Bottom line is there will be pilotless passenger aircraft in the next 20 years.
There is absolutely zero chance of that. Even the latest generation aircraft such as the 777 X, which has a projected entry into service towards the end of the decade, and a typical service life of 20 years plus, still has 2 pilot seats, let alone none!
Do some more research on the number of drone crashes in the USA and you will realise that the reliability is nowhere near a level acceptable to the travelling public. Here's one link:
Crashes mount as military flies more drones in U.S. | The Washington Post
Bear in mind that drones are RPVs - remote piloted vehicles, where the pilot has not been eliminated, but simply moved to a ground station out of harms way.
WRT to automation things are actually moving in the opposite direction with the realisation that automation has progressed to the point that the pilot either does not understand what the aircraft is doing, or when things go wrong (as they do), the pilot is out of the loop - hence the Boeing philosophy of keeping the pilot in the loop (thrust levers that move with the auto-throttle, manually setting the track bug, control column as opposed to side stick etc.). Even Airbus is recognising this; the first couple of days of A350 training consists of manual handling with all the automatics turned off.
I honestly do not think that fully automated passenger aircraft will ever be a reality - first of all it would not be practical (the pilot's not only fly the aircraft, but manage the aircraft - dealing with passengers issues, dispatch issues, assessing DDG issues, de-icing decisions and monitoring, making refuelling decisions, weather decisions, managing diversions etc.). Secondly I don't think it could ever be achieved with an acceptable level of safety.
Of course it is technically possible - in fact a fully automated flight is mostly possible now, apart from taxying and takeoff, but in the real world aircraft very seldom follow a pre-programmed route. We seldom do an autoland, and many of the airports we fly to or use as alternates do not support Cat 3B approaches . Even if they do, the ILS would have to be protected to allow for an auto-land, requiring much greater traffic separation and reducing capacity - completely unfeasible at airports such as Heathrow that would be gridlocked as a result.
Remember 95% of the training airline pilots do in simulators is not for the normal day to day operation where things are going swimmingly, but for when things don't follow the script - this is where automation falls down badly and where pilots really earn their salaries.
Automation is great for flying CPDLC across the Pacific (most of the time), but as good as useless for managing an approach into Chicago ORD during busy periods, especially with weather.
How would you automate a flight over the Himalayas that requires constant assessment of alternates and escape routes, and where a depressurisation or engine failure would necessitate a diversion along an escape route to a possibly minimally equipped airport? What about a rejected take-off due to a runway incursion? TCAS avoidance that requires the auto-pilot and auto-throttle to be disconnected? Ditto for unreliable airspeed..
Automating weather avoidance would be virtually impossible since the weather radar requires a lot of interpretation, and then the required avoidance has to be co-ordinated with ATC, taking into account the required flight path.
Furthermore you would just be replacing the pilots in the aircraft with ones on the ground, but with much greater technical sophistication and associated cost. The bottom line is that by far the highest cost is fuel - the savings achieved by eliminating the pilots would be more than offset by the cost of the increased technical sophistication and the additional ground personnel required.
A number of the recent accidents resulted from the failure of auto-flight systems (think Turkish airlines and AF447), but could have been prevented if the flight crew had responded adequately. If you look at the Boeing service bulletins, the majority of them relate to anomalies in the auto-flight system that in most cases came to light many years after the aircraft was certified. Some of them are quite serious (such as dual FMC failures in the case of the 777), and could have been catastrophic if there hadn't been a flight crew there to take over and fly the aircraft manually.
Most pilots of modern fly by wire aircraft have seen the automatics do some very strange things - in some cases requiring a disconnect and reversion to manual flight. Ever watched a 777 attempt an alt capture with a high rate of climb accompanied by an increasing tailwind? Guaranteed low airspeed situation.
Lastly, who will be the first manufacturer to invest billions in developing an aircraft that in all likelihood would be shunned by passengers - I know I wouldn't fly in it!