
In Tonpa AFB US air force held a whole squadron of various Migs. Squadron was used to practice dogfights etc. They knew when Soviet satellites were coming and would move all the Migs into hangars.If I remember the story right the Godless Commie Russkies knew about Area 51 from the very beginning and had it under observation. The people working there knew that an had a schedule of when various satellites would pass overhead so they could conceal whatever they were working on including this.
I think it was during Have Blue the development of the F-117 that they figured out the ground beneath the sand held the day's heat and created a perfect infrared image of the aircraft being tested