UA 796 then AA 9782 at Boston
San Francisco → Boston → Chicago O'Hare
Timetable, Boston time
06:06UA 796 from San Francisco at the gate
11:00AA 9782 to Chicago O'Hare leaves the gate
4 h 54 apart on the timetable
The last days
UA 796 and AA 9782 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.