UA 2153 then AA 9951 at O'Hare
Richmond → Chicago → Charlotte
Timetable, Chicago time
07:42UA 2153 from Richmond at the gate
12:00AA 9951 to Charlotte leaves the gate
4 h 18 apart on the timetable
The last days
UA 2153 and AA 9951 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.