I worked height finder maintance in the USAF from 1967-1970.While I was stationed at 778 radar site in Havre Mt. In the evening after finishing shift checks and routine maintsnce on the height finder scopes, I was talking with airman Natzel who was the heigth scope operator when Natzel said look at this! He had a heigth request for a object at 85000ft. I moved to a search scope the object was moving from west to east north of the site. the search radar sweep moves at five RPM from the time I started watching the object it painted on three sweeps and had traveled approx.250 miles. The radar only covers 300 a 300 mile diaimanter. Havre AFS is located 40 miles north of the town of Havre Mt.and 4 miles south of the US and Canada border. The object was over Canada. To this I do not know what I saw on radar that night .