Ask the pilot: Why do same flights take different routes?

How do planes actually fly, what exactly is turbulence and why are airplane windows always round? The best people to answer your questions about the wonders of aviation are SAS pilots.

When watching Flightradar24, I’ve seen that flights between the same destinations often use very different routes. Flights from Tokyo to London sometimes pass over northern Norway and sometimes pass over southern Finland. Sometimes the flights from Oslo to Tromsø only fly over Norway, and sometimes they fly over Sweden as well. 

Which factors determine which routes will be used?


Hello Hugo,

Troy Nøstdal

Age: 27
Career: Troy first started his career with aircraft cleaning and catering, before his three-year pilot education in Tromsø. He flew Boeing 737 for almost two years prior to joining SAS as a First Officer in 2014.
Home base: OSL
Flies: Boeing 737
Flight hours: 3.300

Read more

Thank you for your question. In general, we choose the route between A to B that takes the shortest time. There are however a few factors that affect our routing.

For a start, pre-described routes make up the airspace. These are "highways" that we follow called airways. These airways take us in the general direction we would like to travel and are used by air traffic control to separate other aircraft travelling in the same direction. Sometimes, when the air traffic controllers see that there is enough space between us, we are given a shortcut that takes us off that route.

We also plan our routes in relation to how the wind is blowing and if there is bad weather forecast on the way.

There are also costs for flying over different countries. That is why the preferred route between Oslo to Tromsø is the one that only passes over Norway, even though the route that passes over a small portion of Sweden is actually quicker.

I hope this answers your question.

First officer Troy Nøstdal

Did you find this article inspiring?

Give it a thumbs up!


Book trip


Close map


From the article

Share this tips


Looking for something special?

Filter your search by