Several circling flight patterns could be low level flight training. My buddy flew C-130 for several years and they often "Terrain Follow" to keep a low radar profile.

You'll see that often with the Blackhawks and C-130's for close air support missions. The F-15 fighter jets out of Otis use the White Mts of New Hampshire.

If there is a small runway near you, they may also be practicing their approaches.

I made a shortcut on my phone to this site. They have an app version also: ADS-B Exchange

I was having casual conversation with a current member of the army serving as a MP. He had recently returned from a deployment in Poland. I asked him what he was doing for training stateside it was worrisome since most of his training now is centered towards urban crowd, control. Your comment on posse comitatus is noted in this context.

Three Chinooks landed together at the Norwood, Massachusetts Airport on Sunday around noon. I wonder if it was the same group? Norwood Airport is one of those sleepy little town airports. It is 20 minutes from Boston, south.

I'm was told Bidan is coming, so I assumed it was some sort of advance.

Someone posted on my towns FB page this morning that 3 helicopters flew over their house this morning, someone else said they were Chinooks. This is in Western CT. Likely the same 3.

I see those guys all the time off my farm in NC, but next to my house in GA I never see them and I live next to moodys lol.