AA is the only US airline to use Aviation (UA/DL have Bombay Sapphire, AS has Tanqueray). Could be a supply chain issue that some stations aren't able to source it, or it could be that AA is switching and some stations are depleting their stock.

From an airline Food & Beverage perspective, one of my happiest moments was when Beefeater got out of the US mini market, forcing AA/UA to switch.