Separate tickets. Not the last UA flight of the day out of ORD, there are two more that day. Switching to AS for outbound so we don't have to reclear security. I recognized the risk in the tight connection and booking mediums of this trip but to me it was worth the ~2k saved in cost for flights. Thanks for the intel on needing to reclear if we use the ATS, that would be no fun. Also likely going to change the connection to something an hour later and just take a credit on UA for some future travel.