AA 1253 then UA 1284 at San Francisco
Chicago O'Hare → San Francisco → Newark
Timetable, San Francisco time
09:40AA 1253 from Chicago O'Hare at the gatealso QF 4697
14:00UA 1284 to Newark leaves the gate
4 h 20 apart on the timetable
The last days
AA 1253 and UA 1284 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.