Incident No. 122 -- 5 April 1948, Holloman Air Force Base, New Mexico.
Three balloon observers saw an object very high in the sky, moving faster than any known aircraft and possessing a rounded indistinct form, which disappeared suddenly. It was seen less than thirty seconds and was apparently not manned, judging by its violent maneuvers. For analogous size they stated if the moon were the size of an orange the object would approximate the size of a disc.
AMC Opinion: No explanation. However, the above comparison of size is to be noted. A dime held at arms length would shield the moon from the eye even if the moon appeared several times larger than it does. To reduce the proportion then, this object must have appeared as an infinitesimal point. From trained observers, this is certainly a major discrepancy.