IF there is anything to the idea that changes in the stratosphere are affecting Earth’s climate in a negative way (and I don’t say that’s true, I just said, “if”) - then jet transport aircraft exhaust is my #1 candidate for causation.
My candidate would be volcanic eruption.
I say this because a friend of mine from our time at Keesler Airforce Base later ran the meteorological computers at Tinker Airforce base for a decade and a half.
The Ozone layer thins when volcanoes erupt chlorine compounds into the upper atmosphere.
SUN
If you burn a gallon of any of them you will produce about 20 lbs of CO2 because the oxygen has a molecular weight of 16 and there are 2 oxygens plus the single carbon with a molecular weight of 12. Combustion is oxidation so the weight comes mainly from the oxygen.
The other byproduct of combustion is water, H20. Hydrogen has a molecular weight of one and there are two of them but the oxygen is 16.
So there is not a lot of difference in the CO2 produced from gasoline, diesel, or jet fuel.
The two biggest sources of CO2 are the tailpipes of autos/pickups and power plants so those are where most of the effort is in reducing CO2.
But of course jet aircraft does produce CO2, just not nearly as much as automobiles. Excluding military, most of jet aircraft miles is the mass market and the private market is relatively small.
In the mass market the main source of CO2 is the short hop flights like Dallas to Houston and LA to Frisco because they burn most of the fuel to reach altitude.
I'm not accusing any of you of being global warming fanatics but if you wanted to reduce aircraft emissions of CO2 you should promote high speed rail to replace short hop air flights.