DL 1091 then UA 1665 at San Francisco
Salt Lake City → San Francisco → Boston
Timetable, San Francisco time
23:59DL 1091 from Salt Lake City at the gatealso VS 4542
23:20UA 1665 to Boston leaves the gatealso VA 8306, NZ 9018
23 h 21 apart on the timetable, overnight
UA 1665 leaves 23 h 21 after DL 1091 arrives on the timetable: more than half a day, so not a connection we count.