I am 100% in agreement with this. I think trained dogs or a dog school would be great. Maybe trained, docile cats for those that don't like dogs, but that would be more difficult. But something more than a piece of paper, and it needs to be restricted to certain animals.Maybe they should train a line of service dogs to be docile and caring to be actual certified support animals. I would absolutely be fine with that! Not to say you can't own other dogs, but THIS is the trained dog you can bring with you in places like planes. OR take your own animal to get trained, like a doggie school.
When it comes to other non-dog animals to bring into public... it gets tough. That story of the turkey being brought on a plane... yeah I wouldn't trust a turkey I don't know to play nice with people. (At least that story turned out fine).