Earlier quoted context omitted.
There were a study done in Sweden a few years ago that looked at the question about an individuals actions and the corresponding CO2 production. No car > skipping flight > buy green energy > Get a electric car > diet. https://www.lunduniversity.lu.se/article/four-lifestyle-choi...
How does this differ if the majority of your electricity is zero carbon? Coal electricity is 60% of emissions. Aviation is less than 5%. How is skipping a flight that highly ranked of you are burning a ton of carbon just being at home (if you have coal fired power). Actual rankings have to be energy mix dependent.
So even though aviation is a small part of it all, it is one of the individual actions able to have outsized impact, usually for leisure or at least often for non-essential reasons.