The U.S. Air Force investigated more than 250 UFO cases between 1947 and 1949 under Project Sign.

Authors

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

Sources

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

Referenced by nodes (4)

• Air Force entity
• Project Sign concept
• UFO incidents concept
• Project Sign event