Finding a "perfect" connection point

There are lots of ways to look at air traffic data. Sometimes it is pretty videos showing flight patterns. Or trends over time. Or airline route maps. But a recent thread on FlyerTalk got me thinking about “perfect” connections. In this context I’m thinking of perfect as a city pair where the distance between the airports can be matched by a pair of connecting flights, still starting and finishing in the same place but with a stop along the way and no extra miles flown.

South African Airways used to fly between Johannesburg and JFK Airport in New York City via Dakar, for example. In that case JFK to Jo’burg is only 3 miles shorter than the nonstop. Close, but not quite perfect. St. Louis to Toronto via Detroit is the same distance as the nonstop.

DTW happens to sit exactly on the route between St. Louis and Toronto
Map generated by the Great Circle Mapper - copyright © Karl L. Swartz.

So that’s one “perfect” route, but how many others are there? Way more than I expected.

For a different project a while back I collected data on routes flown. I ended up with roughly 22,000 city pairs. That’s not the full world of flight paths, but it is enough to start playing with the details and get some interesting results.

Setting the threshold at <25 miles deviation for the connection point I came back with 6,816 routes that fit that pattern; nearly 800 are truly perfect with a zero mile deviation.

Not all are unique. There are many cases where a city pair can have multiple en route connection points that are “perfect” or darn close. Stockholm to Palma de Mallorca has one perfect connection point – Frankfurt – and three other options (Zurich, Geneva, Copenhagen) within 5 miles of perfect.

So many perfect or near-perfect routes between Stockholm and Palma de Mallorca
Map generated by the Great Circle Mapper - copyright © Karl L. Swartz.

Between Atlanta and Istanbul there are seven connection points (BOS, BRU, DUB, DUS, IAD, FRA, JFK) that are within 2 miles of perfect.

So many perfect routes!
Map generated by the Great Circle Mapper - copyright © Karl L. Swartz.

Perfectly perfect??

Taking the idea of perfection another step further I started to look at options where the connection point was exactly half way between the other two cities. Surely that would be perfectly perfect, right? Alas, it was not to be, though there are a couple options that are pretty darn close. Half way between Dulles (IAD) and Houston (IAH) sits Huntsville, Alabama (HSV). Well, almost half way. The Dulles segment comes in at miles 596 compared to 594 for the Houston segment. Ottawa (YOW) is 3 miles closer to Quebec City (YQB) than to Toronto Pearson (YYZ).

A couple routes that are nearly perfectly perfect
Map generated by the Great Circle Mapper - copyright © Karl L. Swartz.

In Europe there are a couple similar routes, also within a mile or two of perfectly perfect.

More almost perfectly perfect routes
Map generated by the Great Circle Mapper - copyright © Karl L. Swartz.

One of the longest perfect routes I can find is Doha (DOH) to Miami (MIA) with a pair of connections that don’t materially add to the total miles flown. Milan and Paris sit right along that flight path.

A very long perfect connection path
Map generated by the Great Circle Mapper - copyright © Karl L. Swartz.

Of course, there’s the part where even a perfectly situated connection still means at least two extra hours of travel time with the slower speeds at lower altitudes and the connection window. That’s part of why the ultra long-haul routes can still attract lots of passengers. But sussing these out of the data set sure was fun for a Sunday morning.

Oh, and about the pretty video thing I mentioned in the lede:

For those who want to see more details, here’s the data I was working with. Yes, I know some of it is bad. My source isn’t perfect and I don’t have the code to repair it readily available right now. But it is mostly accurate and I double-checked the stuff I reported above.

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Seth Miller

I'm Seth, also known as the Wandering Aramean. I was bit by the travel bug 30 years ago and there's no sign of a cure. I fly ~200,000 miles annually; these are my stories. You can connect with me on Twitter, Facebook, and LinkedIn.


  1. how much does the connection save the traveler? for STL-YYZ on random dates, $209, $140, & 173 v $219. Only July 28, the DTW connection is more expensive than the non-stop. I suppose with a large enough data set you could some general numbers.

    1. Depends wildly on the city pair and other factors. In some cases the “perfect” connection would be a mixed carrier itinerary that would blow up pricing.

      This was more about realizing how many airports are in good connection locations for typical great circle routes. DUB shows up in the list as a mid-point a lot, for example.

  2. One I had noticed with the introduction of DTW-GRU is that NRT-DTW-GRU clocks in at 9986, where NRT-GRU is 9984. Two miles off for a distance of almost 10K miles is pretty amazing, especially as this is probably one of the best connections available between those pairs.

  3. We got very close last year with DCA-DTW-ICN – fewer than 100 miles longer than IAD-ICN nonstop. It was going to be an award ticket either way, and given that the connection was in business and the nonstop was economy, those extra 80 or so miles plus a bit of ground time weren’t a bad trade-off.

  4. How’s this one for perfection? This was my most common work commute in 2016 and 2017. Of course, I had to fly it with the connection – it doesn’t exist as a nonstop on any airline.

  5. In other words, connections to avoid. If I’m going to go through the hassle of connecting, I darn well better be earning extra miles! 😉

  6. Interesting that you chose ARN-PMI as an example with FRA as a stopover. I flew ARN-PMI last year and the route took us west over Denmark, then south over Hamburg and Luxembourg, then over the south of France and into Palma. Got me wondering if a 1-stop via FRA might actually be shorter in real life?

    1. Planes almost never fly a truly “direct” route so it is all academic anyways. Winds, politics and other factors all come into play.

  7. Very interesting but I put the more weight on the properties of the connecting airport.

    1. Decent IROPS possibilities? ORD is better than MKE in this regard.
    2. Red eye considerations. For example, if flying from PDX to Europe, a connection in SEA or SFO may allow more sleep than JFK or BOS.
    3. Weather. An ORD connection is riskier in the winter than DFW or DEN.

  8. MFR-ATL is 2,163 miles. Fly United and connect in DEN and it comes to exactly 2,163. Fly Delta and connect in SLC and it’s a whopping 2,164 miles. So the two places you would most likely connect on that trip are perfect and 1 mile off perfect.

  9. How good are the lounges?
    How delay prone? Weather and ATC
    Save money?
    Way more important than whether it is on the great circle

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