What Was Pulsing & Whirling Over Kalamazoo Overnight?

I’m not the kind of person to jump to conclusions, but something was happening overnight in Kalamazoo, that I originally thought was a figment of my own imagination, but was apparently affecting other people in the area.

I randomly woke up at around 1:45 in the morning and thought I was hearing some kind of pulsing noise coming from outside, but I figured it was probably an air conditioner. My suspicions were confirmed when I logged onto Facebook and I saw a friend questioning if anybody else was also hearing the noise. That’s what I knew it wasn’t the air conditioner, and the noise could apparently be heard from a ways away:

Has anyone else in Kalamazoo been hearing a weird pulsing/whirring sound for the last hour or is that just us?

One of his friends who lives in Portage even claims to have heard it also:

I think I hear what you’re talking about. Well I though I did just like two minutes ago. I’m by the airport so I thought it was an aircraft of some kind.

Aliens?

I know what you're thinking, but there's no logical explanation why a whirling noise from an aircraft we control should be heard in Vine neighborhood, Portage, and on the corner od Drake and KL Avenue.

I think there may be a bit more to this than we know, and I'm hoping that someone can address the city and in turn, we can find out what the noise originated from. Until then, keep your eye on the skies.

Drone?

A friend made a note that there's possibly a rather large drone in the area:

Apparently, there's a drone that's been flying over my neighborhood that's the size of Volkswagen. It's very loud, low flying and has red lights. It's on my neighborhood FB group all the time. Maybe that was it?