UA 3907 then UA 3919 at Houston
San Francisco → Houston → Newark
Timetable, Houston time
13:20UA 3907 from San Francisco at the gate
17:00UA 3919 to Newark leaves the gate
3 h 40 apart on the timetable
The last days
UA 3907 and UA 3919 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.