The United States Air Force's Project Sign was created at the end of 1947 and was one of the earliest government studies to reach a secret extraterrestrial conclusion.

Authors

• Person: Not available Organization: Wikipedia
  Unidentified flying object - Wikipedia

Sources

• Unidentified flying object - Wikipedia en.wikipedia.org Wikipedia via serper

Referenced by nodes (2)

• United States Department of the Air Force entity
• Project Sign concept