UA 3911 then AA 3585 at O'Hare
Portland (Oregon) → Chicago → Key West
Timetable, Chicago time
17:09UA 3911 from Portland (Oregon) at the gate
12:10AA 3585 to Key West leaves the gate
19 h 01 apart on the timetable, overnight
AA 3585 leaves 19 h 01 after UA 3911 arrives on the timetable: more than half a day, so not a connection we count.