AM 4431 then UA 1665 at San Francisco
Los Angeles → San Francisco → Boston
Timetable, San Francisco time
23:21AM 4431 from Los Angeles at the gate
23:20UA 1665 to Boston leaves the gatealso VA 8306, NZ 9018
23 h 59 apart on the timetable, overnight
UA 1665 leaves 23 h 59 after AM 4431 arrives on the timetable: more than half a day, so not a connection we count.