Originally Posted by
ATOBTTR
I checked the Flight Status and all of the ATL-CUN departed from E/F but the first ATL-YYZ flight I checked today showed a departure from D, as did one other flight (the others left from E/F). One ATL-NAS flight left from D. So DL does send international flights out of other concourses though it does appear most tend to go out of E/F.
YYZ and NAS have pre-clearance. CUN does not. They can arrive and turn the YYZ and NAS flights from any old domestic gate. Can't do the same from CUN.