If it’s early December, it must be Buenos Aires.

Maybe Hong Kong? No, London! Wait – not far enough.

Sound absurd? Not if you’re a frequent flyer on the cusp of earning the next tier of elite status with your airline.

Most big airlines dole out their top-tier status levels by miles flown – or elite “qualifying miles” in frequent-flyer parlance. At most big airlines, flying 25,000 elite miles in a calendar year earns you the lowest-level of elite status (though most agree that’s not worth much these days).

Real road warriors can earn even higher levels of elite status if they clear 50,000 or 75,000 miles in a calendar year. Perks include things like free checked bags and priority check-in. Upgrades are complimentary on domestic flights – assuming you’re not outranked by other elites on your flight.

Hitting 100,000 elite miles earns you the highest published status for the frequent-flyer programs at big global airlines like American and United, while Delta requires 125,000. That’s when the biggest perks kick in, including a limited number of upgrades that can be used for lie-flat seats on long international routes.

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Alaska Airlines and Frontier Airlines have their own mileage-based elite levels. Even Southwest is in on the game; “A-List” status begins after 25 “qualifying” flights or 35,000 “tier-qualifying points” in a calendar year.

Regardless of the system, imagine rolling into the last month of the year just a few flights short of the next level of elite status. If you’ve flown 47,000 qualifying miles by Thanksgiving, you’re just 3,000 short of the next tier. Or maybe you’ve flown 95,000 miles, leaving you just 5,000 short of 100,000 – and the lucrative international upgrades that come with it.

That’s where the mileage run comes in. Many frequent flyers opt to take an extra trip, one that’s simply to earn the miles needed to upgrade to the next tier before the year ends and the mile-earning counter resets.

Late November through mid-December is a popular time for these runs. Not only is it the last window before the end of the year, but the period between Thanksgiving and Christmas is one of the slowest of the year – meaning bargains are more plentiful than usual. Conversely, cheap fares disappear on most routes around the Christmas rush.

New airline airfare spending requirements have complicated the status-oriented mileage run for some, but many still just need the elite miles. Plus, the fare from that last-minute trip also can help those also struggling to hit their needed “qualifying dollar” thresholds.

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My 2018 mileage run was a fairly aggressive one. I came into the Thanksgiving holiday with a count of 88,700 qualifying miles on American, the airline that has the most nonstop options from my preferred airport (Washington Reagan National).

To hit the next status level for American – “Executive Platinum” at 100,000 elite miles – I had to earn 11,300 elite qualifying miles (EQMS) by Dec. 31. Qualifying miles are still earned by distance flown, meaning I had to figure out a trip that was far enough but also inexpensive enough to be worth the effort. That, in a nutshell, is the art of figuring out a mileage run.

I weighed my options, but 11,300 EQMs is a complicated number to hit with a single trip. Berlin, London and Buenos Aires jumped to the top of my mind as options. So, I went to work crunching fares.

Berlin? No good. Fares on the dates I could travel were too high to be worth it.

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London? Too short – just 7,902 EQMs even with a connection at New York JFK. But international premium economy fares – which earn a 50 percent EQM bonus – had been on sale for just about $1,100 round trip. That upped the total to 11,854 EQMs. I thought I had my solution, until the cheap premium economy fares disappeared before I could book.

That left me with Buenos Aires, which at about $980 round trip seemed like the best option. But I had to plan carefully. Connecting through Miami didn’t earn enough EQMs – just 10,652 round trip compared to the 11,564 I’d get by connecting through New York JFK or 12,956 via Dallas/Fort Worth (DFW). Again, it’s the “art” of the mileage run.

Then, a wild card emerged. A friend was celebrating his birthday in Mexico City in early December and invited me to join. That sounded more appealing than a solo, three-day trip to Buenos Aires. But at just 4,254 EQMs round trip (via DFW), there’s no way that could work. Right?

Determined, I looked for a way to make it work. I had use-or-lose vacation days to burn by the end of 2018, so that expanded my options. “What if,” I thought to myself, “I combine Mexico City with some other place?”

I added San Diego to the mix, figuring I could visit good friends there as part of the journey. Still not enough; only about 7,204 miles, even with a six-flight itinerary. On a whim, I checked first-class fares, which earn double EQMs. Lo and behold, booking two of three one-way fares in first came out to be roughly the same price as the Buenos Aires itinerary.

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It provided enough EQMs – barely – at 11,462, though it required even more finesse. Connecting through Charlotte on the way to Mexico City didn't provide enough EQMs, so I went through DFW. It was a similar story on the return from San Diego, where only connections through Los Angeles, Philadelphia or New York JFK racked up enough miles (I opted for the latter).

With all the details in order, I booked the itinerary. It was six flights bought as three individual one-way tickets. In the end, I opted to pay extra for better flight times. I chose not to arrive at 10 p.m. or depart at 7 a.m. on any of my three legs so that I would have more time to visit (and more time to sleep).

My strategy likely wouldn’t sit well with some mileage-run purists. My 12 cents-per-EQM was certainly no great bargain. (Yes, hardcore mileage runners look at this metric!). But, conversely, I wasn’t flying only for the miles. I got to celebrate a friend’s birthday in Mexico City and see two of my closest friends (and their quickly growing 2-year-old daughter) in California.

These are trips I might’ve taken anyway, though probably not “combined.” Or at the last minute, right before Christmas. Some “purists” judge a mileage run simply by the cheapest way to achieve the objective. Some never leave the airport, flying an itinerary that gets them their miles without ever stopping along the way.

For me, I was happy to break the 100,000-EQM threshold by taking a few unused vacation days to see a few friends along the way. Now, my next choice will be to figure out where to try and use those international upgrades.

Stay tuned …

And now, your story...

Now it’s time for your stories. If you have taken or will take a mileage run this year, tell us your details. How far did you have to fly? How many EQDs did you have to earn? And, of course, where did you go and how did you pick it?

Share your details by leaving a comment, or tag me on Twitter @TodayintheSky along with the #mileagerun hashtag, and we'll compile some of the most interesting responses in a follow-up story. Tell us how many miles (or dollars) you needed and where you went to get them. And, of course, be sure to share any additional tidbits our fellow readers may be interested in.

We'll post a recap of the highlights after New Year's.