AA 1839 then AA 5418 at DFW
Washington National → Dallas-Fort Worth → Harlingen
Timetable, Dallas-Fort Worth time
09:37AA 1839 from Washington National at the gate
21:48AA 5418 to Harlingen leaves the gate
12 h 11 apart on the timetable
AA 5418 leaves 12 h 11 after AA 1839 arrives on the timetable: more than half a day, so not a connection we count.