PF anon here. Cannot help but notice that, since reading the news story a couple days ago in which Russia threatens to wipe out the entire US with just four Satan II missiles in chilling warning over Ukraine, the US appears to have switched off ADS-B tracking of various aircraft that would be potentially involved in a nuclear conflict. Namely E-4s, E-6s, and B-52s. Have not seen any at all. And this is unusual to persist over a period of two days. Especially the E-6s. Previously, under normal circumstances, an E-6 would be up and visible at all times. Or if not at all times, then a very large majority of the time. PF says they went dark due to concerns over what has been said in the press.

https://www.the-sun.com/news/5460070/russia-threatens-to-hit-us-with-satan-missiles-ukraine/