The Port Authority of New York and New Jersey wants to divert some of the air traffic in New York City’s overcrowded skies to Stewart International Airport in New Windsor, N.Y.

Crain’s New York Business reports today that the Port Authority aims to partner with the private transportation company that runs Stewart, National Express Group, to direct some of the city’s air traffic to the airport.

The three major airports that serve New York face overcrowding in the near future, with passenger traffic expected to grow by at least 40% in the next 10 years, Crain’s reports. The airports are already operating at or near capacity. A quarter of the passengers who travel through the three major airports, which the Port Authority controls, face delays of an average of 50 minutes, Crain’s said.

“Our ability to expand capacity at these airports is critical for the region’s economic success,” the Crain’s article quotes the chairman of the authority, Anthony Coscia, as saying.

Only John F. Kennedy International Airport, which sits on nearly 5,000 acres, has room to expand. La Guardia and Newark Liberty International airports are blocked in. Stewart International Airport, which currently serves Westchester, Duchess, and other counties, in June announced a 20-year, $490 million capital improvement plan to build a new passenger terminal, new taxiways, and a runway extension. The plan also includes direct access to Interstate Highway 84 and a Metro-North commuter rail extension connecting to the Port Jervis Line.

The Transportation Equity Act, which President Bush signed into law in August, earmarked $100 million to finance a rail link to the airport. There are several rail stations nearby, but none connects directly to the airport.

Stewart International sits on more than 2,220 acres. At present it has two runways: One is 6,006 feet long and the other, at 11,818 feet, is one of the longest on the East Coast. Previously an Air Force base, Stewart International became America’s first commercial airport to be privatized, in 2000.

In addition to courting Stewart International, the Port Authority is negotiating with several other regional airports and researching locations for a possible fourth airport to serve the city, the Crain’s article said. The authority expects to release the results of a $50,000 study of sites in New York, New Jersey, and Connecticut early next year. The city’s three major airports handled 1.1 million domestic and international flights in 2004, carrying 93.9 million passengers and 3 million tons of cargo, the Port Authority said in a report released in October. These numbers account for 12.2% of America’s total aviation passenger traffic and 14.4% of the nation’s air cargo volume, the report said. A spokesman for the Port Authority, Steve Coleman, referred a reporter to the authority’s chairman, Anthony Coscia, who was not available to comment on the Crain’s article.