AA 3740 then UA 5646 at O'Hare
Sioux Falls → Chicago → Richmond
Timetable, Chicago time
09:00AA 3740 from Sioux Falls at the gate
18:20UA 5646 to Richmond leaves the gate
9 h 20 apart on the timetable
The last days
AA 3740 and UA 5646 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.