The annual Legacy Air Show in Rexburg attracts stunt pilots and vintage aircraft from around the country.
Air show official Brad DeBow told the Rexburg Standard Journal (http://is.gd/KqDX7u) that pilot Buck Roetman of Sharpsburg, Ga., appeared to have a broken ankle.
After the plane lost power, DeBow says Roetman aimed for a clear spot on the edge of the course, just east of the airport.
Witnesses say the pilot was doing a series of rolls when the plane went down near a group of trees.
The cause is under investigation.
The accident follows a September crash at an air race in Reno, Nev., that killed 11 people and injured about 70.
Information from: Standard Journal, http://www.rexburgstandardjournal.com/