Yesterday, the Associated Press reported that the Cessnas some Americans have seen flying counterclockwise for hours above their cities are, indeed, FBI surveillance aircraft. FAA regulations make it plausible to track these flights in real time, if you know the tail numbers. But the FBI is apparently in the process of scrubbing a lot of their records from popular flight trackers — the aircraft mentioned in this Reddit comment apparently hasn’t flown in nearly a year. According to the same commenter, grain of salt implied, several of their aircraft are now sharing tail numbers.
It’s understandable that new surveillance methods are required as technology changes, but a federal agency flying a plane overhead equipped with technology to intercept cellular calls seems more intrusive than it could possibly be worth. Or, at least, until the FBI produces evidence otherwise, if they can.