DL 2743 then DL 543 at Atlanta
Tampa → Atlanta → St Louis
Timetable, Atlanta time
06:45DL 2743 from Tampa at the gate
15:45DL 543 to St Louis leaves the gate
9 h apart on the timetable
The last days
DL 2743 and DL 543 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.