I tried to find a post I made after our trip this past Feb, but for some reason can't find it.

Anyway, my husband and I took our then 3 y/o grandson to WDW. We booked our flights about four months in advance on American and chose seats together. (When booking, I did check the box that my grandson was a child.) I checked them periodically to make sure they didn't change. One day I got an email, that my husband's flight itinerary had changed. They did not even mention mine or my grandson's, but when I went online I found they had moved me and my husband to a flight that left Orlando about an hour before our original flight. When I called to check about my grandson, at first the CR had a hard time understanding why I was upset. She said the flights were oversold and they had to move me and my husband and the third member of our party could just meet us in Dallas an hour or so later. When I said, "yeah, like I'm going to leave a 3 y/o alone in the airport in Orlando while I board a plane". At that point it was like a light went off in the CR head and we both laughed. She finally said, yes, she now saw where he was a child. For some reason the computer did not pick that up when they moved us. She put me on hold, then came back to tell me she had moved someone from our new flight to our original flight and then moved my GS to our flight. I had asked her to move me and my husband back to our original flight, but she said it was easier to move just one person, so that's what she did. I then asked her about our seats that I had originally picked together. She told me that since it was the airline's fault that we had been switched to another plane that she would see what she could do. She came back and told me she had moved a couple and a solo flyer around and was able to get us three seats together, but they were in the back of the plane, instead of up closer to the front where we had originally chosen. Fine, at least one of us was sitting with our 3 y/o GS, which is all I really wanted. I continued to check our flights all the way up until the morning we flew down to Orlando and they were fine. However, the day we left Orlando to come back home, I got our boarding passes from the resort airline check in desk at POFQ and did not bother to look at them until we were on the DME bus on the way to the airport, at which time I saw we had been assigned seats all over the plane and were sitting no where near each other. As soon as we got to the airport, we ran to the AA desk where we were told to talk to the gate agent and they would try to get at least one of us seated next to our 3 y/o GS. Once we got to the GA, she said for us to tell the FA once we were on the plane and either they or we could ask someone to switch with one of us and it shouldn't be a problem, since my husband had been assigned an aisle seat and most people would not mind switching with him. However, it did not come to that. We were called back to the desk a little while later and were given the first row of seats on the left, after first class. They had apparently been holding those seats open for some reason. We were very relieved, but did not appreciate the stress, when we had picked out seats at the time of purchase. AA is the one who had switched us to a different plane, then messed up our seats. We chose seats together at booking and still lost our seats.