From the Washington County (Oregon) Law Librarian:
A couple of years ago, in response to a patron’s request, I sent out an email message to colleagues on a law librarian listserve asking if anyone had found an online source for AARP bylaws. No one had, but since then, I receive emails every couple of months from someone asking me to “please send me a copy of the AARP bylaws.”
I did find the bylaws back then. I phoned AARP directly and was sent a copy. (Sometimes the telephone still works better than any other communication device (though, it probably doesn’t beat out love, affection, truth, justice, pizza, or key lime pie).)
If you need the bylaws, please call AARP. Their public relations (aka press center, media relations) staff members were very helpful.