Created a Tractor with it's path to deliver steel 1000m away. Disappeared without a trace. No Icon, nothing.
Created a 2nd Tractor by following the same pathing. Disappeared without a trace. No icon, nothing.
Third Tractor disappeared...
Moved my oil tractor two steps without disabling autopilot, disappeared without a trace.
I dislike using conveyer belts for 1000m-2000m but I guess there's no alternative.
suggestion: when fuel runs out, disable autopilot to get the icon back and perhaps have a chance to recover the vehicle. I suspect they probably fell through the map.
update: After 40 hours I got the explorer upgrade and the map that shows one of the tractors to be in a place I have not yet discovered in a far off place.