Silver sphere flew overhead at high altitude with two delta-wing fighters in pursuit.

Time is late summer of 1968.  Afternoon.  Observer location at the Eastern end of Manor Road, Church Hill, PA (located on US 322 between Reedsville and Milroy). Visual angle on the object was about 85 deg above horizon.  Object appeared to be silver sphere, moving from North to South.  Sighting started & ended about 45 deg to either side of zenith.  Two delta-wing fighters (considering the year probably F102s) trailed yhe onject (in terms of flight path), with distance between the object anbd the fighters increasing -- ie, object appeared to be faster than fighters. Object was *not* a reflection from a conventional airplane.  The angle between the sun (cloudless day) changed markedly between beginning & ending of sighting, but the appearance of the object as a silvery sphere did not vary. Also, the fighters were always visible as conventional aircraft throught the sighting. The question, of course, is:  what was the actual altitude of the UFO? If at the fighter's altitude or greater, it was going faster than the fighters.  If less than the altitude of the fighters, it could have been slower than the fighters -- and if enough lower, could have been a balloon. At no time during the sighting did it *feel* like it was a balloon, however.