OZ 304 then UA 3900 at Incheon
Changchun → Seoul → San Francisco
Timetable, Seoul time
14:30OZ 304 from Changchun at the gate
19:30UA 3900 to San Francisco leaves the gate
5 h apart on the timetable
The last days
OZ 304 and UA 3900 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.