Fran, the primary reference is the Louisville [KY] Times article of 7/6/1950. This article was sent around the nation maybe by the UP, and the Pentagon saw it. General Cabell got interested and asked Grudge to obtain the film. Grudge, in the person of Bruno Feiling, wrote back saying that they didn't want to do this because they'd have to identify themselves and this would create the [then currently viewed as] bad resultant of noticing the public that the USAF was still involved. A discussion went on in the Pentagon/WR-PAT airwaves as what to do about this sort of thing in the future.

Loren Gross notes this, and cites Hynek's UFO Report.

As to the film, I've not seen it. Someone claimed that there was a picture in a REAL UFO Special of 1966, but I don't have that and don't know if it's true. Al Hixenbaugh also claimed a still shoot of UFOs in 1947 [which is around] and could cause confusion.

I think it was Dr. George Valley, MIT & UFO monitor on the AF Scientific Advisory Board who wanted the film.  Essentially everyone, AF Intel, AFOSI, local AF people did not want to get involved.  Gross disrespect to Valley.  I saw this in the PBB files prior reading it in Hynek. Seems like the AF didn't want to seem to be publicly interested in UFOS at all.