AA 2247 then AA 1918 at Miami
Boston → Miami → Chicago O'Hare
Timetable, Miami time
17:50AA 2247 from Boston at the gate
21:21AA 1918 to Chicago O'Hare leaves the gate
3 h 31 apart on the timetable
The last days
AA 2247 and AA 1918 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.