Note that the "Pilotless" aircraft now in use by the military still have Human operators. The major advantage over manned aircraft is their ability to loiter for long periods and the fact that they can undertake hazardous missions without risking a pilot.
They also need less redundancy, as a higher loss rate is acceptable- something that wouldn't be the case with a commercial (particularly passenger carrying) aircraft.
They are cost effective because they don't carry ANY Humans- if they did, the cost effectiveness would quickly diminish.
They still need controls and controllers, and as soon as you make a man-carrying craft- particularly a large one- it is probably actually MORE cost effective to have that controller strapped into the front of the machine.
I'd love it if pilotless aircraft became a reality- I often joke I hope to one day be able to work from home!!- but it's still long in the future.
Single pilot airliners on the other hand....