New York's perennially overcrowded airports could be busier. Unlike their peers across the Atlantic, airlines only have to use 80% of their allotted operating authorisations - or slots - at JFK, LaGuardia and Newark. Just imagine the possible congestion.
A recent US Government Accountability Office report looking into the slots issue found delays of more than 15 minutes jumped to 330 per day at LaGuardia in October 2000 after slot restrictions were eased that year. Delays fell to 98 per day in April 2001 after the US FAA reinstituted the operational restrictions.
Susan Baer, aviation director at the Port Authority of New York and New Jersey, says she would like the number of slots airlines have to use to be "a little higher", despite the potential impact on operations. While that decision rests with the federal government, the authority under her leadership is tackling the issue of congestion and expansion every way it can.
The authority oversees JFK, LaGuardia, Newark, Stewart airport - 100km (60 miles) north of New York city - and general aviation facility Teterboro. Combined, the three core commercial airports were the busiest in terms of passenger boardings (105.5 million) and movements (1.2 million) in the USA in 2011, Airports Council International - North America (ACI-NA) data show.
The authority must work closely with airlines and the FAA to keep its airports running smoothly. It does an "excellent job" at this, says Deborah McElroy, executive vice-president of policy and external affairs at the ACI-NA. She explains it has developed a clear role for each airport - international travel at JFK, business at LaGuardia and a combination of the two at Newark - and works with carriers to drive traffic to the appropriate facility.
"There's pressure on the system, which forces people to be more creative and more resourceful about how you manage that capacity," says Baer. Although slots do a lot to manage congestion at the airports, she says the authority's delay task force continually recommends ways to improve efficiency, such as high-speed taxiways, additional air- craft holding pads and metering.
"We can say: 'This [recommendation] will improve delays by eight seconds per aircraft' and I get this eye-roll," she says. "But start adding all of those together, they come up with a major improvement."
One of the big changes in recent years was the aircraft-metering programme at JFK. Implemented three years ago during a runway-resurfacing project, aircraft were held at their gate until a few minutes before their departure. The programme was a success, Baer says, saving five million gallons of fuel and 15,000h of taxi time during its first year.
The programme will be implemented at LaGuardia and Newark, pending availability of the necessary flow-rate data from the FAA in 2013, says Baer.
The authority is also focused on growth. It bought Stewart in 2007 from a private consortium and will use it as a "release valve" for the region's other airports in the future, says Baer. At the same time, it is looking at ways to expand JFK, LaGuardia and Newark, despite high hurdles.
"We are doing a very intensive study about where we can pour more concrete at our airports, where we can add additional capacity," says Baer. Whatever recommendations are made will carry a high cost and face significant scrutiny from nearby residents.
When it comes to operating a multiple airport system, Baer has a few words of wisdom: "If you're going to run an airport system, you should run an airport system. You should be consistent across the board. If we've figured out the best way to do something at one airport, we should be doing that at all five."
Could London's capacity-constrained airports learn from the New York approach? "[London's] airport system is being pulled apart," says Baer. "They're increasingly not running an airport system."
Airport operator BAA was forced to sell Gatwick in 2009, dropped its appeal to a forced divestiture of Stansted in August, and faces significant opposition to the expansion of Heathrow - which will be its last remaining London airport. The city's airports operate at or near full capacity, especially Heathrow.
"If they're going to continue as a world-class airport and a world- class city, you need world-class transportation facilities. They need the capacity," she continues. "My friends at Schiphol are quite liking this [expansion] decision because they have become the transfer point for northern England. [London is] losing all that economic benefit."