The buzz created by unmanned aerial vehicles (UAVs) at farm shows this winter was unmistakable, according to Brent Johnson, owner of Labre Crop Consulting in Manson.

"People have been reading about them for a couple of years, but having it for people to see and touch has been huge," said Johnson.

This spring, more and more tiny UAVs are buzzing above Midwestern farm fields, capturing images from high in the sky despite some cloudiness about their legality in commercial operations and how exactly farmers can best use them to increase profits.

"One of the first questions people ask is what can it do," said Johnson, who has provided UAV demonstrations for farmers, engineers, educators and the media over the past several months. "It’s actually a very difficult question to answer, depending on the model they’re looking at."

The UAVs, which are also sometimes called unmanned aerial systems (UAS), vary widely in cost and design, including helicopter-like models with four to eight rotors as well as fixed-wing models. The rotary copters are more inexpensive and maneuverable, while fixed wing aircraft are...