evidence: In 1960, 100 million passengers traveled by air, at the time a relatively expensive mode of transportation available only to a small fraction of the public. By 2019, the total annual world-wide passenger count was 4.56 billion. The "hypermobility" of air travel is available to greater numbers of people worldwide, with rapid growth in aviation projected for developing nations and sustained growth in the large established aviation markets of developed countries. While our collective use of automobiles, our production of electricity, and the industrial and agricultural sectors each exceed the climate change impact of commercial aviation, passenger air travel was producing the highest and fastest growth of individual emissions before the pandemic, despite a significant improvement in efficiency of aircraft and flight operations over the last 60 years. [...] Although the FAA’s prediction for domestic U.S. passenger growth after traffic recovers to 2019 levels is modest (2.3 percent), the increase in actual numbers will nevertheless be significant. The sheer size of the mature U.S. air traffic system means even modest growth will generate an enormous increase in passenger traffic. By 2041, annual domestic enplanements in the United States are projected to reach 1.26 billion, 55 percent higher than in 2019. Total annual international passengers to and from the United States on American and foreign flag carriers should recover to pre-COVID levels by 2025 and climb from 67 million in 2020 to 446 million by 2041.