UA 6138 then AA 3294 at Charlotte
Houston → Charlotte → Boston
Timetable, Charlotte time
15:54UA 6138 from Houston at the gate
15:19AA 3294 to Boston leaves the gate
23 h 25 apart on the timetable, overnight
AA 3294 leaves 23 h 25 after UA 6138 arrives on the timetable: more than half a day, so not a connection we count.