F4 Fighter-Intercepters scrambled to intercept object at over 90,000 foot altitude

I was stationed at the Douglas FAA Flight Service Station in 1975.  
During a graveyard shift, I went outside to do my hourly weather observation, taking the temperature/dewpoint samples.  
I noticed an object moving slowly from over the mountains to the northeast (Dragoon mountains), on a southwesterly heading towards the Bisbee/Ft Huachuca area.  I could not estimate the size or altitude of the object, but it was a light blue color and globular.  It seemed to glow and the intensity would fluctuate as it moved along.  
Having been in the USAF and around aircraft for many years, I saw that this was definitely not a conventional aircraft, neither fixed wing nor rotor.  
When it reached a point over the Mule mountains to the southwest, over the Bisbee/Ft Huachuca area, it stopped and just hung there. A couple of minutes later it started to move sporadically back and forth over that point.  
I went back inside the station and rang Davis-Monthan AFB in Tucson on our interphone line requesting them to verify a target at that location.  Davis-Monthan confirmed a target over Ft Huachuca, and their height-finder radar indicated an altitude "above 90,000 feet".  The size of the object as it appeared, and at that altitude, must have been huge.  Davis-Monthan scrambled 2 F4's.  
I went back outside and in minutes could see, approaching from the northwest, two aircraft moving towards the object and the glowing trails of their afterburners going full bore told me it was the F4s.  
When the aircraft were approximately 10 or 20 miles from the object, it suddenly zoomed away at high speed towards the southwest and disappeared over the mountain horizon, leaving the F4s orbiting around the area.  
I could only imagine what the pilots were saying to each other.  They then headed northwest towards Tucson.  Davis-Monthan had checked with the base at White Sands Proving Grounds to verify if a weather baloon had been launched recently.  They had not.  
When Davis-Monthan called back for more information, I told them jokingly..."congratulations, you just confirmed a UFO".  They were not amused.  
I did not have any other inquiries from either the Air Force people nor our FAA.  A couple of days later I learned of the new UFO Reporting Center in Seattle.  I called them and told them the story and never heard from them again.
Witness indicates that date of incident is approximate.  Witness heard back from NUFORC, on this occasion.  PD