AC 4121 then AA 2642 at San Francisco
Ontario → San Francisco → Chicago O'Hare
Timetable, San Francisco time
17:50AC 4121 from Ontario at the gate
15:18AA 2642 to Chicago O'Hare leaves the gatealso BA 5612, GF 6849
21 h 28 apart on the timetable, overnight
AA 2642 leaves 21 h 28 after AC 4121 arrives on the timetable: more than half a day, so not a connection we count.