UA 3879 then DL 1998 at Miami
Chicago O'Hare → Miami → New York LaGuardia
Timetable, Miami time
01:43UA 3879 from Chicago O'Hare at the gate
11:25DL 1998 to New York LaGuardia leaves the gate
9 h 42 apart on the timetable
The last days
UA 3879 and DL 1998 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.