That's the rumor, anyway. For quite a while, AA has been enticing travelers to buy tickets only on its own site, aa.com, with its DealFinder widget, which offers 10 to 30% off on various routes with the use of promo codes.
According to this blog post, cash-crunched American no longer wants to pay double booking fees to both Kayak and Orbitz (fares found on American via Kayak are sent not to aa.com but to Orbitz.com for booking).
Southwest, of course, already does very nicely by not listing on Kayak or any other site. So perhaps American is thinking, hey, why can't we go it alone too?