Everyone in these comments so far is misrepresenting the information here and arguing off of an incorrect assumption.
This is NOT saying that the 1% wealthiest people are responsible for half of these emissions. This is saying that 1% of travellers are responsible for half these emissions because those travelers travel so frequently. It has nothing to do with their wealth or using private jets. It's about how much they're flying.
Source: From the study linked in the petition: https://www.sciencedirect.com/science/article/pii/S0959378020307779
"1% of world population emits 50% of CO2 from commercial aviation." Not private jets. Commercial aviation.
"Data also supports that a minor share of air travelers is responsible for a large share of warming: The percentile of the most frequent fliers β at most 1% of the world population - likely accounts for more than half of the total emissions from passenger air travel."