Do note that that calculator uses different units for air travel and car travel. It uses MtCO2e for air and kgCO2e for car travel. When I went to the calculator I saw the same as you, but it turns out that with a few dozen flights a year that's still a few times the carbon (once converted to kg) generated by my electric vehicle (presumably from avg power plant emissions).

Given this data point about the average, it would be appropriate to establish, then, whether this individual has an above- or below-average footprint. This individual happens to have an extremely above-average usage of air travel, so it follows reason to not treat their usage as though "average" represents it accurately or could be used as a valid comparative reference.