Golf_Sierra
I would assume that the airframe itself in drones is fairly conservative, hence relatively inexpensive which makes the whole thing expendable. Maybe that is one of the advantages the remote technology offers - you can really push it to the limits since you don't have to worry about the human pilot aboard. And since you don't engineer it to carry a human it is much cheaper. You produce many airframes and then just tweak the software - so it is possible to test many solutions in parallel.
The airframe, avionics and engine of a UAS are built to meet the UAS requirement. Some are effectively lawnmower engine driven with simple COTS OEM computer parts with robbed parts of cell phones. They are good enough to meet the customers' specs. The very fact that they do not have to meet the demands of safety for a pilot reduces the reliability demands. They are then used in battlespaces where some are seen as almost disposable items. Comparing their reliability to an aircraft that meets 14 CFR part 23 or 91 or whatever is a meaningless exercise.
However, as they start to be used for civil applications in normal domestic environments safety of the people below them on the ground demands that they cannot be allowed to have high failure rates, have control links that drop out or can be hacked etc. Therefore, new Minimum Aviation System Performance Standards for UAS are being developed and expect both FAA and EASA to impose them in the next two or three years.
There
are already passenger carrying UAS - Boeing Little Bird for example. There will be more in the years to come. These UAS will need to be certified to the same level as manned passenger carrying aircraft (unless they are government owned).
To Flexiflyer,
As for single crew, what happens if this person flips out. Didn't this happen on a Fedex aircraft some years ago? What happens if they become incapacitated for whatever reason.
As the intentional crash of the Egyptair aircraft showed, there is nothing really different with manned aircraft except in the 'manned UAS' case the ground control can take over direct control of the aircraft. The pilot could be seen to be what is currently called a 'cruise pilot' only there to tend the automation in cruise flight - or alternatively - the automation could be seen as the 'cruise pilot' and the pilot be there as the 'captain' to handle exceptions. But in both cases there would be pilots on the ground who can take over remotely.