Something Going On?

Last night I heard a helicopter flying overhead, and realized it's a sound I have never heard here in my neighborhood. I wondered what it was; it's unlikely to be surveying, say, traffic, since I live nowhere near a highway, and it was late at night, long past rush hour.

Then, just now, I twice heard military planes flying over my head. The second time I rushed to the window and saw four planes in formation swinging upward together. It was pretty, but again, a little weird seeing it here. I live nowhere near an air base and can't remember this happening before, where I live.

Is this some sort of pre-Memorial Day practice for the military, or is something (even more unusual than "normal" here) going on? It's giving me the creeps.

I'll assume for now it's pre-Memorial Day practice, for tomorrow's commemorations of fallen soldiers. That's the story I'm sticking to, until I hear otherwise!

PS. I just spoke with someone more "in the know" about these things (whom I'll name if he tells me it's OK; I didn't ask), who said that the planes today are mostly likely a rehearsal for tomorrow, and the helicopter last night was probably a signifier of the increased security in the country right now, due to the attractive nature, to our enemies, of attacking us on Memorial Day or Independence Day.