Despite the fact that two senior airline flight crews and a military pilot believed that they had nearly collided with the squadron of UFOs near St. Louis, the Smithsonian scientists determined that the fireball trajectory was approximately 125 miles north of St. Louis. This St. Louis UFO case shows that even experienced pilots who briefly see something which is unfamiliar can have flawed recollections of what they observed. Swann reported six of his own fireball sightings between 1964 and 1971 which had been observed in the June 26-30 period, around or shortly after midnight. Because Arnold subsequently embellished his story slightly in his 1952 book The Coming of the Saucers, it is important to rely on his original account, as reported to the Air Force. Arnold originally emphasized that the length of the objects was about 20 times their width, which would match the long luminous tail of a meteor-fireball.
Witnesses are notoriously unreliable in estimating the time-duration of unexpected events.
Witness estimates of the duration of their observation ranged from less than 15 seconds to more than five minutes. However, a stream of several fireballs would be visible for a longer time. The article by C.A. Chant included a number of sketches of the stream of fireballs drawn by observers.