Back in the 1970's TAN Airlines (TX) operated non stop service TGU-MEX-TGU on Lockheed L-188 Electra flights TX370/TX371 same days as AM nowdays: TUE/THU/SAT.
TX TGU-MEX in the 70s with Electra planes !
These route maps also showed TGU-ADZ-PTY, many years ago
TACA, SAHSA and LACSA utilized turbo-prop airplanes as cargo services, in the 70s and 80s.
During their early years, they transported passengers and then refurbished to cargo planes.
COPA also utilized turbo-props and jumped to the 737-200s in the early 80s, if I recall correctly.