People die in cars due to medical emergency all the time. I even know someone who had a heart attack and it caused him to hit a utility pole and die. We just don’t have any way of tracking it, whereas the FAA keeps very detailed statistics.

You’re leaving out the biggest risk: other people. Most deaths, in planes or cars, are caused by human error. In a car you’re dependent on everyone going down the road (and there may be thousands in one trip) not drifting across the median. You’re dependent on the person coming the other way at an intersection to stop. Etc.

Traffic deaths have been climbing again after decades of decline, probably due to distracted driving. Driving is much more dangerous.