For many folks, Thanksgiving travel is a major headache. The Wednesday before Thanksgiving is always one of the busiest travel days of the year, with many airports experiencing twice their normal daily volume. This year, 2.42 million passengers are expected to fly next Wednesday, according to industry estimates. More passengers means long waits at check-in counters, bottlenecks at security checkpoints and the inevitable delayed flights.

Those kinds of headaches could soon become commonplace without serious infrastructure improvements at the nation's airports, warns a new study released this week from the U.S. Travel Association. It says that within 15 years, every other day will feel like the Wednesday before Thanksgiving at more than half of the country's largest airports. The figure is a troubling one, given the challenges already facing an air system where one in five flights is either delayed or cancelled.

But it's a problem that needs to be solved. Airport congestion and delays don't simply inconvenience passengers; they have the potential to affect the economy if they become so pervasive that flyers -- especially international visitors -- cut back on travel. The aviation system is responsible for around 5 percent of the country's GDP, according to a separate study published this week by the Eno Center for Transportation.

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The current problems -- from inadequate runways to crowded terminals to insufficient roadway and transit access -- vary from airport to airport. But they all require big money to fix. The Airports Council International-North America estimates a $57.9 billion backlog of projects that need to be completed at commercial airports by 2017. Meanwhile, a 2007 Federal Aviation Administration (FAA) study says 35 airports in 17 metro areas could reach capacity by 2025.

At John F. Kennedy airport in New York, for example, its four-way intersecting runway isn't adequate to meet demand, and its proximity to other airports causes congested airspace. Potentially, it could solve some of the problem by expanding beyond its existing boundaries, but that would cause political and funding obstacles. The airport in Newark, N.J., faces similar challenges. By 2024, unmet demand at just those two airports alone could result in $24 billion in lost spending, mostly from international travelers, according to the area's regional planning organization.

Making things worse? Airline consolidations and mergers over the past several years. Airlines now operate fewer hubs, entrenching the hub-and-spoke model that requires most travelers to change planes before reaching their destination. That's led to decreasing capacity needs at small and medium hub airports. But because the hubs are now more concentrated, delays trickle out to medium and small airports even when those facilities aren't congested. Case in point: Half of the 9 million passengers who fly through JFK continue on to another facility. Essentially, everyone has a stake in improving the conditions of the most congested airports, since they affect the whole network, the Eno Center argues.

Politically, though, the odds are against a solution. The Eno paper unambiguously concludes that the aviation network is unlikely to provide adequate capacity to meet its growth projections in the next 20 years because there are political impediments to increasing each of the main sources of revenue for airports.

Take, for example, passenger facility charges (PFC), which allow airports to charge up to $4.50 for each departing passenger (the fees are added when passengers buy their tickets). PFCs account for only 11 percent of revenue at big hub airports, but they are one of the only ways the facilities can raise their own funds. The cap has remained unchanged since 2000, resulting in decreased purchasing power, and many airport officials say they want Congress to allow them to charge more in order to fund improvements.

That's likely to be an uphill battle since the fee is levied on tickets and airlines don't want to see ticket prices go up. Although it wouldn't technically be a tax increase -- airports themselves would have to raise the PFC -- Congress would need to authorize them to do so, which it won't since it could be perceived as a tax hike, says Paul Lewis, an analyst at Eno.

Joel Bacon, vice president for legislative affairs at the American Association of Airport Executives, says airports see PFCs as a viable solution to capacity problems if only they had more flexibility. But airports -- typically units of local governments -- don't have the resources to fight airlines on the issue, which are adamantly opposed. "It's the reality of how they plan for things versus how we plan for things," Bacon says. "Nobody wants to support increased taxes and fees. It just gets caught up in the here and now." On the other hand, raising taxes on local residents to pay for work at a particular hub airport could be a tough sell, since those taxpayers would likely be skeptical of using their own money to improve part of a national network.

Another source of potential revenue could come from the federal Airport Improvement Program (AIP), which provides about $3.5 billion annually to airports for infrastructure improvements. The country's 382 "primary" airports are responsible for 99.75 percent of the commercial air passenger traffic in the U.S., yet they only get 65 percent of the program's funding. Instead, huge portions go to smaller airports used for business and general aviation that most members of the public never visit. That's due to a formula that ensures the money is distributed broadly rather than efficiently. Eno advocates for a more targeted approach, and airlines say they think AIP needs to be reformed too. But Lewis says that would be difficult: Politicians like the fact that everybody gets a piece of the funding. "I think Congress is pretty pleased with how it is," Lewis says.

Meanwhile, federal funds that pay for airport infrastructure are raised through a 7.5 percent tax on commercial airline tickets. But airlines have moved to a model that increasingly focuses on extra charges -- like baggage fees -- that generate billions of dollars that are immune from the tax. Airports could theoretically charge more for landing fees or terminal rental fees, but those are heavily regulated and would be opposed by the airline industry too. For airlines, boosting capacity at airports doesn't necessarily mean more profits, and while airlines wouldn't object to capacity improvements, "they have no incentive to make those investments," Eno writes.

Vaughn Jennings, a spokesman for the airline industry trade group Airlines for America said in an email that "necessary airport capacity infrastructure can be accomplished through existing funding sources." He said the airline industry has helped by developing mobile check-in apps and working with TSA on screening programs.

In 2015, the federal legislation that sets aviation policy and funding is set to expire, so stakeholders have ample time to prepare for the debate. For now, it's unclear which option -- if any option at all -- will be the best way to address the needs. Eno concludes, "Change will likely occur only when the larger business community comes together to call for substantive policy changes addressing how we operate and fund our aviation infrastructure."

And this Wednesday, the public may have the chance to see what it will look like if that doesn't happen.


Links to planning and infrastructure stories you might have missed

Cincinnati's mayor-elect says "the conversation about the streetcar is over" and pledges to work towards stopping $133 million project.

The Eno Center for Transportation proposes three ways to tweak Amtrak's reauthorization to improve passenger rail service.

New York's Metropolitan Transportation Authority dumps old subway cars into the ocean to create habitats for marine life. Fast Company shows off one photographer's eerie freeze frames of the cars as they enter the water.

A cyber attack on Israeli infrastructure shut down a roadway for eight hours, prompting major congestion, Haaretz reports.

One-way exit doors at the Syracuse airport could keep passengers from entering areas designated as exits only, but their design has critics calling them the "official arrival of the police state."

This month in Zurich, Starbucks launched its first store on a train. The store tells that they won't be lunching stores-on-rails in the U.S. any time soon, but they're testing the concept to see if it can be expanded beyond Switzerland.

Worsening congestion in and around Austin is causing Texas officials to consider the concept of a controversial toll "swap."

Pennsylvania is nearing passage of a plan that would raise fuel taxes and add $1.8 billion in annual transportation funding, the Harrisburg Patriot-News reports.