UA 503 then H2 4920 at O'Hare
Boston → Chicago → Milwaukee
Timetable, Chicago time
12:48UA 503 from Boston at the gate
13:33H2 4920 to Milwaukee leaves the gate
45 min apart on the timetable
The last days
UA 503 and H2 4920 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.