ABOARD AMERICAN AIRLINES FLIGHT 9454 » Eric Mueller’s vacation started when his plane filled with smoke. Soon, people slid down an emergency chute, inflated life vests and climbed into a raft.

Mueller loved every minute of it.

Most days he runs a book review website. But on this day he was living out a fantasy at American Airlines’ flight attendant academy, practicing evacuation procedures most people hope to never use.

"I look at the safety card. It’s not supposed to be a comic book of things you want to try, but it all just looks cool," said Mueller, 40, of Los Angeles.

There are people who grew up wanting to be Mickey Mantle. They go to Yankees fantasy camp. Others dream of playing Carnegie Hall. They join the summer orchestra. Then there are aviation geeks like Mueller. People like him — and there are more than you think — charter a commercial airliner and hop across the country visiting the meccas of the aviation world.

The most recent journey had 160 people paying up to $1,699 for a seat and access to spots normally off limits: Boeing’s sprawling 737 factory, American’s mission control-like operations center and the cockpit of the world’s largest passenger jet.

Tickets sold out in 17 minutes.

"This is sort of the ultimate airplane nerd event," Mueller said.

Most people board a plane to escape to a tropical beach, see the Eiffel Tower or visit their family. For this group, the journey isn’t just half the fun. It’s the whole point.

They can differentiate between Boeing and Airbus jets just by looking at their tails. They know that on even-numbered flights, meals are served first from the front left of the cabin, while on odd-numbered flights, it’s the back right.

"Usually in your life, you’re the only one who knows this stuff," said Gabriel Leigh, 28, a filmmaker and writer from Hong Kong.

The camaraderie was part of the trip’s appeal. Sure, it was really cool to walk inside the first 747 ever built. But it was also fun to gulp down gin and tonics midair with other guys — 3 out of 4 passengers were male — who have the same passion for flying. How much fun? Well, American stocked the plane with four times the liquor of a normal flight.

In each row, stories were swapped of amazing meals and opulent hotels in faraway lands — all paid for with frequent flier miles. These travelers don’t just love to fly; they are obsessed with collecting frequent flier miles at the cheapest possible cost.

The fliers, who ranged in age from 20 to 81 and hailed from as far away as Chile, India and Italy, know the ins and outs of the programs better than anybody else and share pointers in online travel forums such as MilePoint. One tip: Prevent miles from expiring with a tiny online purchase at Target, Macy’s, iTunes or another retailer that’s part of the airline’s shopping portal.

Such expertise led American Airlines and several other travel companies to help set up the trip and use it to pick the brains of these veteran fliers. They wanted to know what these travelers like and hate about the loyalty programs. Airlines need to keep their most frequent customers happy. The top 20 percent of American’s customers generate about 70 percent of its revenue.

That’s why Suzanne Rubin, new president of American’s frequent flier program — AAdvantage — hopped on the plane, along with other executives, for what she called a "crash course in customer research."

For those who don’t travel frequently or play the mileage game, it can be daunting to understand the appeal of the programs. It’s not just about free trips. It’s a hobby — some would say obsession — similar to collecting stamps or brewing your own beer.

"Everybody has an interest. My neighbor polishes his 1967 Cadillac every other day," said Tommy Danielson, 40, director of sales at a telecommunications company. The Chicago resident organized the trip, called a MegaDo — frequent flier lingo for a large group of people meeting up to talk miles. It was the fourth such adventure Danielson has put together since 2009.

Along the way there was plenty of bragging about mileage runs — cheap flights taken only to accumulate enough miles to qualify for elite status.

Michael Rubiano, a Silicon Valley product manager, did six such round trips to Chicago over eight days last month. He would catch a flight after work, sleep on the way to Chicago, immediately turn around and sleep on the flight home. Rubiano, 41, then showered in the San Francisco lounge, changed clothes and went to work only to repeat the trip eight hours later.

Each of his six tickets cost him less than $200 and, thanks to some bonus offers, earned him 11,076 miles on American to be used later for a dream vacation. All told, that gave him 66,456 miles and put him over the top in his annual quest to re-qualify for the airline’s top elite status.

With that status he gets another year of upgrades, free liquor, waived bag frees, the ability to skip security lines and double miles on all his flights. Compare that with the folks in the back who get … well, there’s a reason some in the industry refer to coach passengers as "self-loading freight."

A free domestic coach ticket can be had for 25,000 miles. But that’s not the goal. People in this group would rather shell out the $300 for the ticket and save for a big reward like flying first class to Asia for 125,000 miles, a ticket that normally sells for more than $10,000.

Once you start gaming the system, the miles rack up fast. Those on the MegaDo trip have a lifetime average of 1.6 million miles — earned through flying and credit cards — with American alone.

The man with the most: Michael Joyce, 61, from Forest Park, Ill. His lifetime total is more than 44.4 million. (The top AAdvantage member has 77.6 million miles but wasn’t on this trip. Accumulating millions of miles involves not just frequent flights, but also bonuses and miles received through credit card purchases.) For eight years Joyce, a former computer systems analyst, commuted between New York and Chicago. In 1994 he bought a lifetime unlimited-travel pass for $500,000 and now hops around the world for fun.

Less than a third of the miles he generates are actually flown. The rest come from various bonuses. Joyce donates miles to his church and gives flights to friends who can’t afford vacations. He also bid 453,000 miles to secure a seat on the MegaDo.

(The MegaDo also raised more than $65,000 for charity, auctioning off items like a Qantas deck of cards, British Airways pajamas, model airplanes, fluorescent yellow rain suits worn by American’s ground crew, two free tickets to Europe and 60,000 American miles.)

As with every good vacation, there was a chance to get souvenirs.

There was a stop at the Boeing store in Seattle — yes, there’s really a Boeing gift shop. It’s just south of downtown, steps away from the runway at Boeing Field. The group rushed in and stocked up on yellow 787 ties, aviator teddy bears, Boeing Christmas ornaments, garment belts fashioned out of airplane seat belts and T-shirts saying, "If it’s not Boeing, I’m not going."

But the real mementos were the photos. Most tourists snap shots in front of the pyramids, Machu Picchu or the Taj Mahal. At Los Angeles International Airport, this group pressed up against a chain-link fence to take photos of a Cathay Pacific 777 nose to nose with a Qantas A380. There was something sexy about the way the two giant planes faced each other.

Once onboard, like kids set free on a playground, the passengers climbed into the cockpit, spread out in plush first-class beds and crawled into the hidden bunk beds where crews nap during long trans-Pacific flights. Moments later, photos were on Facebook.

But what else would you expect from folks who, during a tour of an elite check-in area, were excited to play airline ticket agent?

"If I could strap wings to my back, I would," said Harry Livingston, 56, a former Navy flight surgeon, recreational pilot and emergency room doctor from New Rochelle, N.Y.

Even the most mundane parts of flying excited this group. American chose to premier its new safety video on the flight. There were wild cheers and screams as it ran. People recorded it with their iPhones and chanted "play it again" when it finished.

It turned out that one flight attendant working the trip was also featured in the video. She was treated like a movie star. When the video was over, the passengers did what star-struck fans do: They asked for her autograph — on seat-back safety cards.

Then they fastened their seat belts, returned tray tables and seat backs to the upright and locked position, and prepared to take off … yet again.