Project Sign
Project Sign (1948) was the U.S. Air Force’s earliest formal UFO-study effort, predecessor to project-grudge (which in turn preceded project-blue-book).
PURSUE Release 04 (July 10, 2026)
The Hill’s coverage of PURSUE Release 04 surfaced a 1948 Project Sign document compiling 100 sighting reports from 1947–48, explicitly tying the wartime increase in sightings to WWII “foo fighter” reports and the 1947 roswell-incident. This fills a gap in the vault’s Sign → Grudge → Blue Book institutional lineage.