In the event World War III broke out between the Soviet Union and the North Atlantic Treaty Organization, Sweden intended to remain neutral.
After all, they’d managed to sit out World Wars I and II.
But there’s also a growing recognition that their neutrality would not be respected. A 2015 New York Times report noted that a Russian submarine sank in Swedish waters in 1916 after colliding with a Swedish vessel. In the 1980s, there were also a number of incidents, the most notorious being “Whiskey on the Rocks.” According to WarHistoryOnline.com, a Soviet Whiskey-class diesel-electric submarine ran aground off the Swedish coast in 1981, prompting a standoff between Swedish and Soviet forces that included scrambling fighters armed with anti-ship missiles.
The Soviets knew Sweden could threaten their northern flank, and the Swedes knew that they may well have to fight the Soviet Union, even though they were neutral. Should a NATO-Warsaw Pact war break out, the Swedes made contingency plans to be able to deploy their Air Force, and keep fighting in the event the Soviets attacked.
Swedish fighters serving with the Flygvapnet (Swedish air force) in that timeframe were the Saab J 35 Draken and the JA 37 Viggen. The Swedes did draw lessons from how the Israeli Defense Force hit Egypt, Syria, and Jordan in the opening hours of the Six Day War, and developed a way to make sure that the Soviets (or anyone else) would not be able to carry out a similar strike.
The new approach was called “Airbase System 90” or “Bas 90” and featured not only dispersal of the aircraft, but the widening of roads to allow them to be used as runways.
Below is a video produced by the Flygvapnet discussing the new system. While the audio is in Swedish, it has English captions.