If you want to be maximally pedantic, advanced autopilots are indeed capable of flying the plane by themselves. Modern commercial and military aircraft can take off, fly a route, and put the plane back on the ground, all by themselves. And autonomously flying a route is not unusual at all even in better-equipped small aircraft.

http://www.airliners.net/forum/viewtopic.php?t=1026435

Autoland has been around for more than 80 years and been used commercially for 60 of those.

https://en.wikipedia.org/wiki/Autoland.

It's pretty obvious what Tesla is getting at when they are advertising "every car sold with self-driving hardware".

The asterisk is of course that the hardware is self-driving capable, but the software isn't. But it's not hard to see where people are getting that idea from - it's Tesla's advertising and sales material.