I don't know that I agree. I'm not familiar with with aerospace software, but I see a lot of the user-facing bits of both automotive and medical devices/software. While the bits that are safety-critical may be rock solid (I've yet to see it fail in person), the UI design, maintenance, and UX in general leaves a lot to be desired.
For example, in my car, if the audio system is being driven from the bluetooth connection, you can't load the navigation screen. It will just spin forever. Switch to AM or FM radio, switch back to navigation, everything loads fine. How is that fantastic?
As another example, one of my doctors' office recently switched to using this big heavy cart thing for taking vitals measurements. The device is expensive, so they don't have nearly as many as they might have patients at one time, so I had to wait until one was free. The UI was slow and clunky (at best). To beat it all, the last time I was there all of the machines were shut down at the same time for scheduled updates (which was required to be done at a certain time, while the office was open), so it was back to the thermometer and blood pressure cuffs for me.