bright red, heart shaped vehicle flying above tree tops mid-afternoon on a clear, sunny day day

This sighting was sometime mid-afternoon on a bright sunny day.  I am not sure of the exact year but it was most likely in the mid 1970's.  I grew up as an Air Force brat and my father was chief executive officer (director) for the Air Force Museum at Wright-Patterson AFB in Dayton, OH for 5 years. Therefore, I am and was familiar with nearly every aircraft our military has flown. At the time of the sighting, I lived on a 98-acre farm just north of Denton,TX, and I was a high school teacher.
The farm was located in a creek bottom area in a flood plain adjacent to Core of Engineers property. My mail box was located about 1/4 mile from the house on the blacktop road above (elev.) the creek bottom. As I got out to check my mail, the object flew directly over me and across the tree tops in a NW direction. My description of the object and event: Bright fire-engine red heart-shape like a thick, fat Valentine heart (the pointed end of the heart was the forward or leading edge); no visible windows: no noise; no vapor trail; air speed was about 50 to 60 mph; flew in a straight line only, no turns. I am guessing that it flew only about 100 to 200 feet above me and estimate it's size to be in length and width approx. about the same as an F-16 fighter jet, it was in a thick, heart-shape as I stated earlier. I knew immediately that this was not something I could explain or that it was anything I had seen before. I was excited, jumped back into my truck as I watched in cruising away, and raced to the house to ask my wife and a girlfriend of hers if they saw it or heard anything since the object had to fly almost directly over the farm house. They did not hear or see anything. I drove back to the mail box so I could see over the trees and of course it had disappeared. I don't know why I never reported this until now except that I have never seen or heard of a report of a UFO that describes something similiar or exactly what I saw. I know what I saw, it was a perfectly clear day, and it was too close to me for me to be mistaken or confused about its description.
Source of report indicates that the date of the sighting is approximate.  PD