UA 3911 then AA 879 at O'Hare
Portland (Oregon) → Chicago → Dallas-Fort Worth
Timetable, Chicago time
17:09UA 3911 from Portland (Oregon) at the gate
16:53AA 879 to Dallas-Fort Worth leaves the gate
23 h 44 apart on the timetable, overnight
AA 879 leaves 23 h 44 after UA 3911 arrives on the timetable: more than half a day, so not a connection we count.