I just read the siting report that you attributed to 1973.

A friend of mine told me a story about how he and a group of very smart but michievous friends spent months designing and creating two "UFO's," purposely designed to show up on radar, which they launched from different locations, then contacted a radio station to report to get people out to see them. Fighter jets were scrambled. Authorities never figured out what the "ufo's" were.
I remember bits and pieces of the whole story but could try to explain to someone if you wanted to know.  However, the details I was given seem to fit with what the other person reported here.
NUFORC has assigned an arbitrary date; source of this report does not indicate which report she alludes to.  We are aware of many such stories, many of which go back to the 1950's and '60's.  One notable such incident occurred at Princeton University in New Jersey.  PD