In 2018, the total number of air passengers increased in the US, with some periods of the year experiencing all-time high air travel volumes. Around the world, airlines carried 4.3 billion passengers in 2018, an increase of 38 million compared to the year before. Aviation accounts for about 2 percent of global greenhouse gas emissions, and that share is poised to grow.
The International Civil Aviation Organization anticipates that by 2020, global international aviation emissions are projected will be 70 percent greater than in 2005. By the middle of the century, they are slated to increase by upward of 700 percent. Every round-trip trans-Atlantic flight emits enough carbon dioxide to melt 30 square feet of Arctic sea ice.https://www.vox.com/energy-and-environment/2019/1/11/18177118/airlines-climate-change-emissions-travel