1897 April 28 — 8:00 p.m. Hiram C. LaGrone hears a disturbance among his horses on his ranch at Deadwood, Texas. Stepping outside, he sees a brilliant, multicolored light approaching from the southwest. It slows, hovers, then lands in a field. LaGrone walks up and discovers five men, two of whom take rubber bags and procure water from his well. The other three tell him that this is one of five airships touring the country (and the same one that landed in Beaumont on April 19).

1949 April 28 — Some printed copies of Air Intelligence Report 100-203-79, “Analysis of Flying Object Incidents in the United States,” bear this date, although it was originally released December 10, 1948. http://www.project1947.com/fig/1948air.htm

1949 April 28 — Kaplan, LaPaz, Rees, and Neef meet with security officers at Los Alamos National Laboratory to discuss green fireball observations at that facility. https://sohp.us/collections/ufos-a-history/pdf/GROSS-1949-Jan-Jun-SN.pdf 

1949 April 28 — 5:45 p.m. Howard Hann [Hamm?], a Mr. Hubert [Huber?], and Tex Keahey see a very large, bright, sausage-shaped object travel from northeast to southwest over the rim of the Catalina Mountains near Tucson, Arizona, over a period of 12 minutes. The object is shiny metallic and reflects the sun, apparently revolving as it moves like the “slow roll of an airplane.” There is no noise, nor is there exhaust or a vapor trail. There are no wings or engines or “protuberances of any sort.” It appears to be traveling at 300–600 mph. http://www.nicap.org/490428tucson_dir.htm

1949 April 28 — 8:30 p.m. Several security patrols at Killeen Base, Texas, report nine separate sightings of lights southeast of the base. Most change color from white to red to green. On one occasion, four lights appear together; on another, 8–10 show up in each other’s company. No debris or evidence of flares are found. 

1956 April 28 — At the third Giant Rock Interplanetary Spacecraft Convention, contactee Dick Miller plays tape recordings allegedly made by Mon-Ka, a Martian, in which he asks Los Angeles radio stations to shut down for two minutes at 10:30 p.m. on November 7, 1956, so that Mon-Ka can speak from his spacecraft. As a publicity gimmick, two radio stations (KATY [now KYNS] of San Luis Obispo and KBIA of Los Angeles) go off the air at that time, and KTTV in Los Angeles sends up an airplane to watch for the approaching spacecraft. Nothing happens.

1964 April 28 — Early evening. A round, whitish object hovers then darts away over Anthony, New Mexico. State policeman Raúl Arteche sees it moving west over the Port of Entry near El Paso, Texas. He says it looks like the object Lonnie Zamora saw. 

1964 April 28 — Early morning. Don Adams is driving in Edgewood, New Mexico, when his car stalls. He sees a glowing, greenish object 100 feet overhead and fires six rounds.

1967 April 28 — Condon recommends J. Allen Hynek and Richard H. Hall to Encyclopedia Britannica as excellent persons to write UFO entries. 

1967 April 28 — 11:30 a.m. Brian F. Jenkins and seven other coast guards at Brixham, Devon, UK, watch a huge, cone-shaped object through 25x binoculars mounted on a tripod. The object is hovering at 15,000 feet and seems to be revolving. Jenkins says the cone is pointing down, and the object seems made of glass or highly polished metal: “Near the bottom there was a triangular-shaped opening or door with a white rim on the top that reflected a lot of sunlight. The bottom was crinkled, very white, and seemed to consist of strips of metal hanging down.” It drifts to the northwest, rising to 22,000 feet and 8 miles away. At 12:40 p.m., a jet aircraft approaches it, flies above it, passes it, turns, and approaches it from below before it disappears from sight. Possible balloon.