I have autism and I am almost 35 years old. I have had melt downs at WDW also. I am mentioning this because I am proof that adults have meltdowns also. The worst one recently was in January when our Southwest flights early bird check in did not work properly and we wound up in the C group. I have serious issues being close to strangers and being in C group on SWA usually means not being certain of sitting with who you are traveling with. The idea of not sitting on the plane next to my fiance was very, very scary (I mean terrifying) to me and I just lost it. On the bus from CBR to Epcot, I just started wailing crying about it and my poor fiance just kept trying to calm me down. I'm sure there were some rolled eyes but normal people really don't understand the sensory issues and some of the seemingly odd fears that some people have. When we got to Epcot, we went over by the lockers and my fiance called SWA to try and upgrade our seats to business class so we could be guaranteed early boarding (I don't ask for early boarding for medical reasons because I hate the stares ). While he was doing that, I just sat on the ground crying. It was awful but so was the terror I felt at the idea of having to sit next to a stranger for 4 hours on a plane. I'm sure some people made some remarks but I didn't hear it. I've seen other adults have meltdowns as well, probably for other reasons but you never really know.