In 2026, you generally cannot enter an Admirals Club unless you have a same-day boarding pass for an "eligible flight." An eligible flight is defined as any flight marketed or operated by American Airlines, any oneworld® alliance partner (like British Airways or Qatar Airways), or Aer Lingus. Even if you are an annual Admirals Club member or hold the Citi® / AAdvantage® Executive card, you must be flying with one of these specific partners to clear security and access the lounge. This is a strict change from previous years when members could visit regardless of the airline they were flying. If you are flying a non-partner like Delta or United, your Admirals Club membership will not grant you access, making it vital to check your airline's alliance before counting on lounge time for your layover.