Newark Liberty International Airport is an airport of firsts: the first major airport in the New York metropolitan area, the first with a control tower and now the area's busiest. Sandwiched between the New Jersey Turnpike, U.S. Routes 1 and 9, and I-78, the airport handles more flights (though not as many passengers) than John F. Kennedy International Airport (JFK), despite being 40 percent of JFK's land size. The airport serves as a hub for United Airlines, among 50 other scheduled carriers. The City of Newark built the airport on 68 acres (28 ha) of marshland in 1928 and the Army Air Corps operated the facility during World War II. After the Port Authority took it over in 1948, an instrument runway, a terminal building, a control tower and an air cargo center were added. The airport's original 1935 central terminal building is a National Historic Landmark. Newark Liberty employs more than 24,000 people.
In 2017, EWR was the sixth busiest airport in the United States by international passenger traffic and fifteenth busiest airport in the country. It served 43,393,499 passengers in 2017, which made EWR the forty-third busiest airport in the world by passenger traffic. In 2018, the airport saw 46,065,175 passengers, the most in its history.
Newark serves 50 carriers and is the third-largest hub (after Chicago–O'Hare and Houston–Intercontinental) for United Airlines, which is the airport's largest tenant (operating in all three of Newark's terminals). Newark's second-largest tenant is FedEx Express, whose third-largest cargo hub uses three buildings on two million square feet of airport property. During the 12-month period ending in July 2014, over 68% of all passengers at the airport were carried by United Airlines.