AA 4504 then UA 5789 at O'Hare
South Bend → Chicago → San Antonio
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
13:30UA 5789 to San Antonio leaves the gate
18 h 55 apart on the timetable, overnight
UA 5789 leaves 18 h 55 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.