While world leaders are at the UN talking climate change, their private jets are often forced to fly and park hundreds of miles away

• World leaders from across the globe flew into New York City to attend the United Nations General Assembly.
• Their aircraft, however, weren't allowed to stay at New York City's airports due to a long-standing rule.
• Boris Johnson took Amtrak's Acela from New York to Washington, DC while his plane was parked in Virginia.

New York City in September is a hotspot for world leaders as the United Nations holds its annual General Assembly. Climate change is a key topic at this year's conference, with leaders including President Joe Biden announcing additional investments in climate finance for developing countries.

But while leaders talk about commitments to climate change on the world stage, their government planes are burning extra jet fuel by flying empty to airports across the Northeast just to park during the event.

New York's JFK International Airport is the preferred gateway to the UN for many visiting countries due to its proximity to Manhattan. A long-standing rule of the Port Authority of New York and New Jersey, however, restricts those aircraft from staying at JFK while their passengers head to the UN.

Foreign military and state aircraft are barred from staying at Port Authority airports overnight due to traffic and space constraints, a spokesperson confirmed to Insider. After they've landed at a Port airport, those aircraft have two hours to depart for another airport where they'll park while in the US.

Commercial airports under the Port's purview also include LaGuardia and Newark Liberty International.

New York Stewart International Airport in Newburgh, New York, around 60 miles north of the UN, is a popular parking spot for foreign aircraft given its large runway and parking availability for large aircraft.

Flight tracking data shows that aircraft staying in Newburgh this year included a Boeing Business Jet 747-8i of the Turkish government, Airbus A319 of the Italian government, and Boeing 787-9 Dreamliner of Biman Bangladesh Airlines, among many others.

Aircraft will travel as far as Washington, DC, nearly 200 nautical miles south of New York, just for a parking spot.

Airports closer to New York including Farmingdale Republic Airport and Long Island MacArthur Airport are favorites of countries with smaller diplomatic aircraft. But larger aircraft, such as a Boeing 747, cannot use them or other nearby airports such as New Jersey's Teterboro Airport and White Plains, New York's Westchester County Airport due to runway constraints.

Foreign governments and militaries can request exemptions to the rule outside of UN week, the Port spokesperson told Insider, and an airport's general manager may grant it if traffic levels allow. Newburgh is a Port facility and exemptions are often made because of the airport's low traffic levels.

But during UN week, the aviation equivalent of tipping the valet extra to "keep it nearby" is considered bribery. Marlene Mizzi, a former assistant airport deputy supervisor at JFK, pleaded guilty in 2019 to accepting "benefits" for letting aircraft stay overnight during a session of the General Assembly.

Mizzi admitted to receiving " free limousine rides, meals, and gifts" in return for letting a Qatar state aircraft stay overnight in 2014, according to New York Attorney General Letitia James.

How the rule causes headaches for multi-stop US visits

UK Prime Minister Boris Johnson took to America's high-speed Amtrak Acela train to visit the White House while in the US. But Johnson's plane also made the trip to the nation's capital.

The UK version of Air Force One flew from New York to Washington Dulles International Airport in Virginia after dropping off Johnson on September 19. Had Johnson chose to fly between New York and Washington, his plane would have had to fly back to New York to pick him up, then fly back to Virginia to park.

And after Johnson's visit, the plane would have had to fly him back to New York, only to fly back to Virginia to park for the rest of the prime minister's UN visit, and then fly back to New York for the return flight to London.

A 2018 report from the International Council on Clean Transportation, an independent non-profit organization, found that aviation contributed to 2.4% of global carbon dioxide emissions. Even with the industry working towards a greener future, empty repositioning flights are still incredibly common for all aircraft operates.

The COVID-19 pandemic gave New York skies a reprieve as the General Assembly went virtual in 2020. But despite fears of the Delta variant, this year's in-person session pressed on and foreign leaders were ready to adopt "have plane, will travel."