The earliest analyses of the Utah Film (then Top Secret) were conducted by the United States Air Force and the U. S. Navy. After the films were declassified they were used in a UFO documentary in 1956 by Greene-Rouse. The analyses showed that there was the total absence of any evidence to indicate birds, such as fluttering. Here is what the documentation showed.
NICAP Site Coordinator
This film could not be duplicated under simulated conditions.
The objects appear to be a light source rather than reflected light.
All the objects appear to be the same size and circular in shape.
At a distance of five miles, with the movement perpendicular to the line of sight, the average velocity is 653.5 mph. Likewise, at 2.5 miles the average speed is 326.75 mph.
The movement in flight appears to follow an elliptical or circular pattern, within the group.
While the objects are unidentified,
the following possibilities have been eliminated:
Within a five mile radius, aircraft
could have easily been determined. In excess of five
miles the objects were moving faster than aircraft could
achieve, except in straightline speed runs.
The image structure & maneuvers eliminates any type of aircraft.
Microscopic examinations show that the objects are in focus and 1/6th to 1/10 the size of the full moon with the naked eye.
Photogrammetric experiments have shown that the images cannot be associated with any type of bird observation at any distance.
Source: Air Force report to Green-Rouse Productions used in motion picture documentary, 1956, "U.F.O."
Dr. Robert L. Baker, Jr., was a consultant to the Douglas Aircraft Company, former head of Lockheed's Astrodynamics Research Center, project officer on a number of classified Air Force projects, and (at the time) a senior scientist with the Computer Sciences Corporation.
Dr. Robert L. Baker:
Both films had been taken by apparently reliable and unbiased men using amateur movie cameras and, in each case, there was a credible, substantiating witness present. The films exhibited the motion of rather fuzzy white dots, but the Montana film was remarkable in that foreground was visible on most of the frames.
Preliminary analysis excluded most natural phenomena. More detailed study indicated that the only remaining natural phenomenon candidate for the Utah film was birds in flight, and for the Montana film it was airplane fuselage reflections of the sun. After about 18 months of rather detailed, albeit not continuous, study using various film-measuring equipment at Douglas and at UCLA, as well as analysis of a photogrammetric experiment, it appeared that neither of these hypothesized natural phenomena explanations had merit, and a report was published by me (Baker  )and forwarded to Brig. Gen. Harold E. Watson, commander, ATIC. Since the description of the circumstances of the filming and the analyses of the data provided on the films is rather lengthy, and have since been published in the open literature, it does not seem unreasonable to repeat the analyses here.
To this date my analyses of anomalistic motion picture data have been rather ungratifying. Although I am convinced that many of the films indeed demonstrated the presence of anomalistic phenomena, they all have the characteristic of rather ill-defined blobs of light, and one can actually gain little insight into the real character of the phenomena. For example, linear distance, speed, and acceleration cannot be determined precisely, nor can size and mass. As I will discuss in a moment, this situation is not particularly surprising, since, without a special-purpose sensor system expressly designed to obtain information pertinent to anomalistic observational phenomena, or a general-purpose sensor system operated so as not to disregard such data, the chance for obtaining high-quality hard data is quite small.
Source: Hearings before the Committee on Science & Astronautics, July 29, 1968, page 127