Whilst I full understand the important distinction between autonomous and remotely piloted aircraft, I would point out that any autonomous aircraft operating in an air traffic environment like the one we have currently will have to allow remote access to its FMS. This is the only way that route changes and other ATC constraints can be conveyed. Therefore many of the concerns regarding hacking into the system remain valid.
Only when we have an air traffic environment where the aircraft can autonomously self separate (in an orderly way which never creates escalating knock-on effects) can we really consider one where the they can autonomously navigate.
So basically the ATCos are all going to be out of work before the pilots.
[Sorry if this has already come up. This thread got too big too quickly for a newcomer to have a hope of reading the whole thing before posting.]