UA 1327 then AA 2579 at Denver
Tucson → Denver → Dallas-Fort Worth
Timetable, Denver time
08:27UA 1327 from Tucson at the gate
13:13AA 2579 to Dallas-Fort Worth leaves the gate
4 h 46 apart on the timetable
The last days
UA 1327 and AA 2579 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.