Project Blue Book Case #1236. On May 29, 1952, observers in San Antonio, Texas, witnessed a high-speed unidentified object transiting the sky over the city. The object appeared disc-shaped or oval, with a metallic sheen visible in the afternoon sunlight, and moved at a velocity that witnesses described as far exceeding any aircraft they had seen.
San Antonio was — and remains — a major hub of U.S. military aviation. Home to Lackland, Kelly, Randolph, and Brooks Air Force Bases, the city's skies were among the most heavily trafficked military airspaces in the country. Witnesses in this environment were accustomed to observing all manner of military aircraft, from propeller-driven trainers to the latest jet fighters, making their insistence that this object was unlike anything in their experience particularly noteworthy.
The object traversed a significant arc of sky in a short time, maintaining a straight-line course without the gradual turns characteristic of conventional aircraft. No sonic boom was reported despite the apparent supersonic speed. The observation lasted long enough for multiple witnesses to confirm each other's descriptions.
Blue Book investigators checked all military flight operations in the San Antonio area for the date and time in question and found no correlation. The object's reported speed, lack of sound, and disc-like profile did not match any known aircraft type. Weather balloon launches from the area were accounted for. The case was classified "Unknown," adding to the growing number of unexplained military-area sightings in 1952.