This becomes more tricky.

You must see that the place where the gases are emitted matters to. Planes just on the worst place. CO2 is heavier then common air.

I ride my bicycle. This is optimum solution. Much faster then walking. Small footprint in production. Small CO2 emission, all regenerative. I have not seen a plane from inside for a decade or so.

Update:

Maybe you should compare with other public transport systems like train or bus instead individual transport.

>How does that compare to the greenhouse gases if all passengers on a single plane were driving in autos instead?
>
>>Agnes,
>>
>>I didn't check the atom balance, good catch. But the CO2 balance is correct and that's all that's relevant in this case. Agreed that the 4.0L/km/passenger average might be off by a few percent if it's weighted more on longer range flights. But Airbus claims much better fuel economy so I stuck with the more conservative value.
>>
>>>>kerosene combustion reaction: C12H28 + 37/2 O2 -> 12C02 + 13H20
>>>
>>>where is the single H2 where do you get a half O2?
>>>
>>>28 Atoms H on the left does not equal 13H2 equal 26 Atoms on the right
>>>
>>>it must be
>>>
>>>C12H28 + 37/2 O2 -> 12C02 + 13H20 +H2
>>>
>>>but this sounds not likely, why shouldn't the free H2 not react? If there is not enough oxygene I always thought it would react with the hydrogen rather then carbon.
>>>
>>>or
>>>
>>>C12H28 + 19 O2 -> 12C02 + 14H20
>>>
>>>If you use a more complex equation where the H2 goes to something else you need to put this into the equation and its remnants into acount to the rest of your view.
>>>
>>>Short range flights consume more fuel then average. No idea how much. But just consider the repeated acceleration, climbing and lower flight altitude.
>>>
>>>Universe is non linear.