Aviation only makes up about 2% of total global C02 emissions. Hardly even worth worrying about. Results will be much better if resources are focused on the big emitters (road transport, electricity/heating, and manufacturing).
It's getting ridiculous; everybody is shifting blame to something or someone else because we all think small chunks and, obviously, each one of those chunks, individually, doesn't contribute much in terms of percentages. If you think this way, nobody will ever get anything done.
Because the majority of humanity has never flown at all. What fraction of your CO2 emissions came from flying last year?
I took 6 flights (~3,000km each).
I would start with the immediate implementation of a tax (10%?, 20%?) on all new ICE vehicle sales. Revenue from this tax would be used to subsidize the purchase of EVs.
I looked up one of my flights (actually only about 2,400km) using that calculator and only got 230kg (83kg of C02 and 173kg of "contrails, ozone formations, etc."). This flight was on a A321neo.