UA 654 then UA 3900 at Houston
Los Angeles → Houston → Washington
Timetable, Houston time
11:08UA 654 from Los Angeles at the gate
15:00UA 3900 to Washington leaves the gate
3 h 52 apart on the timetable
The last days
UA 654 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.