People here seem not to realise that there are already today hundreds of aircrafts that fly day in day out pilotless. They are named drones, UAVs or UCAVs and you find them mostly over Afghanistan and/or Irak, with the pilots bunkered somewhere in Florida.
These aircrafts fly in and out without particular glitches and it is not out of the imagination that such technology be extended to civil aviation. In other words, that planes fly without a pilot on board, fly mostly based on automation with a remote pilot in a position to intervene in case required or for some specifically sensitive parts of flights.