UA 3913 then AA 3322 at Houston
Denver → Houston → Chicago
Timetable, Houston time
21:22UA 3913 from Denver at the gate
14:41AA 3322 to Chicago leaves the gate
17 h 19 apart on the timetable, overnight
AA 3322 leaves 17 h 19 after UA 3913 arrives on the timetable: more than half a day, so not a connection we count.