Metalic saucer hovers over us in broad daylight at around 500 feet low.

It was the summer of 1971 and I was spending vacation with my cousin on their beautiful farm in southwest Missouri. I was twelve and he was thirteen. That morning everyone went shopping except us two boys, and am I glad, for I witness something that clear sunny day that I will never forget.
As we played football in the front yard, around 11am a mid-sized metallic saucer with a round disc on top silently floated over top of us at about a 70 degree angle and within 300 to 500 feet in altitude. It was large enough to see clearly but looking straight up at it I didn’t see much except some round opaque portal like windows that you would see in the older type sci-fi renderings of UFO’s.
After a moment of amazement, I asked cousin if he would get a camera, so he hesitantly ran after one. The vessel continued to float silently above me at nearly 90 degrees for maybe a minute or so and seemed to be interested (?). I climbed upon a stump thinking to get a better look at it as I was in a state of astonishment and curiosity.
Cousin came running out of the house with some cheesy little camera that wouldn’t work but by that time it was all over with anyway. Two Air Force jets came blasting over the horizon straight for us and the UFO.
The UFO displayed an amazing ability to accelerate!  Judging by the speed of the jets (I have seen them break the speed of sound and our windows in the 1960’s) I would guestimate that this vessel would have reached a speed of over 1500 miles per hour within a 2 or 3 second burst (more like a highly controlled fling with a bit of a slow start). It looked to me like the jets were at about 600 miles per hour (pretty fast being that low).
The UFO emitted a turbine like sound as it accelerated, but not loud or harsh and as the jets roared past (they were higher and a further away, maybe half a mile) they drowned out any other noise we might have heard. One jet turned around while the other continued the chase which was clear to see that it was a joke. The UFO disappeared into the blue with the jet dogging behind him.
No sooner had the one jet turned around back over the horizon than two more jets screamed over in full sprint the same direction the first jet and the UFO had gone. A total of four jets had pathetically pursued this un-worldly craft. All I can say is our military hardware looked primitive and cumbersome compared to the ability of the UFO.
And just that quick it was all over.
Witness indicates that the date of the incident is approximate.  PD