UA 3988 then AA 1452 at Charlotte
Houston → Charlotte → Chicago O'Hare
Timetable, Charlotte time
10:49UA 3988 from Houston at the gate
14:58AA 1452 to Chicago O'Hare leaves the gate
4 h 09 apart on the timetable
The last days
UA 3988 and AA 1452 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.