I cannot comment on bulldogs or emotional support dogs, but we travel a few times a year with our 2 little Poms. They always have to be in a carrier under the seat. They are $150 per leg per dog on AA. If we have a layover or even once we get to our destination the "boys" go on a leash to stretch their legs & a quick run outside to pee. Me & hubby take turns where one of us sits with the luggage & one walks the boys (which is probably what the celebs without carriers in the pics are doing). Never had any issues with them being walked around an airport on a leash. People go gaga over them. Makes me feel like a celebrity!