UA 3903 then UA 235 at San Francisco
Seoul → San Francisco → Houston
Timetable, San Francisco time
08:46UA 3903 from Seoul at the gate
18:00UA 235 to Houston leaves the gate
9 h 14 apart on the timetable
The last days
UA 3903 and UA 235 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.