According to Airports Council International (ACI) World,

Solution

The annual list of Busiest Airports in 2021 – compiled and released by Airports Council International (ACI) World. The world rankings, compiled every year, are based on global data that the ACI compiles as a trade association of all the airports. The up-to-date data includes passenger traffic as well as cargo volumes and aircraft movements. Eight of the 10 busiest airports in the world are based in the U.S.. The full list of the top 10 is below:

1. Atlanta (ATL)
2. Dallas Fort Worth (DFW)
3. Denver (DEN)
4. Chicago (ORD)
5. Los Angeles (LAX)
6. Charlotte, N.C. (CLT)
7. Orlando (MCO)
8. Guangzhou, China (CAN)
9. Chengdu, China (CTU)
10. Las Vegas (LAS)