UA 2340 then AA 3597 at O'Hare
Seattle (SEA) → Chicago → Huntsville
Timetable, Chicago time
20:40UA 2340 from Seattle (SEA) at the gate
19:51AA 3597 to Huntsville leaves the gate
23 h 11 apart on the timetable, overnight
AA 3597 leaves 23 h 11 after UA 2340 arrives on the timetable: more than half a day, so not a connection we count.