UA 503 then QF 7552 at O'Hare
Boston → Chicago → Los Angeles
Timetable, Chicago time
12:48UA 503 from Boston at the gate
18:50QF 7552 to Los Angeles leaves the gate
6 h 02 apart on the timetable
The last days
UA 503 and QF 7552 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.