What's with planes on Memorial Day?

I realize this is not a major issue usually found in this space, but as a long time resident of the Greenbrier neighborhood in Arlington Heights, I'd like to ask your readers if anyone has any information regarding a very low flying single engine airplane circling for hours over Greenbrier School (and our house) this last Memorial Day morning.

This is at least the third time this has occurred in recent years on Memorial Day, a holiday when some people like to relax in their yards, and not be disturbed for hours by low flying circling airplanes droning overhead.

The first year this happened we contacted police, and were told it was a "traffic study".  On a holiday, flying the same small circle over a residential neighborhood for hours, polluting the air with fumes and noise? Also, no markings on the wings, which I thought was an FAA requirement?

Can anyone explain this recurring holiday intrusion?

Thank you.

Klaus Schuetze

Arlington Heights