UA 3880 then UA 4040 at Houston
IAB → Houston → Atlanta
Timetable, Houston time
03:26UA 3880 from IAB at the gate
07:25UA 4040 to Atlanta leaves the gate
3 h 59 apart on the timetable
The last days
UA 3880 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.