These estimates vary quite a bit. Here's a 2023 paper in Nature studying climate impacts of various diets for people in the UK (not US): https://www.nature.com/articles/s43016-023-00795-w
Dietary impacts of vegans were 25.1% (95% uncertainty interval, 15.1–37.0%) of high meat-eaters (≥100 g total meat consumed per day) for greenhouse gas emissions
Vegans emit 2.16 kg/day while heavy meat eaters emit 7.28 kg/day of CO2 per this table.
600 kg for a round-trip cross-country flight seems about right, checking various city pairs on google flights. So here the estimate is more like 3x round trip flights. Other references I've seen make it closer to 1-1.5x. Actually if you choose the low meat eaters emissions from the same table (4.21 kg/day) that comes to 1-1.5x round trips.
These estimates vary quite a bit. Here's a 2023 paper in Nature studying climate impacts of various diets for people in the UK (not US): https://www.nature.com/articles/s43016-023-00795-w
Vegans emit 2.16 kg/day while heavy meat eaters emit 7.28 kg/day of CO2 per this table.
Heavy meat eaters: 7.28 kg/day * 365 days/year = 2657.2 kg/year
Vegans: 2.16 kg/day * 365 days/year = 788.4 kg/year
Difference: 1868.8 kg/year saved by going vegan
600 kg for a round-trip cross-country flight seems about right, checking various city pairs on google flights. So here the estimate is more like 3x round trip flights. Other references I've seen make it closer to 1-1.5x. Actually if you choose the low meat eaters emissions from the same table (4.21 kg/day) that comes to 1-1.5x round trips.