It was obviously an ultralight, but how do we know it wasn't converted an an unmanned vehicle. I can't imagine it would be hard to convert one to use radio controlled servos. Not having a pilot would free up a lot of weight for the shipment. The shipments they talk about are 250lbs, which is the same as the regulated amount ultralights are allowed to carry. The cartels wouldn't care about the regulations, obviously, but they would care about not over-stressing the engineering limits of the aircraft which would risk losing $400k to $16M in product (if the article is correct) if it crashed.