UA 3890 then UA 4040 at Houston
Amarillo → Houston → Atlanta
Timetable, Houston time
01:28UA 3890 from Amarillo at the gate
07:25UA 4040 to Atlanta leaves the gate
5 h 57 apart on the timetable
The last days
UA 3890 and UA 4040 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.