DL 1909 then DL 4925 at JFK
Salt Lake City → New York → Chicago O'Hare
Timetable, New York time
05:00DL 1909 from Salt Lake City at the gate
07:30DL 4925 to Chicago O'Hare leaves the gate
2 h 30 apart on the timetable
The last days
DL 1909 and DL 4925 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.