Nearly 600 jobs could be created in Oklahoma, the first state chosen as a testing site for small unmanned aircraft systems, commonly called drones, in the first three years after the aircraft is allowed to use domestic airspace, state and industry officials said Wednesday.

The Federal Aviation Administration is expected to approve regulations for the drones by 2015, and it's possible Oklahoma could gain hundreds more jobs by 2025, according to a study commissioned by the Association for Unmanned Vehicle Systems International.

Companies are testing drones in restricted air space over Fort Sill near Elgin. The U.S. Homeland Security Department selected the site last year; the program is funded to run through December, said John Appleby, with the federal agency's advanced research projects division.

The robotic aircraft being tested is to be used for purposes such as search-and-rescue efforts or responding to natural disasters such as tornadoes and fires. Tests are conducted at the University Multispectral Laboratories flight center, which is affiliated with Oklahoma State University.