I'm not sure passenger aircraft will ever become fully pilot-less.
I'm sure that with future advances in computer technology it would be technologically feasible to do it... but would it be worth it.
Quite simply, the major advantages of current automated aircraft are:
1: they can do dangerous things in dangerous places without risking a life
2: they can avoid the need to build in complex and expensive life support systems, pressurisation, etc etc.
3: the aircraft can be built to a shape or design purely focused on its intended mission, without the compromise of adding bits to look after humans.
Airliners have passengers and the systems to support them.. pressurisation etc etc.
In my opinion, none of those 3 advantages of automation apply to passenger aircraft because
1: passenger planes dont generally do dangerous things in dangerous places
2: they need those life support systems
3: the mission of these aircraft is passengers
Ok, yes, some might argue that it may in time be cheaper to automate things than have humans do it. But I'm not convinced the degree of investment required in all parts of the system, from aiports to aircraft to ATC etc etc would be cheaper than a couple of pilots in the front.
LP