American has sub-fleets of both ETOPS and non-ETOPS A321s. In other words, some are certified to fly under ETOPS conditions (ie, over oceans), while others aren’t. And it’s important for airlines to get that right. Well, it seems like on August 31, 2015, American didn’t get that right. On that day, American flew a non-ETOPS A321 — with tail number N137AA — from Los Angeles to Honolulu.