Fighter jet engines roared this week on a stretch of highway in central Finland where the military was training on stretches of road that double as backup runways.

One of dozens of Finnish reserve runways, the empty highway near the town of Joutsa was the scene of an annual Air Force exercise with F/A-18 Hornets taking off and landing.

The maneuvers come amid heightened geopolitical tensions due to the war in Ukraine and as Finland moves towards joining NATO.

“The exercise went well. The goals were met ahead of schedule,” Vesa Mantyla, the officer in charge of the exercise, told AFP.

As of Monday, the drill closed a section of Finland’s main road connecting Helsinki to the north of the country.

The aim of the exercise was to train a new group of Nordic country fighter pilots to take off and land on these rural runways.

With over 70 percent of Finland’s forest area, the highest percentage in Europe, it has adapted its military to take advantage of its geography.

In times of war, part of the Nordic country’s fighter jet fleet would operate from these forest-covered ad hoc bases.

“As we have seen in Ukraine, ballistic and cruise missiles are often used on fixed targets,” Mantyla explained, citing his country’s long shared border of about 2,000 kilometers (1,250 miles) with Russia.