Where the drones when you need them?
Sending a Predator missile from a drone would pretty much swat that mosquito out of the sky. That happens a couple dozen times, it would be hard to find prospective pilots to run this particular airlift.
Couple that with the basic sensor problem in distinguishing this near-vehicle like signature (radar and IR) further complicates the problem...follow a highway at 100 meters height until you get where you want to go sort of thing.
That said, this country will not authorize weapons use even if they should. They reserve that option for things like Ruby Ridge, Waco and other TBD options.
Technology is fungible. Pretty soon they'll be flying the drugs in with drones.