Letting in planeloads to be able to clamp down on the big shipments later seems plausible, especially if you follow the David Allen Coe Doctrine....."This will only hurt a little bit,........"
We did controlled deliveries for a living...we'd follow bad guys and go several layers deep so that we could protect operations and informants.
That said, you cannot allow the narcotics to end up on the street. That is a violation of U.S. law.
Also, the CIA mandate does not allow ops in the U.S. and it was their responsibility to inform the attache's office in South America of the loads...not ship them clandestinely so that they ended up in the hands of other criminals and ultimately users.
And finally, you'd have to believe that the ultimate intent was to bag bad guys down there as opposed to some other undisclosed (Iran-Contra type?) purpose.
If you ever watched the original Netflix show "Narcos", the portrayal of tension between CIA and DEA was real. Even some of the names of agents and cases involved. I know because I was involved in some of them,
Murky waters.
(The planeloads I was referring to was a 727 stretch set up for cargo. Not a small Cessna. Just for clarity's sake.)
This case also involved the Cuban government and smuggling, (which was not touched upon in the 60 Minutes story), and I was able to ferret out how the operation went through the island. When I brought in a Cuban official to provide information to the agency heads, the HQ bureaucrats decided not to pursue that avenue further. That failure ultimately led me to lose faith in my agency and its dedication to the mission, and ultimately why I left the service a few years earlier than mandatory.)