AA's model for many years has been to bank their hubs, which means many flights arriving in small windows throughout the day. In a perfect world, that means most passengers can connect quickly from one flight to the next. And while delays are obviously a concern, delays might expect to impact both connecting flights, at least in theory, which would prevent passengers from being delayed.

AA does expect you to be able to make your 30-minute (or 40-minute, or however long) connection the vast majority of the time.