Back in my hardcore flying days on AA, I thought their boarding process was far less chaotic than UA. When I was CK (7 years), I got on the plane first most of the time and was escorted to my seat on the 10 or so international RT flights I took every year. Preboards were limited to CK, handicapped, and active military. Families with kids boarded with their normal group which really sped up the entire process - something I wish UA would adopt.. Preboarding literally just took a couple minutes - one or two CK, usually no military, and handicapped which could be a lot or a little. Preboarding on UA seems to take forever due to including 1K and families, and families with young kids (some of whom are clearly older than 2). When I was only an EXPLAT with AA, I boarded with group 1 along with those in F. That's all that was in group 1. When I stopped flying AA regularly and dropped to lifetime PLAT, I still boarded in Group 1 since I always purchased F (cash or miles). I have no specific numbers to back up my observations, but it appeared to me that there were far more GS and 1K (including me for a couple years) at UA than there were CK and EXPLAT at AA. I don't think that has changed based on what I see the handful of times I fly AA now. Often, the number of people I see in Group 1 on AA (including me) is less than the 1K preboards on UA on the same routes. No proof. Just an observation over many years. Now that you can in essence buy your way to EXPLAT on AA, perhaps the EXPLAT ranks will grow. But those buying their way to EXPLAT are likely not flying that much and so not clogging the gates like all the 1K preboards and their extended families.