Welcome to FlyerTalk!
I'm not sure how a car can be safer, with any reasonable set of metrics. That being said, statistics can be manipulated a million ways, so get ready to read whatever you want in the numbers.
I think the "facts" are that more people die in cars than in planes over any given time period, and that there are dramatically more car "trips" than flights that happen per any given period - like many orders of magnitude. Based on that the number of deaths/trip is probably higher on planes than cars, but that doesn't make it more likely that you'll die in a plane than in a car.
The chances of having a fatal car crash or plane crash on any given day are very, very small. I can't tell you which one is safer than the other, but the odds of dying in either one are VERY small. That is a statistic that you can hang your hat on.
Oh, and there aren't too many places you can get to just by driving, at least not easily, so if you want to go on the trip the stats don't make much of a difference