miles earned by flying will post within 24 to 36 hours of travel. Nice improvement.
This is from the announcement on their site:
The next time you fly on American Airlines, American Eagle or an AmericanConnection carrier, you will notice that your AAdvantage miles post to your account faster. If you’ve flown with us recently, you may have already noticed this change.
We are always looking for ways to improve the AAdvantage program, from special promotional opportunities, to more ways to earn or redeem your miles. Because we know your AAdvantage miles are important to you, we have been working on improvements to our processes. As a result of these changes, your miles for travel on most flights on American Airlines, American Eagle or AmericanConnection will now be credited to your account by the next day.*
Need some ideas for using your AAdvantage miles?
Use your AAdvantage miles for your next trip. With One-Way Flex Awards, it’s easier than ever
Check out Hot Spots for destinations with available award seats in the coming months
Upgrade yourself to First or Business Class using a mileage award upgrade.
*In most cases, AAdvantage miles associated with your flight will post within 24 to 36 hours of your arrival day/time.