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).
You are correct and I thank you for the correction. The grand total miscalculates and mislead me. Also, wow, air travel is stunningly carbon expensive.
