One thing that doesn't noticeably change w/Platinum over Gold is the way you're treated at the airport and on board. I find that I get all kinds of treatments, from rude to wonderfully attentive, in a very random fashion. It basically depends on the agent's or FA mood and seems to occur regardless of elite level. In this respect, AA differs greatly from UA. My husband, who is both AA Plat and UA PremEx, found a huge difference in the way he was treated after he reached the second elite tier at UA, but hardly any at all when he got Plat. on AA.