UA 3377 then AA 3297 at O'Hare
Pittsburgh → Chicago → Dallas-Fort Worth
Timetable, Chicago time
08:30UA 3377 from Pittsburgh at the gate
21:06AA 3297 to Dallas-Fort Worth leaves the gate
12 h 36 apart on the timetable
AA 3297 leaves 12 h 36 after UA 3377 arrives on the timetable: more than half a day, so not a connection we count.