WN 3774 then DL 776 at Miami
Austin → Miami → Boston
Timetable, Miami time
13:00WN 3774 from Austin at the gate
19:59DL 776 to Boston leaves the gate
6 h 59 apart on the timetable
The last days
WN 3774 and DL 776 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.