Growth in aviation contributes more to global warming than is generally appreciated because of the mix of climate pollutants it generates: aviation contributed approximately 4% to observed human-induced global warming to date, despite being responsible for only 2.4% of global annual emissions of CO 2. Aviation is projected to have caused a total of about 0.1˚C of warming by 2050, half of it to date and the other half over the next three decades. Should aviation’s pre-COVID growth resume, the industry will contribute a 6-17% share to the remaining 0.3-0.8˚C to not exceed 1.5-2˚C of global warming. Under this scenario, the reduction due to COVID-19 to date is small and is projected to only delay aviation’s warming contribution by about 5 years. But the leveraging impact of growth also represents an opportunity: Aviation’s contribution to further warming would be immediately halted by either a sustained annual 2.5% decrease in flights under the existing fuel mix, or a transition to a 90% carbon-neutral fuel mix by 2050.