To use that facility, you need to be flying in first or business class or have AAdvantage Executive Platinum, Platinum Pro or ConciergeKey status. Oneworld Emerald status and British Airways Premier status will also get you access.

Holding AAdvantage Platinum status does not provide complimentary access to American Airlines Admirals Club lounges for standard domestic travel. However, as a Platinum member, you are also a oneworld Sapphire member, which grants you access to Admirals Clubs (and other oneworld business class lounges) when you are traveling on a qualifying international flight marketed and operated by American or a oneworld partner. This includes long-haul flights to Europe, Asia, and deep South America, as well as some shorter international routes. If your travel is strictly within the United States, you would only have access if you have a separate Admirals Club membership, are flying in a qualifying transcontinental First or Business class seat, or purchase a one-day pass for $79 (subject to capacity). Platinum members also receive access to American's more exclusive Flagship Lounges when ticketed on qualifying long-haul international flights in any cabin, providing a significant upgrade over the standard Admirals Club experience.