I wouldn't worry too much.
I just happen to live within a mile of a major airport.
Not only that, but my house is located directly under their "approach" path for landing on the runway.. so I've got air-traffic flying over my house daily on a constant basis. Not only do I have civilian aircraft flying over my house all the time.. but the airport actually has a military base that sits on the same land as the airport. So, not only do I get to hear the commercial/civilian airplanes all day and night... but I also get to hear those loud ass fucking military jets/planes. And oh man, they're so fucking loud that I can't even hear myself think when they're taking off or flying over my house coming in for a landing. Sometimes, its so loud.. it literally shakes my house and the walls. The military base switched over from using their training jets (F-16 jets).. over to using the new A-10 WartHogs (warhog or warthog..one of those) and let me tell ya, those bitches are twice as fucking loud as the old F16 jets they were using before the switched.
I also get, occasionally... I'll get some military helicopters that fly training missions.
Now, not only do I have all that air-traffic from the airport and the military base.. but then, I also happen to live no further than a half a mile away from a major hospital. Which isn't that big of a deal, I actually like living close to a hospital because ya never know when you might need an ambulance or need to be rushed to the emergency room. However, they've got an 'Air Angel' helicopter that they use to transport people to and from the hospital.. which, believe it or not.. I'm also located directly under their "flight path" as well.
So, combined.. I have civilian/commercial air-craft; then I have military air-traffic; and then I even have the hospital helicopter air-traffic.. all of which fly directly over my house on a daily basis. But, I don't worry about any of it... and neither should you.
The only time you should worry about helicopters.. is when they begin to circle your house. If they begin to circle your location.. that's usually a good indicator that they're looking at you and or investigating you.. or! they just happen to get a nice heat signature off your house and it got their attention. So, again.. as long as you don't have a helicopter hovering above or circling your house/location.. then you'll be just fine.
peace.