UA 1590 then AA 1408 at DFW
Newark → Dallas-Fort Worth → Huatulco
Timetable, Dallas-Fort Worth time
18:32UA 1590 from Newark at the gate
10:23AA 1408 to Huatulco leaves the gate
15 h 51 apart on the timetable, overnight
AA 1408 leaves 15 h 51 after UA 1590 arrives on the timetable: more than half a day, so not a connection we count.