"Testing of certain aircraft?"
20 years ago this August, my sons and I were deer hunting in the Lost Cost area of N California. As we were jumping over a small creek, a plane broke the sonic barrier, probably a Black Bird.
My first thought was one of my sons accidentally fired his deer rifle. That didn't happen. My younger son ended up tripping and falling back into the little creek. He was really scared. The older son looked up as the boom was continuing as saw a black speck disappear in the WNW sky.
Later that afternoon the foreman of the ranch said that it probably was a Black Bird from Beale Air Force Base, north of Sacramento. He said that it wasn't the first time that a blackbird pilot went to full power and the sound wave came back over the coast.
Having said that, in 30 years we have heard and seen some weird stuff coming from Vandenberg Air Force Base or returning. Usually that was on the coast of N. Califonia north of San Francisco. A few days after the event, the San Francisco Chronicle would have an article buried somewhere telling that the noise and lights came from Vandenberg or were headed back.
A similar thing happened to me 40 years ago. I was hunting deer in the Northern part of lower Michigan.
A B-58 did a supersonic run very close to tree top level.
I had to return to camp for clean long johns.
By the way I didn't see either of those two blackbirds that weren't in Oki in the 60's.
Whidbey is an air force base is it not? Isn't that where our team from the surveillance plane the chinese downed originated?