AA 3818 then UA 644 at DFW
El Paso → Dallas-Fort Worth → Denver
Timetable, Dallas-Fort Worth time
15:45AA 3818 from El Paso at the gate
09:00UA 644 to Denver leaves the gate
17 h 15 apart on the timetable, overnight
UA 644 leaves 17 h 15 after AA 3818 arrives on the timetable: more than half a day, so not a connection we count.