I understand that there are people who really do benefit from an emotional support animal - veterans with PTSD come to mind first, but...a peacock? They are gorgeous, but don't they have a well-deserved reputation for being loud and MEAN? Not to mention, I cannot imagine that a trip like this would be good for the bird.
From my POV, these people with the 'wacky' support animals are just wanting attention. That might sound mean, but it's my belief, and people aren't going to change my mind. There was a news story a couple of years ago about some woman bringing a Turkey on board a plane. I'm sorry, but it's just not okay with me. Birds and reptiles are a couple of the most salmonella-ridden animals around. I don't want them around me.