My definition of payload is something that the vehicle is a carrying, that is not part of the vehicle itself. In other words, something being transported which is placed onto/into and then offloaded at some point. A navigational component is an inherent part of the vehicle itself. But a person, missile or bomb are not, so a drone so-equipped with releasable weapons could be called a vehicle by definition.

Personally, I avoid calling anything a vehicle that cannot carry one or more persons. It makes it simpler.

Anyway, time to hop on my car to go make a hook up in the airport at the plane.