Why Do Planes Fly Over Alaska Instead of Straight Across the Pacific?

Added: 2026-05-11

[00:00:02][music] >> You are watching the live flight map on the screen in front of your seat or on your phone before boarding. Your flight is going from Los Angeles to Tokyo. The Pacific Ocean is right there on the screen, enormous [music] and flat, an obvious straight line between the two cities. But the route does not go straight across. [music] It bends upward, over Alaska, over the Aleutian Islands, through [music] airspace that looks nothing like a direct path.

[00:00:34]Your first thought might be safety, avoiding open water, staying near emergency airports. And that is not entirely wrong, but it is not the main reason. The real reason the route looks like a detour is that the map itself [music] is misleading you. What appears to be the long way around is, on an actual round planet, often the shortest distance between the two cities. Let's get into it right here on Secrets of Simple Things.

[00:01:09]The shortest path is curved.

[00:01:12]At its core, the question is about the difference between a flat surface and a curved one. On a flat map, the shortest path between two points is a straight horizontal line. But the Earth is a sphere, and on a sphere, the shortest path between two points is not a straight line on a map. It is a curve that arcs toward the nearest pole.

[00:01:34]Picture a globe in front of you. Take a piece of string, press one end against Los Angeles, and pull the other end taut to Tokyo. The string does not run parallel to the equator. It lifts northward toward Alaska. That arc is the shortest distance between those two cities on a round planet. The flat map just makes it look wrong.

[00:01:57]Maps made this confusing.

[00:02:00]It did not start with a misunderstanding of aviation. It started with a map drawn in 1569.

[00:02:07]Navigators and mathematicians had understood the geometry of a round Earth long before powered flight. Ancient Greek scholars had already established that the Earth was spherical and had worked out the mathematics of great circles, the shortest paths across a curved surface. Medieval Arab navigators refined these calculations further. The idea that the shortest route between two distant points on Earth curves toward the poles was not a discovery of the jet age. It was classical geometry. The confusion came from cartography. In 1569, the Flemish geographer Gerardus Mercator created the map projection that still shapes how most people visualize the world. The Mercator projection solves a specific nautical problem brilliantly. If you draw a straight line on a Mercator map, it represents a constant compass bearing. For a sailor crossing the Atlantic who needed to hold a steady heading, this was extraordinarily useful. You could draw your course on the map with a ruler and follow it with a compass. But, the Mercator projection achieves this by stretching the world. The closer you get to the poles, the more distorted the map becomes. Greenland appears roughly the same size as Africa on a Mercator map.

[00:03:19]In reality, Africa is about 14 times larger. Straight horizontal lines near the top of the map look like manageable routes. Curved lines that dip toward the poles look dramatically longer than they actually are. The map was never designed to show which path between two cities was shorter. It was designed to make straight compass lines possible at sea.

[00:03:42]But, this is the map most of us have grown up with, the one on classroom walls, the one in atlases, the one underlying most digital mapping tools.

[00:03:51]And it shapes our intuitions about global distance in ways that are often quietly wrong. When long-haul commercial aviation began expanding dramatically after World War II, route planning teams quickly discovered that the routes that looked shortest on standard maps were not the routes that actually covered the least distance on the planet's surface.

[00:04:12]Flying the real shortest path, the great circle route, saved fuel and time on every long-haul crossing. The map that most people used to imagine the world was not the map that pilots used to fly across it. That gap between the map we see and the world we are actually flying over is still there today.

[00:04:34]What actually happens up there?

[00:04:37]So, what is actually happening when a flight from Los Angeles to Tokyo curves north over Alaska? The aircraft is following the great circle route between the two cities. A great circle is any circle drawn on the surface of a sphere whose center is the center of the sphere itself. The equator is a great circle.

[00:04:54]Any line of longitude is a great circle.

