One extremely large, dark gray triangular shaped object with no lights or markings on it over Tucson, AZ. (1988)

While driving south on Craycroft from Broadway Blvd toward the Tucson airport, I noticed a triangular shaped object in the sky. It was so large I couldn't quite believe what I saw, but kept driving unsafely, until I was another mile south. I was at an intersection near Ajo Way when this object seemed just as large as before. I stopped in the right lane of that intersection and a woman in a vehicle to my left seemed to see the object in the sky also, and we made eye contact. We both stopped and I pulled over to the shoulder. The object was a gigantic triangular shaped form. It was very dark gray in color with no lights or printing/insignias on it. This was a very brilliant day, with no clouds, so this object was clearly visible, and it was not a "mirage" or a cloud. I stayed parked at the roadside fore at least 3 minutes watching this object hover motionless over the Tucson International Airport and the Davis/Monthan Air Force Base area. It did "hover motionless" for that time, because I became very hot and thirsty, and also stunned at this sight. I can't recall anyone else stopping to view it, except that one woman I made eye contact with. She was gone. The large gray object "dipped" its wing, so I could see a dimension of how large it really was. It was like a city block long. Very suddenly, it disappearred. I was thinking I had a dream or a day-dream, but I know certainly I didn't. I was very sobor and I don't do any drugs, so I was very afraid to tell anyone about this. I told one person, but he said that I saw a new US "secret bomber". Nope. This object had a very definite triangular shape, made no sound, stood still in the sky for too long and would certainly have made great news, if reported to the authorities.
Date is approximate.  PD