There are different types of airports based on the type of activities that take place there. The most common type is the commercial airport. Commercial service airports are publicly owned airports with at least 2,500 passengers boarding every year. A commercial airport can either be a primary airport or a non-primary airport. The FAA differentiates primary and non-primary airports by the number of enplanements. A non-primary airport is an aerodrome with less than 10,000 passengers boarding each year. A primary airport is an aerodrome for passenger services with over 10,000 enplanements annually. A primary airport can be further broken down into four categories based on the share of overall passenger boardings: non hubs account for under 0.05 percent of the overall enplanements; small hubs - between 0.05 and 0.25 percent; medium hubs - between 0.25 and one percent; and large hubs account for over one percent of the total U.S. enplanements. Delaware is the only U.S. state without a primary airport.
The United States is home to some of the world’s busiest and most punctual airports. Atlanta’s Hartfield-Jackson International Airport handled close to 108 million passengers in 2018, making it the world’s busiest airport. It was also the second leading airport in terms of airport operations.
Chicago O’Hare International had the largest number of airport operations. With total operating revenue of over 903 million U.S. dollars, the airport is United’s main operating hub, handling some 10.54 million passengers from United’s flights in 2018. Los Angeles International Airport, colloquially know as LAX, was ranked third in airport operations. With around 319,000 flights arriving and departing, the airport 60.9 million domestic passengers and close to 26 million passengers on international flights in the fiscal year of 2018.