Newark Liberty International Airport, originally Newark Metropolitan Airport and later Newark International Airport, is the primary airport serving the U.S. state of New Jersey. The airport straddles the boundary between the cities of Elizabeth and Newark, the latter of which is the most populous city in the state. The airport is owned jointly by the cities of Elizabeth and Newark and leased to and operated by the Port Authority of New York and New Jersey.Newark Airport is located 60 miles northeast of Philadelphia, and 15 miles southwest of New York City, and is a major airport serving both the New York and Philadelphia metropolitan areas. It was the first major airport in the United States and was the Northeast USA's busiest in terms of flights through 2013.The airports in the New York metropolitan area, including Newark Airport, combine to create the largest airport system in the United States, the second-largest in the world in terms of passenger traffic and largest in the world in terms of total flight operations. In 2015, Newark Airport handled 37.5 million passengers, JFK handled 56.8 million, and LaGuardia handled 28.4 million. In 2016, Newark served a record 40 million passengers.