The safety assumption isn't exactly a given. The statistics cited represent passenger miles, not events. The formula is basically (passengers * trip miles)/deaths
Comparing automobile-related fatalities is challenging.
The standard comparisons given do not distinguish between passenger deaths and automobile-related deaths. 15-20% of all auto-related deaths are pedestrians and bicyclists. It also doesn't differentiate between trip types. Is there a difference between 24 hours driving from NYC to Miami via I-95 and 24 hours of driving within NYC? The published statistics do not speak to that.
I would conjecture if you were able to compare the relative dangers of inter-city interstate/freeway driving to a similar flight (including getting to/from the airport), you'd find that the safety gap was far narrower.
Also, lots of automobile fatalities are due to intoxicated drivers driving off the road, so if you don't drink and drive your odds get a whole lot better than the quoted statistics. And if I remember correctly, a large percentage of fatalities occur at intersections (especially left turns), so if you drive on highways you avoid those too.
The intoxication thing is another real issue with the stats.
Deaths get labeled as "alcohol related" and double counted all of the time. If I'm walking down the street drunk or riding in a cab drunk, that is tallied as an "alcohol related" crash.
I think in the uk the injury and fatality lists include those killed by a car not in it. Also the drunk drivers and drinkers hit by cars are not separated.
Comparing automobile-related fatalities is challenging.
The standard comparisons given do not distinguish between passenger deaths and automobile-related deaths. 15-20% of all auto-related deaths are pedestrians and bicyclists. It also doesn't differentiate between trip types. Is there a difference between 24 hours driving from NYC to Miami via I-95 and 24 hours of driving within NYC? The published statistics do not speak to that.
I would conjecture if you were able to compare the relative dangers of inter-city interstate/freeway driving to a similar flight (including getting to/from the airport), you'd find that the safety gap was far narrower.