1897 May 4 — 9:00 p.m. Louis Dumhoff, a physician living at 112 Garfield Place in Cincinnati, Ohio, sees a red, egg-shaped light, “the rays escaping in the center and at each end.” It passes to the southeast in about 5 minutes, moving in a zigzag, up-and-down course. Conductor J. C. Gaupel and attorney W. J. Klein also see the light in the same neighbourhood.

1949 May 4 — The US Fourth Army creates an operational plan for a green fireball observation and tracking network at Killeen Base in Camp Hood, Texas. Although it lacks cameras, it has four six-man observation posts equipped with instruments to obtain directional bearings. One of the posts serves as the plotting center to coordinate and triangulate UFO sightings. Each day, a roving patrol gets new orders. (Clark III 543; https://sohp.us/Sign-Historical-Group-Workshop-Proceedings.pdf 

1955 May 4 — A survey team arrives at Groom Lake, Nevada, and lays out a 5,000-foot north to south runway on the southwest corner of the lakebed and designates a site for a base support facility. The “Ranch” initially consists of little more than a few shelters, workshops, and trailer homes in which to house its small team. In a little over three months, the base consists of a single paved runway, three hangars, a control tower, and rudimentary accommodations for test personnel. The few amenities include a movie theater and volleyball court. There is also a mess hall, several wells, and fuel storage tanks. https://en.wikipedia.org/wiki/Area_51; http://area51specialprojects.com/area51_timeline.html

1955 May 4 — Afternoon. Lt. Col. Edward J. Stealy, commander of the 57th Fighter Interceptor Squadron at Keflavík Airfield, Iceland, and 1stLt. Joseph Burt see 10–15 flying objects, 60–70 feet in diameter, at about 25,000 feet. They fly in loose formation for about 4–5 seconds and are traveling at a tremendous rate of speed (perhaps 1,150 mph). https://sohp.us/collections/ufos-a-history/pdf/GROSS-1955-Jan-June.pdf 

1956 May 4 — 9:30 p.m. Rev. Charles Burmeister, an amateur astronomer, sees five “orange blobs” flying in a U-shape formation east to west at high speed over Marinette, Wisconsin. His son joins him to watch. One more object passes in the same flight path, then a group of six, then one more, followed by another. Blue Book classes the sighting as meteors without even consulting Hynek, who later says that meteors do not fly in formation. https://sohp.us/collections/ufos-a-history/pdf/GROSS-1956-May-July.pdf 

1958 May 4 — Dewey Fournet confirms, in a statement to NICAP, the existence of the Estimate of the Situation and his own motion study from 1952.

