Pilotless Passenger aircraft won't happen in our lifetime. There are a lot of variables during takeoff that a computer cant handle that a pilot has handeled. I recall a 1900 that had a mis rigged elevator and the pilots aborted past v1... the computer would just keep trying to rotate until it ran full speed off the end of the runway. A computer can cruise and land, but takeoff I think will be trouble. Besides a pilot can handle hydraulic failures and flight control failures better than a computer. They can think and adapt while a computer can only do what it is programmed to do. A pilotless passenger jet is a very long ways off.