Project Sign's first report, and the study the Air Force revised twice

The U.S. Air Force's institutional history with 'flying saucers' begins with Project Sign, established at Air Materiel Command in 1948 as the service's first formal effort to collect and evaluate the reports — the project that would later become Project Grudge, and then Project Blue Book. PURSUE Release 04 publishes DOW-UAP-D097, Project Sign's initial progress report, detailing 100 sightings from 1947 and 1948 — bound together, oddly, with a clipping from the British aviation magazine The Aeroplane titled 'The Biology of the Flying Saucer,' a reminder of how quickly the subject crossed from military report into popular press.

Alongside it, Release 04 publishes both surviving drafts of Air Intelligence Division Study No. 203, 'Analysis of Flying Object Incidents in the United States' — the December 10, 1948 draft (DOW-UAP-D093) and the April 28, 1949 revision (DOW-UAP-D094), which AARO's own accompanying notes describe as substantively similar to the first. Both drafts reach the same uncomfortable conclusion, stated almost identically in each: 'it appears that some object has been seen; however, the identification of that object cannot be readily accomplished.' Unable to close the question, the study offers two 'reasonable' categories of origin — domestic or foreign technology — and argues that if the answer is foreign, the prudent working assumption is Soviet.

Two further files trace the same institutional thread into the mid-1950s. DOW-UAP-D095 covers joint U.S.-Canadian assessments of the Avro 'Project Y2' near-circular VTOL aircraft — the same saucer-shaped aircraft program referenced in Release 04's Senator Russell file — including a 1954 warning that Project Y2's own circular airframe could be mistaken for a UFO by an unfamiliar observer, plus a separate, unrelated July 1955 incident near Newfoundland in which a review committee was 'unable to explain' a USAF KC-97's simultaneous ground-radar returns and aircrew visual sighting. DOW-UAP-D096 collects 1955 correspondence between government departments, Congress, and private citizens about sightings and about what Project Blue Book — Sign's eventual successor — was finding.

The last file closes the loop institutionally. DOW-UAP-D092 is the U.S. Air Force Scientific Advisory Board's 1966-67 ad hoc committee review of Project Blue Book, which recommended the Air Force contract a university-affiliated scientific team to review selected cases. The Air Force adopted that recommendation; it produced the Condon Committee, and the Condon Committee's conclusions led directly to Project Blue Book's closure in 1969 — the end point of a line that started with Project Sign's first progress report twenty-one years earlier.

Read as a set, the six files are close to a complete paper trail of the U.S. Air Force's twenty-year public posture on the subject: an opening report that couldn't reach a conclusion, a study revised once without changing its mind, a live saucer-building program checked against the reports it might explain, and the internal review that eventually recommended shutting the program down. PURSUE Release 04 is the first time all six have been published together.