1949 April 30 — Hynek turns in his astronomical analysis of Sign’s 237 cases. His contract with Sign is over.

1952 April 30 — Project Blue Book issues its Status Report #6. https://www.slideshare.net/alexpituba/projects-grudge-and-bluebook-reports-1-12-nicap

1960 April 30 — George Adamski appears on Long John Nebel’s late-night TV show on WOR. https://www.the-adamski-case.nl/his-life/final-years/ ; https://www.youtube.com/watch?v=_jclUlNXAhA

1962 April 30 — Just before 10:00 a.m. During a free-flight test (Flight 52) of the X-15 to a height of 246,700 feet (46.7 miles) by NASA pilot Joseph A. Walker from Edwards AFB, California, to Ely, Nevada, the instruments photograph 5–6 cylindrical objects. No visual confirmation. On May 11, at NASA’s Second National Conference on the Peaceful Uses of Space in Seattle, Walker mentions the objects photographed (and perhaps shows the slides; it is not mentioned in the proceedings). NICAP is unable to obtain the photos. NASA claims the objects are ice flaking off the aircraft (“fireflies”). They are described by a NASA spokesman as “barbell shaped, bright-orange in color, and passing in groups up to six behind the X-15.” Opinion ranges from “definitely something up there,” to “film spots,” to “sun rays on the lens.” http://magoniamagazine.blogspot.com/2014/01/fireflies.html  Jacobsen implies it was the A-12 test the same day. 

1963 April 30 — Adamski arrives in Copenhagen for another scheduled lecture tour of Europe at the invitation of Hans C. Petersen, He attends the Skandinavisk UFO Information Congress in Frederica, Denmark. (https://www.the-adamski-case.nl/his-life/final-years/)

1964 April 30 — A B-57 pilot at Holloman AFB, Alamogordo, New Mexico, radios to the control tower that he is watching an egg-shaped, white UFO with markings that match the Socorro object. He continues to watch it as it lands at the base. Coral and Jim Lorenzen insist they heard the story from a reliable source. In addition, a ham radio operator claims to have heard the exchange between the pilot and control tower. Holloman AFB denies the incident occurred. Shortly afterward, an airman walks into a clothing store in Alamogordo and spins an incredible story of a UFO parked in a hangar under heavy guard at Holloman. A couple days later, he returns to the store and denies everything. http://www.nicap.org/reports/640515whitesands_report2.htm

1976 April 30–May 1 — The Committee for Scientific Investigation of Claims of the Paranormal is launched at a specially convened conference of the American Humanist Association. Paul Kurtz, James Randi, Martin Gardner, and Ray Hyman take seats on the executive board. The committee will be funded with donations and sales of their magazine, Skeptical Inquirer. https://en.wikipedia.org/wiki/Committee_for_Skeptical_Inquiry 

1976 April 30–May 2 — The Center for UFO Studies holds its first conference on UFO research at the Lincolnwood (Ill.) Hyatt House. The proceedings are published later in the year, featuring papers on sighting waves, exosociology, and humanoid reports. Presenters include Ted Bloecher, Ann Druffel, Loren Gross, Richard H. Hall, David M. Jacobs, James McCampbell, David Saunders, Leo Sprinkle, David Webb, and Ray Stanford.