1897 April 21 — 8:00 p.m. A man is riding his horse between Lancaster and Baltimore, Ohio, when something scares his horse. He sees an object with two brilliant white lights on either end landing in a nearby field. He tethers his horse and approaches the object, which seems as large as a house. Inside he can see two men conversing, so he walks up to ask them questions. One of the aeronauts seems to be Japanese and the other speaks English with a British accent. The craft is called the Aeribarque, and they are on a test flight. The aeronaut says that they often land in remote areas and come to nearby towns for supplies or mechanical parts, posing either as tourists or “harmless cranks trying to invent perpetual motion.” After giving the witness a demonstration of the electrical lighting system, they take off into the sky. 

1897 April 21 — 11:00 p.m. Confectioner John S. Scheer, Frank King, and Frank Mulick of Erie, Pennsylvania, watch a cigar-shaped, winged object moving north at a relatively high rate of speed. It has a large propeller on its tail end, but it flies silently and disappears over Lake Erie.

1952 April 21 — The Canadian Defence Research Board establishes a UFO study group that meets for the first time today. Project Second Storey, formed by Omond M. Solandt, DRB chairman, meets at least five times. It is chaired by astrophysicist Peter M. Millman and includes Wilbert B. Smith and representatives from Naval Intelligence, Military Operations and Planning, and the Defence Research Board. At its April 24 meeting, it decides to liase with the US government on UFO matters. http://luforu.org/ottawa-ontario-canada-north-america/

1976 April 21 — Night. RCMP Constable Bill Toffan sees an apparent vehicle with its lights flashing ahead of him as he is driving on Canada Highway 16 about 60 miles east of Prince Rupert, British Columbia. As he draws next to it, he sees it is actually in the air. Suddenly there is a blinding flash and he nearly loses control of his car. After a brief report appears in the press, the RCMP orders Toffan not to discuss the incident.

1991 April 21 — 8:00 p.m. Captain Achille Zaghetti and his copilot are flying a McDonnell Douglas MD-80 Alitalia airliner with 57 passengers. They are over the English Channel just off the coast of Romney, Kent, and preparing to land at Heathrow Airport, London, when they see a round object or missile, about 10 feet long, approaching from their left. It is less than 100 feet away. The control tower confirms a radar target, which is now behind them. The British Army denies firing any missiles. The British Civil Aviation Authority concludes that “extensive enquiries have failed to provide any indication of what the sighting may have been.” Nick Redfern notes that the description of the UFO is consistent with a pilotless drone of the type used for defense practice.

1996 April 21 —Around 9:00 p.m. Terezinha Gallo Clepf is celebrating her 67th birthday at the restaurant at the Parque Zoobotânico Mun. Dr. Mário Frota in Varginha, Brazil, when she steps onto a porch to smoke a cigarette. She looks to her left and sees a strange creature with bright red eyes and a yellow helmet on its head. It is behind a fence that circles the porch. They stare at each other. Clepf goes back into the restaurant but soon comes back out and the creature is still there. She gets her husband to take her home.