1969 May 4–9 — 3:00 p.m. A 24-year-old Brazilian soldier named José Antônio da Silva is fishing by himself at Bebedouro, apparently a small lagoon in the Área de Proteção Ambiental do Carste de Lagoa Santa near Matozinhos, MinasGerais, Brazil, when he begins dozing off. He perceives figures moving around him, and he feels himself shot with something that paralyzes his legs. Two small humanoid beings, joined by a third, drag him off into a strange machine shaped like two saucers joined together by a thick, vertical cylinder. The machine lifts off, and after a long interval it lands. Da Silva is carried by his armpits into a large quadrangular room, where he finds himself with his original three captors and a fourth being—also humanoid, with red hair and a beard that comes down to his waist—who seems to be their leader. He remembers afterward that all four have mouths that look like fishes’ mouths. The room is made of stone. Inside, on a low shelf seemingly fashioned out of stone, da Silva sees the bodies of four human men lying stretched out side by side. Naked, rigid, and positioned on their backs, the bodies bear no visible wounds, but it is obvious that they are dead. One is a well-built black man and another has light brown skin. Two others, more slightly built, are Caucasian, one of them very blond “like a foreigner.” The beings do not speak any Portuguese but, using pictures, the leader manages to convey to da Silva that they want him to be their guide and weapons provider for what he supposes is a subsequent invasion of Earth. He refuses, fingering his crucifix, which the angry leader rips from his hand. Out of nowhere, da Silva sees appear in front of him a human figure who stands motionless, gazing at him in a friendly fashion. The figure, about five and a half feet tall, is Caucasian, slender, bearded with long fair hair, and dressed in a friar’s cassock. Amazingly, the little men seem oblivious to his presence. Speaking in Portuguese, the figure gives da Silva certain “revelations” that he afterward insists on keeping secret. He apparently knows who the figure is but he does not reveal that either, saying only that he wasn’t Jesus. The figure vanishes, and the beings who have abducted him start quarrelling among themselves. They carry da Silva back to their machine; there follows another flight, another landing. Da Silva awakens in the dawn of what turns out to be May 9, four and a half days after his abduction, some 300 miles to the east of the place where he had been abducted. He supposedly bears the physical marks of his ordeal—wounds on his neck, lameness in one leg—for days afterward.  https://www.davidhalperin.net/jerome-clark-and-loren-coleman-descent-into-hell-and-the-bebedouro-abduction/ ; http://www.ignaciodarnaude.com/ufologia/FSR%201973%20V%2019%20N%206.pdf , pp. 6–14; http://www.ignaciodarnaude.com/ufologia/FSR%201975%20V%2021%20N%203-4.pdf, pp. 32–38; https://www.historydisclosure.com/brazil-1969-the-abduction-case-of-jose-antonio-da-silva/ ; https://www.fenomenum.com.br/ufo/casuistica/1960/bebedouro ; http://files.afu.se/Downloads/Magazines/Brazil/SBEDV/SBEDV%20-%20No%20094-98%20-%201973-1974.pdf

1981 May 4 — 2 :00 p.m. As he is pulling up to his home in Danville, Pennsylvania, on a motorcycle, William F. Hummer notices “cobwebs” hanging over houses, telephone wires, and parked cars. Wispy material is falling from the sky. He sees something moving around in the sky and goes in to get binoculars. He and another man watch several flying discs as they dart overhead in groups of twos and threes. One pauses and he can see it is round and metallic with a dome and “kind of peak on it.” His sister joins them and says they can see big masses of material floating around for 30 minutes.

1983 May 4 — 3:50 a.m. Police officer James Philips sees a silent, yellowish-orange ball of light over the outskirts of Lawrence, Kansas, hovering 350 feet over a power line pole. It flies away toward the northeast slowly at 30–40 mph. The sighting lasts three minutes.

1988 May 4 — MUFON Director of Investigations Dan Wright poses a set of open questions for John Lear, nearly all of which concern Lear’s sources. Lear claims that most of his information comes from confidential sources within the intelligence community, while a lesser portion comes from open sources and his own “informed speculation.” http://www.ufonet.it/archivio/john.lear.htm

1988 May 4 — During a question-and-answer session following a speech to the National Strategy Forum in Chicago’s Palmer House Hotel, President Reagan is asked about the most important “need” in international relations. He replies: “I’ve often wondered, what if all of us in the world discovered that we were threatened by an outer– a power from outer space, from another planet. Wouldn’t we all of a sudden find that we didn’t have any differences between us at all, we were all human beings, citizens of the world, and wouldn’t we come together to fight that particular threat?” http://www.presidentialufo.com/old_site/reagan_ufo_story.htm 

1990 May 4 — 11:15 p.m. A retired archaeologist in Stockay, Liège, Belgium, is about to return home after checking his greenhouse when he hears neighbourhood dogs barking. He sees, in a field about 325 feet away from him, a pyramidal or conical illuminated object topped by a “bright white mushroom cone” floating about 1 foot off the ground. He approaches to about 165 feet and watches the object change color from white to orange as its upper part rises. He calls his wife to watch the UFO too. She sees two small antennas on top. They leave to get their son, but when they return the object is gone. The next day, he finds four circular holes about 3 feet in diameter with a thin layer of yellowish powder sprayed on the grass. Some days later, the traces vanish after a rainstorm.