[00:04:57]And the shortest path between any two points on a sphere always lies on a great circle. The great circle between Los Angeles and Tokyo passes over the northern Pacific and clips the edge of Alaska. It is shorter than the horizontal path across the middle of the Pacific because it is traveling along the actual surface of a round planet, not across the imaginary flat version that the map draws. Think of it this way. If you cut an orange in half and placed one dot on the left side of the cut surface and another on the right, the shortest path across the surface of that orange would arc over the top of the curve, not run straight across the flat middle. The same principle operates at the scale of the Earth. The great circle is the foundation, but airlines do not fly it in isolation. Jet streams also shape the route. These are powerful rivers of fast-moving air that circulate at high altitude. The polar jet stream flows roughly east to west across the northern hemisphere at speeds that can reach well over 150 km/h.

[00:05:58]A flight traveling westward from North America to Asia can sometimes ride a tailwind in this stream, reducing flight time and fuel consumption significantly.

[00:06:08]A flight traveling eastward may route slightly south to avoid flying into the same headwind. Emergency diversion options also factor in. The Alaskan coastline offers airports that would be unavailable over the open Pacific, which provides options in the rare event that a diversion becomes necessary. But the jet streams and emergency logistics are adjustments to the route. The great circle is the reason the route goes north in the first place. Remove the great circle logic and none of the other factors would place the aircraft over Alaska at all.

[00:06:43]The map is the problem. The assumption almost everyone starts with is that the route curving north is a detour, that the direct path goes straight across the Pacific and the Alaska curve is something added on top of it for some secondary reason. That assumption has the logic exactly backwards. The route that curves over Alaska is the direct path. The horizontal line across the middle of the Pacific that looks so clean and obvious on the flat map is not the shorter route. It only appears shorter because the Mercator projection inflates the scale of high latitude areas, making a northward curve look dramatic and extended when it is in fact more compact on the surface of the actual planet.

[00:07:26]The plane is not going around something.

[00:07:29]It is going across something, around Earth, in the most direct way available.

[00:07:34]The map is the thing that makes this look wrong. This matters beyond aviation. The same distortion applies to how we imagine distances between any two places at high latitudes. How far Canada is from Russia, how large the Arctic is relative to the tropics, how far Northern Europe is from Japan. Our intuitions about global geography are shaped significantly by a map that was designed to help sailors hold a compass bearing at sea in the 16th century, and that has never been particularly well suited to answering questions about distance or scale. The map shapes how we see the world, and sometimes the map is quietly misleading us.

[00:08:17]Every flight uses this.

[00:08:19]Today, you will find the great circle principle running silently inside every commercial flight routing system on the planet. Airline dispatch software calculates the great circle distance as its starting point for every route. From there, it adjusts for jet stream position, restricted airspace, weather systems, and fuel load. But, the great circle is always the baseline. It is the floor beneath every flight plan. The economics matter enormously. Jet fuel is one of the largest operating costs for any airline, sometimes accounting for a quarter or more of total expenses. Every kilometer of unnecessary distance flown translates directly into wasted fuel and added cost. Flying the actual shortest path, even when it looks strange on a screen, saves money on every single long-haul flight. The same principle that sends Los Angeles to Tokyo flights over Alaska also sends New York to London flights arcing northward over the North Atlantic rather than following a straight horizontal line.

[00:09:20]Flights from the US West Coast to Australia dip south for the same reason, following the curve of the sphere in the other direction. Every long-haul route on the planet is a version of this same geometry. The round Earth has shorter paths than the flat map suggests, and every flight you have ever taken on a long international crossing has has been navigating that difference. The seatback map that shows your plane curving across the screen is showing you real-time great circle navigation. The route looks odd. The route is optimal.

[00:09:54]When straight looks curved.

[00:09:56]So, why do planes fly over Alaska instead of straight across the Pacific?

[00:10:01]Because on a round planet, the Alaska route is the straight one. The flat map is showing you the shortest path and making it look like the longest one. A flight path that appears to be a detour on a flat screen may be the most direct route on the actual surface of the earth. Sometimes the plane is not taking the long way. The map is simply drawing the shortest path in a way that our flat map intuitions read as curved. What we see on a screen shapes what we expect from a three-dimensional world, and sometimes the most direct path does not look direct at all until you change the surface you are looking at it on. If this made you look at a flight map differently, let us know in the comments what everyday detail you want us to explore next. We might make it our next episode. Thanks for watching. History often hides in the smallest details.