A few weeks ago a beleaguered passenger flying through Midway Airport gained viral fame by recording the line he was confronted with, which stretched almost all the way to the Orange Line, and nearly caused him to miss a flight he'd arrived two hours in advance for. He's not solely responsible for the attention given to long waits at TSA lines since, but there's been a flood of articles, growing in number as summer travel season approaches.

Crain's Micah Maidenberg, for instance, found that TSA staffing was down at both O'Hare and Midway. Here's the reason he was given:

Michael McCarthy, a spokesman for TSA, said in an email that the agency's budget, as allocated by Congress, is at its lowest level in five years.

That's due in part to how the agency said it wanted to staff security lanes at airports. TSA “anticipated a large number of passengers being eligible for expedited screening lanes, and therefore reduced the staffing requests to Congress,” according to McCarthy. “At the same time, airline passenger volume grew at unprecedented rates.”

That explanation has been reported elsewhere, such as by the Trib's Mary Wisniewski. But it's still more complicated. The problem, or at least one of many, goes back to last June, when the TSA abysmally failed internal tests given by the Department of Homeland Security; a couple months prior, a "sufficiently notorious convicted felon" was sent through expedited screening. These security failures cost the head of the TSA his job, led to more thorough and time-consuming screenings, and ended a program called "Managed Inclusion II."

Managed Inclusion II diverted some passengers into expedited screening lanes even if they hadn't signed up for one of the programs that allows you to use them, like the TSA's PreCheck program. Those diversions still happen, they've just been reduced in number.

So the TSA was using the expedited lanes to take pressure off the regular ones. Then they stopped doing that, but not enough people have gone through the process to get expedited, so the pressure built up again—made worse by tighter screenings in the regular lines, and by the assumption that more people would sign up for expedited lanes.

Specifically, 2.5 million people have signed up for PreCheck, and 7 million people are signed up for some kind of expedited program. (There are ones besides PreCheck, like the Customs and Border Protection programs Global Entry, SENTRI, NEXUS, which are more complicated and obscure.) TSA's new head, Peter Neffenger, wants to get that up to 25 million, and "to do so, enrollment needs to be above the daily pace of 10,000 signups for more than three and a half years." This,  Neffenger said, would "drastically change the way we can operate the system."

But how realistic is that? The PreCheck process is neither cheap nor easy. It costs $85 for five years. But that's not including the documentation. You can use a passport book or card (I don't have one) which is a minimum of $55, with a six-week wait unless you pay more to expedite it. (About a third of Americans have a passport.) You can use a birth certificate, but if you don't have one—I didn't until well into adulthood—that will generally cost money and take time as well. My home state of North Carolina charges a minimum of $24, and that has to be a money order, certified check, or business check, and the wait time is five to eight weeks, unless you pay to expedite it and/or for the ability to use a credit card.

If you've reached this point, congratulations, it's time to apply for PreCheck. You can either begin the application online and make an appointment for an interview—which could be a few days to a month—or do a walk-in visit a PreCheck location for an interview and fingerprinting. There are three in Chicago plus one in Crestwood, open during general business hours (a couple are closed around lunch), save for the one at Midway which is open until 7 PM on Mondays and Tuesdays.

(But if you don't live in a big city, your mileage may vary, quite literally. If you live in Champaign, the nearest TSA PreCheck is 70 miles away in Terre Haute, Indiana. The closest one to my hometown of Roanoke, Virginia, according to the TSA's portal, is 81 miles away in Greensboro, North Carolina.)

Once you get through that and put down your non-refundable deposit, it'll be a couple more days until you're cleared for PreCheck. At this point, you've spent $85 to $200, an hour or two to get to a PreCheck location and do the interview if you're lucky, and waited from a couple days to a couple months. It's not exactly Kafkaesque bureaucracy, but it's a non-trivial amount of time and money to save some time and irritation at the airport—which, until this year, there wasn't much of a difference.

Which gets to the heart of the matter: How big is the market for PreCheck?

A lot of people fly. Gallup's polling suggests that 45 percent of Americans fly at least once a year, 25 percent fly one to two times a year, nine percent three to four times, and 10 percent five or more times.

There were about 245 million adults in the U.S. as of 2014. (PreCheck eliminates people who have been convicted of, pled guilty or no contest to, or found not guilty by reason of insanity for a list of crimes, including some felony drug offenses, in the last seven years. It's not a big dent, but given that there were 1.5 million people in prison as of 2008, it's not trivial, either.)

If you assume that the market for PreCheck is people who fly five or more times a year, that's 24.5 million. So in order to reach TSA's goal, 100 percent of those people would have to sign up. If you expand the market to three trips per year and up, that's 46.6 million. More than half of them would have to sign up. If the market is everyone who flies at least once a year—at which point PreCheck is almost a push in terms of time cost for the majority of flyers—you'd still need about 23 percent market saturation. And that's not accounting for the fact that a quarter of flyers have never heard of it in the first place; the TSA only started really marketing the program last year.

So getting PreCheck status is sort of like going to the DMV… except more expensive… and if the majority of Americans only drove once a year… and you didn't actually have to go to the DMV to drive a car… and the DMV might be in another state. Building infrastructure is one thing, but you can't just hope that people will use it.

Surely more people will sign up for PreCheck as stories of three-hour waits at O'Hare continue, passengers sleep on cots in the terminal, thousands of people miss flights, and—perhaps more importantly—airlines continue to delay flights. Congress has expedited a bunch of money to pay overtime and train TSA agents, but reduced waits could also reduce demand for PreCheck, which requires a fair bit of demand to be desirable. Until then, travelers will have to weigh one frustration against another.