UA 5559 then AA 1408 at DFW
Chicago O'Hare → Dallas-Fort Worth → Huatulco
Timetable, Dallas-Fort Worth time
16:29UA 5559 from Chicago O'Hare at the gate
10:49AA 1408 to Huatulco leaves the gate
18 h 20 apart on the timetable, overnight
AA 1408 leaves 18 h 20 after UA 5559 arrives on the timetable: more than half a day, so not a connection we count.