I wonder if that's a response to the recent (three weeks ago, Flight 2292, Cincinnati to Phoenix) American pilot's observation that something 'cylindrical' flew right over the top of his aircraft, 'that almost looked like a cruise missile type of thing'.

https://nypost.com/2021/02/23/american-airlines-pilot-report...

Sounds like dumping alien bodies into the sea :-)

I wonder if notams like this are diversions for activities else where. Pretty fun to imagine what our tax dollars are being spent on!

>The notice outlined a path 20 nautical miles wide and 426 miles long at an altitude between Flight Level 450 and Flight Level 600, or 45,000 to 60,000 feet.

What usually flies between 45 and 60k feet? Anything cool?

Commercial airliners are usually below this altitude, it’s the upper end from private jets. A G6 has a max altitude of 51,000ft. They routinely cruise around 49,000ft.

Above FL60 is uncontrolled airspace. That means the NOTAM covers UP TO 60k. They can easily traverse higher without issue as they are not required to file a NOTAM for above that altitude. I think a lot of people are missing this point.