This clip depicting the sounds generated by the 'interplanetary conveyances' in this movie is most extraordinary for their similarities to those observed in some actual cases. This may be due to the filmmakers choice in using the motors and equipment at the local sewage treatment plant for their sound effects and the fact that some UFOs use a similar sort of rotational and power generation technology in their propulsion systems.
Prior incidents in which similar sounds were detected include:
A couple of Airship incidents from Texas on April 22, 1897, Flying Saucer Review Vol 13 #1 p. 23
as well as Reedsburg, Missouri a couple years later in 1900 Midwest UFOs and Beyond p. 66
March 1944 near Kaphi Lui, Burma. Quest UFO Magazine Vol. 6 #6 p. 9.
September 1946 12 miles outside of Oklahoma City Oklahoma. Amazing Stories Vol 21 #2 pp. 175-176 (very vivid description)
November 1950 North of Merritt Island, Florida Earth an Alien Enterprise pp. 226-227
September 25th, 1952 over Camp Drum, New York. Fantastic Universe Vol 8 #6 p. 84.
January 29th, 1953, about 7 miles North of Conway, South Carolina. Male Magazine September 1953 (also Search Magazine #31 p. 30)
July 16th, 1953 over Chicago Illinois. Fate Magazine #45 p.103.
January, 1955 over Wilmington California, UFOs: The American Scene p. 53
October 18, 1955 over Williston, North Dakota, Flying Saucer Review (Gribble) Vol 2 #1 pp. 10-13
Late May, 1957 near Milford, Pennsylvania, Flying Saucer Review Vol 15 #5 pp. 14-15
Nov 7, 1957; Dugger, Indiana, The Challenge of Unidentified Flying Objects p. 108 (Citing The Hammond (Indiana) Times of Nov 10th and 13th.) and November 13th near Merom, Indiana, Fate Magazine #96 p. 33
Sept. 21 1958;
The so-called 'Fitzgerald case of Sheffield Lake, Ohio, The Challenge of Unidentified Flying Objects p. 108 (Citing The Cleveland Plain Dealer of Sept 22, 1958)
Feb. 3rd, 1959, Oil City Pennsylvania, The Challenge of Unidentified Flying Objects p. 108 (Citing The Oil City Derrick, February 4th 1959)
February 24, 1959 over Victorville, California, The Hynek UFO Report pp. 167-169
August 11, 1960, near Boulder Colorado, A Decade of Flying Saucers 1950 - 1960 p. 30(Citing Saucer News December 1960)
April 24, 1964, Newark Valley, New York, Flying Saucer Review Special Issue No. 3 p. 23
November 25th, 1964, New Berlin, Connecticut, The APRO Bulletin April 1975 pp. 3-4
September 4th, 1965, Green River Gorge, Washington, NICAP Reporter #47 p. 7
The Ohio to Pennsylvania police chase of 1966, various sources including Flying Saucers The Startling Evidence of an Invasion from Outer Space p. 250
Mid 1960s, Botany Bay, Queensland Australia, Flying Saucers Where Do They Come From? p. 53
September 28, 1966, Dallas TX UFOIC News Letter #17 p. 1
April 4, 1967, Near Melville New York, UFO Reports Involving Vehicular Interference p. 34
August 12, 1967 over Ogama, WI, Alien Invasion or Human Fantasy? The 1966-67 UFO Wave p. 102
November 15th, 1967 over Yerecoin, Western Australia UFOIC News Letter #17 p. 3, UFO Research Australia Newsletter Vol 2 #1 p. 10
July 30, 1968, over Claremont NH, UFOs: A New Look p. 21
April 16, 1969 over Middletown, OH, Eyewitness Vol 2 #1 p. 3
April `27, 1969, Portage la Prarie, Manitoba, Canada, Saucers, Space & Science #56 pp. 9-10, Flying Saucer Bulletin (SinDec) #2-3 p. 9
June 18, 1969, Noctorum Lane, Birkenhead, England, Flying Saucer Review Vol 15 #5 p. 35 NUFORO Bulletin #1 p. 4
October 30, 1969, over Waipukurau New Zealand, The NZ Files pp. 41-42
January 1st, 1970 over Dayton OH, Vol 2 #1 p. 1
November 29, 1970 Over Nauvoo, IL, Skylook #40 p. 13
30 miles from Chirundu, Zambia on July 6th, 1971, Gemini Vol 1 #2 pp. 26-27
May 25th, 1971 over Lynchford (near Hobart) Tasmania, The APRO Bulletin May-June 1971 p. 7
1972, Near Murray Bridge, Australia, UFO Reports Involving Vehicular Interference p. 52
February 21st, 1973 above Mill Springs Missouri ([ Ссылка ])
and October 18, 1973 near the Yuma Proving Grounds, AZ, Skylook #73 p. 10
Dover Tasmania on March 28th, 1973, The APRO Bulletin May-June 1973 p. 7
and Aickens, New Zealand on December 25th, 1973, Xenolog #91 pp. 8-9
sometime in Autumn, 1975 Over the Firnekas Ranch in Wyoming, Skylook #102 p. 16
and over Paradise, South Australia on December 16th 1975, Australian U.F.O. Bulletin May 1976 p. 7
near Mountain Creak, Tasmania on July 6th, 1980, UFO Research Australia Newsletter Newsletter Vol 2 #2 p. 16
as well as over Wychodz, Plock, Voivodship, Poland Aug 8, 1982, ACUFOS Bulletin #48 p. 9
over Enfield Connecticut on Oct 20, 1982, The APRO Bulletin Vol 31 #5 p. 7
over Lesslie, South Carolina on July 30, 1984, The APRO Bulletin Vol 32 #10 p. 8
Not to mention the Travis Walton case of Nov 5, 1975,
The initial sound is also similar to the 'tape rewinding sound produced by a UFO spotted over Santa Cruz CA on July 16th, 1974, The Last Great Flap 1973 - 1974 p. 18
