AA 581 then 1I 511 at O'Hare
Miami → Chicago → St Louis
Timetable, Chicago time
09:30AA 581 from Miami at the gate
11:001I 511 to St Louis leaves the gate
1 h 30 apart on the timetable
The last days
AA 581 and 1I 511 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.