Soviet Union

A former transcontinental state spanning Eurasia, the Soviet Union was the primary geopolitical rival of the United States during the Cold War. US intelligence agencies closely monitored Soviet airspace for both advanced aerospace technology and UFO sightings to determine if UAPs were of Soviet origin. Declassified documents often reveal a mutual, albeit secretive, interest in UAP phenomena by both superpowers.

The primary Cold War adversary of the US, whose airspace and potential aerospace breakthroughs were heavily monitored in early UAP intelligence assessments.