DOW-UAP-D097, Project Sign Progress Report, 1948

The progress report counted 31 descriptions using oval, disc, or saucer shapes and 11 reports with associated sound.

The object was described as being oval, disc or saucer-shaped 31 times

It recorded claimed high rates of climb and apparent hovering, while noting that reported size estimates varied enormously.

High rate of climb, as well as the apparent ability to remain motionless or hover

The tabulation listed 77 single-object sightings, 21 involving two to five objects, eight involving five to ten, and nine involving more than ten.

Number of objects per sighting

Exhaust trails were reported 23 times, and estimated speeds ranged from very slow or hovering to supersonic; these were compiled witness estimates.

Exhaust trails were reported 23 times

The incident review labeled one photograph and associated story a hoax undertaken for publicity and money.

both the photograph and story were a hoax, perpetrated for publicity and money

Reviewers of the Rhoades photographs concluded the image was photographic rather than a film-development defect and described shutter-related trailing, but did not identify the depicted object.

the image is of true photographic nature

An attached Aeroplane article surveyed the history of low-aspect-ratio aircraft instead of treating saucer-like appearance as evidence of an unknown technology.

The Story of Low Aspect Ratio Aircraft

The technical appendix discussed Canova disc-wing wind-tunnel tests and flight attempts, documenting historical engineering work on circular aircraft configurations.

wind-tunnel tests were made in Turin and at Rome of five Canova projects

The article argued that no known aircraft combined very high and fast flight with hovering and near-vertical ascent or descent, framing those reported capabilities as an aerodynamic problem rather than a verified performance record.

No other aircraft is known to do that