M6 5778 then F9 2995 at Houston
Louisville → Houston → Denver
Timetable, Houston time
17:04M6 5778 from Louisville at the gate
21:43F9 2995 to Denver leaves the gate
4 h 39 apart on the timetable
The last days
M6 5778 and F9 2995 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.