AA 2437 then UA 3998 at Charlotte
Pittsburgh → Charlotte → Washington
Timetable, Charlotte time
06:39AA 2437 from Pittsburgh at the gate
19:55UA 3998 to Washington leaves the gate
13 h 16 apart on the timetable
UA 3998 leaves 13 h 16 after AA 2437 arrives on the timetable: more than half a day, so not a connection we count.