UA 3901 then AA 2814 at San Francisco
Los Angeles → San Francisco → Chicago O'Hare
Timetable, San Francisco time
09:36UA 3901 from Los Angeles at the gate
09:12AA 2814 to Chicago O'Hare leaves the gatealso QF 4105
23 h 36 apart on the timetable, overnight
AA 2814 leaves 23 h 36 after UA 3901 arrives on the timetable: more than half a day, so not a connection we count.