Have to agree with the above posts, but I feel your pain. An on time TVC flight is a rare event, and with only 2 a day off-peak, you have little choice but to take a Rule 240.

Bottom line is never trust a TVC flight, although AA is far better than UA. And to think that a best advance is near $400, with last minute at $800 + for 40 minutes and all the flights are full. Too many ORD folks buying second homes.