The idea that there can be a sensible coloration between current UAVs and future Pilotless airliners is a little weak.
UAVs are not pilotless per se, they are remotely piloted. In addition carrying only hardware rather than "software" people, the loss of a UAV is only monetary.
At the moment there is no such thing as 100% safe software, indeed all our FBW aircraft have redundancy in spades but still need the Mk1 eyeball and Human interface in some situations.
When the Military go pilotless for combat aircraft the civil world will follow probably a decade later. IMHO.