After retrieving the body of the dead alien, the saucer lifts-off, returning the fire, spreading destruction across the facility, and killing everyone but the Marvins, who were trapped below ground.

Major Huglin and the Marvins are released with the message that the aliens want to meet with the world's leaders in 56 days in Washington, D.C. to negotiate an occupation of Earth.

Dr. Marvin's later observations lead to the discovery that the aliens' protective suits are made of solidified electricity and grant them enhanced auditory perception.

For increased realism in the scenes depicting saucers crashing into monuments and government buildings, he also animated falling masonry.

[8] A scene depicting planes crashing after being hit by an alien ray utilizes film of a 1944 accident at an airshow near Spokane, Washington involving military aircraft.

[9] The film's iconic flying saucer design—a stationary central cabin encircled by a rotating outer ring with slotted vanes in it—matches purported eyewitness descriptions recorded by Maj. Donald Keyhoe in his best-selling non-fiction book about UFOs.

At a tribute to Harryhausen held in Sydney, Australia, the animator said that he consulted with well-known 1950s UFO "contactee" George Adamski about the depiction of the flying saucers in the film.

[11] A reviewer for Variety commented that the special effects were the real stars of Earth vs. the Flying Saucers: "This exploitation program does a satisfactory job of entertaining in the science-fiction class.

The technical effects created by Ray Harryhausen come off excellently in the Charles H. Schneer production, adding the required out-of-this-world visual touch to the screenplay, taken from a screen story by Curt Siodmak, suggested by Major Donald E. Keyhoe's Flying Saucers from Outer Space.

"[12][13] The Los Angeles Times was also fairly positive, writing that although the saucers "look like art department concoctions", the film still "has a sort of pseudoscientific charm".

[1] The Monthly Film Bulletin gave a negative review, stating that the "semi-documentary technique" was "pretentious" and the use of stock footage, "crude model-work", and most of the best-known science-fiction clichés made the movie "a long-winded and rather bleak invasion from outer space".