Enplaned passengers on domestic flights - airlines in U.S. 2011-2021

371.1 million passengers boarded the listed U.S. airlines domestically in 2021, with the majority of enplaned passengers riding with Southwest Airlines, which had 120.7 million domestic enplanements in that year.  

Southwest Airlines: additional information

   Southwest Airlines was the airline with the most enplanements each year since 2011, with Delta Air Lines consistently coming in second until 2020 when American Airlines took the second spot. In 2021, Southwest Airlines had a customer satisfaction index score above the average for American airline companies. 

The worst year in air traffic

   Passenger air travel has been growing yearly since 2009, a trend estimated to continue through 2020 until the coronavirus pandemic happened, erasing two decades of passenger traffic growth in only a few months. This can also be seen in the number of domestic passenger enplanements on U.S. airlines - Southwest Airlines transported 58 percent less passengers in 2020 than it did in 2019.