AA 2521 then AA 1974 at DFW
Calgary → Dallas-Fort Worth → Chicago O'Hare
Timetable, Dallas-Fort Worth time
11:00AA 2521 from Calgary at the gate
06:12AA 1974 to Chicago O'Hare leaves the gate
19 h 12 apart on the timetable, overnight
AA 1974 leaves 19 h 12 after AA 2521 arrives on the timetable: more than half a day, so not a connection we count.