The combined emissions from flying is about the same as the combined emissions from all cars in Sweden. Around 80% of all flying is private, 20% business. 20% of the population is responsible for 50% of the flying. Each flight is a relatively large part of a person's combined CO2 emissions, and it's pretty easy to not do it, compared to getting to work or eating food. That's why it's a pretty big deal.

As for Greta, all she's saying is that politicians should listen to the scientists and implement policies accordingly.