MGR,
One San Juan airport expert said "It would be the "US Mail' "Air Express" and "AM-xxx" which is Air Mail Route with the Route Number for Caribair.".
The other San Juan airport expert said "The bottom line is probably the Air Mail Route number, 'AM XX' In Caribair's case I would assume that it was the Air Mail route between San Juan and St. Thomas/St. Croix, since those were the 'domestic' routes that they flew."
I am waiting for other San Juan airport experts to answer my question.
Regards,
Aharon
One San Juan airport expert said "It would be the "US Mail' "Air Express" and "AM-xxx" which is Air Mail Route with the Route Number for Caribair.".
The other San Juan airport expert said "The bottom line is probably the Air Mail Route number, 'AM XX' In Caribair's case I would assume that it was the Air Mail route between San Juan and St. Thomas/St. Croix, since those were the 'domestic' routes that they flew."
I am waiting for other San Juan airport experts to answer my question.
Regards,
Aharon