[Embraer]

Within the last 10 years I was a controller at LA Center. I have since moved on to another facility. I worked U2s daily...as they descended BACK into controlled airspace, which was always fun. It was neat talking to the pilot on discrete tac frequency, especially since with his positive pressure suit, he sounded like an astronaut on the radio. When I keyed up, my transmissions would broadcast on several frequencies, tac/uhf/vhf, so every other pilot in my airspace would hear what I was saying to him....but they couldn't hear what he was saying to me. When I'd say "Upon descending back into Class A airspace, would you like to enter the complex at altitude or would you like an enroute descent?" ....about every pilot on frequency would key up and ask what kind of aircraft I was talking to. Of course, mum was the word. It was always great fun. Sometimes it was U2s. Sometimes it wasn't. They would always report their altitude to us as something in coded language ....depending on the week (it was constantly changing...we had a TS panel we had to access beside our scope which gave the key to what which altitude corresponded to what code they told us they were at. These codes were changed all of the time, so we would have to reference that to verify his altitude.

We also had a supersonic corridor that traversed my airspace, as an extension of the Edwards complex. It was routine to see experimental aircraft coming in and out of Groom Lake that were most definitely exceeding (by a large margin) Mach 3 in block altitudes of FL550-590. This was circa 2013-2014. In strange bit of black project humor....they would file their flight plan with bogus AC types listed. IE: XXX as the type. Or sometimes something goofy like an F-4 or F-5. Or a T-38. F-16's would be supersonically flying chase, and the "F5" would walk away at well more than twice the speed they were at.

If you've spent any time in Palmdale, you'd be used to hearing sonic booms in the morning. Still happens over the Mojave desert.