M6 5778 then UA 1426 at Houston
Louisville → Houston → Merida
Timetable, Houston time
17:04M6 5778 from Louisville at the gate
16:44UA 1426 to Merida leaves the gate
23 h 40 apart on the timetable, overnight
UA 1426 leaves 23 h 40 after M6 5778 arrives on the timetable: more than half a day, so not a connection we count.