UA 1275 then DL 2640 at LAX
Cancún → Los Angeles → Seattle (SEA)
Timetable, Los Angeles time
17:34UA 1275 from Cancún at the gate
17:15DL 2640 to Seattle (SEA) leaves the gate
23 h 41 apart on the timetable, overnight
DL 2640 leaves 23 h 41 after UA 1275 arrives on the timetable: more than half a day, so not a connection we count.