Their status is measured in precious metal…silver, gold, platinum…executive platinum or…United 1K?
"With heavy business travel I decided to concentrate all of my miles on one airline…and get the premier status and the perks that go with it," Zelle told CBS News correspondent Seth Doane.
Those perks include priority check in, bonus miles and free upgrades to first-class.
For road-weary frequent flyers, elite status - earned by collecting enough miles or flight segments - can make traveling much easier.
"I have nightmares about one of my flights being cancelled and being short a segment," said Zelle.
"A nightmare? Really," Doane asked skeptically.
"Oh, I do," Zelle insisted. "I lay awake at night going…now what days do I have open, where can I squeeze in one more flight if I have to?"
This fall though…her nightmare came true! Zelle, a Chicago lawyer, hadn't flown enough to renew her elite status on United…and that called for drastic measures.
"Today," Zelle announced, "we'll be going O'Hare to Des Moines, Des Moines to Denver, Denver to Des Moines to O'Hare."
Yup, a whole day of traveling… just to earn miles. It's called a "mileage run".
Zelle won't even leave the airports she visits. She won't see any of Denver or Des Moines and she doesn't mind that at all.
"Yeah, that's fine. It gets me home in time for dinner."
And that was only one of several mileage runs Zelle has made this year. Including one that took her from Chicago to San Diego to Los Angeles and back all in one day.
Doane also spoke to Randy Peterson who is something of a frequent flier guru who literally wrote the book - well, at least a popular magazine and website - about mileage runs.
"A mileage run is for a frequent flyer who doesn't quite make it at the end of the year", Peterson explained. "They might be a flight short or 3000 miles short and they're just so close and they say you know what, I don't have any more business travel the rest of the year, I'm going to go out and do a mileage run. So what they do is they simply go to the local airport and fly anywhere - they don't really care."
Peterson, the founder of flyertalk.com, estimates that every year hundreds of thousands of travelers make mileage runs.
Flyertalk is an interactive manual of mileage tips and has become its own community where posters help fellow travelers plan flight, find cheap fares and pick routes to gain the most miles.
As a result of frequent flier programs, airlines give away thousands of free flights and upgrades each year.
"There's always a cost when we do any kind of marketing program," said American Airlines' Billy Sanez, "especially the advantage program, but that's the cost of doing business."
Sanez is the director of communications for American Airlines, whose frequent flyer program is the oldest in the country with some 56 million members worldwide. Sanez is a former mileage runner himself.
"When American Airlines started the phenomena of frequent flyer miles programs I don't think that we envisioned having such loyal fans," said Sanez, "but it's great to have such loyalty from our customers that come and fly and fly so much with us."
Michael Feder is one of those loyal American flyers. Feder has been voluntarily sleeping away from home…just to retain his status.
"My assistant in Chicago helped me find inexpensive flights," he explained, "that were short and that we could hop on, go down, either stay the night or turn right around and come back. So I've got six different trips I've got to take just to stay executive platinum."
"And what have these trips been?" Doane asked him.
"They have been…insane!"
Feder didn't know that what he was doing was called a "mileage run", and seemed somewhat reluctant to even talk about it.
"What does your wife think?" Doane asked.
"Ah, she's benefited from a few upgrades over the last coupled of years," Feder told him, "so she sort of gets it, she knows I'm crazy, but she gets it, she understands."
Crazy to some is prudent to others says Flyertalk's Peterson.
"It's no different than in any other things, whether you're a coupon clipper for savings at the supermarket or trying to do different things in other industries out there. But the idea, given that air travel is the way it is today, there is one thing that you can do well for yourself, and that is become an elite member."
And talk about miles isn't limited to airports. Doane checked out a mileage "do" in New York City. These are get togethers that attract people from around the country who fly in, meet up and well…talk about miles!
The one Doane paid a visit to at La Bonne Soupe, a restaurant in New York, pulled in travelers as far as South Carolina and Vegas. Mark Blanchard organized the event.
"Isn't this more than just travel?" Doane asked him, "I mean, there's an intricate knowledge of the insides of the airline industry."
"Exactly," Blanchard agreed. "These people read. They study. They try to learn all the little tricks and ways, 'How can we get the most value out of our money'."
And that makes these folks de facto professors of the skies.
Jay Teadtke told Doane that he has to "dumb it down" when he talks to other people about travel.
"I just, you know, if I'm talking about airports, I say the name of the airport rather than just spout out the three-letter code," Teaktke explained.
Meanwhile, on her layover at D-E-N, before heading back to O-R-D, her stopover in D-S-M having been canceled, Jenny Zelle took a break from travel at United's "Red Carpet Club".
"Is this really fun?" Doane asked her.
"It is fun!" she answered. "That's the thing, you have to go into it with the right frame of mind. You have to expect that things are going to happen, it's just the nature of the beast. Things will go wrong. I still think it's relaxing. Hey, now I'm flying home on a triple-7. It's a great plane. I have two books with me."
With airports packed with holiday travelers, many of us would stay far away in December. But it is the one of the busiest months for mileage runners, the last month to ensure status for the following year.
So while millions of people are desperately trying to get somewhere, thousands more are desperate to go, well, nowhere.