AA 3091 then UA 779 at Denver
Kansas City → Denver → Boston
Timetable, Denver time
12:24AA 3091 from Kansas City at the gate
16:01UA 779 to Boston leaves the gate
3 h 37 apart on the timetable
The last days
AA 3091 and UA 779 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.