WN 645 then AA 3544 at Detroit
St Louis → Detroit → Chicago O'Hare
Timetable, Detroit time
12:50WN 645 from St Louis at the gate
16:28AA 3544 to Chicago O'Hare leaves the gate
3 h 38 apart on the timetable
The last days
WN 645 and AA 3544 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.