I agree that aviation also have to try to decrease emisions. Just... I am not sure about the CO2 tax. Can be only my subjective feeling but uder word "tax" I see increased costs for final user, but no control if money collected on that tax were used for something really helpfull.Even though I agree with you that there might be better ways to decrease the emissions, it is not that easy to just blame the other polluters and do nothing in the aviation. Every area should take its own responsibility and try to decrease the emissions. There are really no low hanging fruits that could decrease the emissions to the needed level. The concept of implementing the measures based on cost effectiveness is good but why should a power plant or industry take 100% of costs and aviation do nothing? The solution to this is to implement the CO2 tax on everything which will lead to the market implementing those solutions that are most cost-efficient. But I guess a 50$ CO2 tax on a kilo of beef will not be super popular in any country.
Same situation is with many projects... Sometimes governament spent a lot of money for "study" or some "concept" and result is.... nothing practical.
If there would be interest to start to use electric airplanes in aeroclubs and for training, lets support this with something simple. For example - no VAT or some other TAX on electric airplanes for aeroclubs. Simple, clear, helpfull