AC 4121 then AA 2524 at San Francisco
Ontario → San Francisco → Chicago O'Hare
Timetable, San Francisco time
17:50AC 4121 from Ontario at the gate
15:04AA 2524 to Chicago O'Hare leaves the gatealso QF 4550, FJ 5015
21 h 14 apart on the timetable, overnight
AA 2524 leaves 21 h 14 after AC 4121 arrives on the timetable: more than half a day, so not a connection we count.