> Use a weather balloon or rocket or something and go high on the Mexican side.
High is visible and traceable. Unpowered glide is also traceable. Anything which stays in view too long is going to get filmed with by someone with a cellphone and a GPS. Low and fast wins.
You want to stay low and cover a long curved path (preferably whose radius changes) so that the release of the payload is invisible and really hard to trace (a 40 mile path over a sparsely populated forest would be really hard to track).
> so this must be used or not have enough payload capacity to make it more profitable than other methods
I suspect more profitable is the answer to why it isn't done. Why pay $10,000 for a drone when you can pay $5,000 for a human mule that you need at either end anyhow?
High is visible and traceable. Unpowered glide is also traceable. Anything which stays in view too long is going to get filmed with by someone with a cellphone and a GPS. Low and fast wins.
You want to stay low and cover a long curved path (preferably whose radius changes) so that the release of the payload is invisible and really hard to trace (a 40 mile path over a sparsely populated forest would be really hard to track).
> so this must be used or not have enough payload capacity to make it more profitable than other methods
I suspect more profitable is the answer to why it isn't done. Why pay $10,000 for a drone when you can pay $5,000 for a human mule that you need at either end anyhow?