Can you face the entrance a different direction? Sounds like when they are mowing in their own yard, they are going right through the flight path. So, the hives must be really close to the property line.
As others have said, if you have 17 acres, surely there's a place you can put them where the neighbors can't even see them? Out of sight, out of mind. Or put them on the other side of your house. At the least, put them with the entrance facing into your lot, not toward the neighbors, and a lot more than 3 feet from the property line. Even though I'm a beekeeper, I would be annoyed if I was mowing my lawn and my neighbor had arranged hives so when I was minding my business mowing, I was in his/her bees' flight path.
Or put a fence up around the hives to make the bees fly upward. I have a tiny yard, and my hives also face the neighbors. But there's a 6-foot fence about 4 feet in front of the entrance, plus buildings, trees, etc. on all the other sides of the hive, so my bees fly straight up as soon as they come out. They're like 20 or 30 feet high before they fly over the neighbors. The neighbors never even see them. The fence doesn't bother me since I don't work the hives from the front.