The technology to do this already exists today but it needs a lot of work and a huge amount of testing before we'll ever see it. The biggest obsticle is the communications link between the UAV and the ground *pilot*.
This data link must be fast enough to relay real-time video from at least 1 hull mounted camera, RT transmission and all the required flight data that will supply the 'virtual' cockpit on the ground. This datalink, which would need to provide at least 600kb/s of bandwidth can only be provided by a very expensive and less than 100% reliable satlink.
There is a company in Italy developing a UAV to carry 60kg of payload, it's use is reported to be within the commercial extreme urgent parcel sector.
Also, if you think about it, the UAV needs at least a pilot of some description on the ground plus a whole host of tech support guys, so is there really a significant cost saving to be had?
I don't think we'll see the first pax aircraft for an least 10 years.