There have been sighting for many years, including famous one over Washington D.C. in the early 1950s. Sightings during World War II (pilots called them “foo fighters”).
https://en.wikipedia.org/wiki/1952_Washington,_D.C.,_UFO_incident
https://en.wikipedia.org/wiki/Foo_fighter
https://en.wikipedia.org/wiki/List_of_reported_UFO_sightings