UA 3905 then UA 1024 at Houston
Cancún → Houston → Mexico City
Timetable, Houston time
13:29UA 3905 from Cancún at the gate
07:35UA 1024 to Mexico City leaves the gate
18 h 06 apart on the timetable, overnight
UA 1024 leaves 18 h 06 after UA 3905 arrives on the timetable: more than half a day, so not a connection we count.