This Our World In Data article on Climate Change and Flying reports that global aviation, before the pandemic, was responsible for only 2.5% of CO2 emissions.
At first appearance that seems like a small number that may not justify all the investments in new technologies, or in reduction of travel, to have much of an impact in arresting climate change. But the challenge with decarbonizing the global economy is that most sources of GHG by industry are in the single digits!
So we have to make progress in each and every sector; no small change is too small as they will all add up.
Learn more at https://ourworldindata.org/co2-emissions-from-aviation.