UA 3903 then AA 2663 at San Francisco
Seoul → San Francisco → Philadelphia
Timetable, San Francisco time
08:46UA 3903 from Seoul at the gate
23:59AA 2663 to Philadelphia leaves the gatealso EI 7356
15 h 13 apart on the timetable
AA 2663 leaves 15 h 13 after UA 3903 arrives on the timetable: more than half a day, so not a connection we count.